Current Research Projects
Dynamic Tire Modeling for Off-Road Vehicles: Applications to Semi-Active Vehicle Suspensions
Buckner, Gregory
01/22/2008 through 07/22/2009
Lord Corporation
The design of controllers for active and semi-active vehicle suspensions has been the focus of extensive research in recent years. Typically, researchers utilize low-order, linear, time-invariant models for controller design and simulated performance evaluation. Such models tend to be easy to develop and utilize in the design process. However, the dynamics of tires and suspension components is inherently nonlinear, particularly for off-road vehicles. Off-road vehicles experience large tire and suspension displacements, where the nonlinear kinematics and damping characteristics are significant. The accuracy of low-order, linear models is inadequate for such applications. Other researchers have developed sophisticated tire models using finite element analysis (FEA) and other techniques. While the accuracy of these models is superior, they may contain thousands of states and require extensive computational resources to perform offline simulations. The complexity of FEA models make them impractical for controller synthesis. The objective of this research is to develop and experimentally validate dynamic models of tires and suspension components for off-road vehicles. The focus will be to optimize the accuracy/complexity tradeoff, so that these models may later be used for the synthesis of control algorithms for semi-active suspensions.
Rapid Method For Computing Heating Rates on Hypersonic Vehicles Using Unstructured Grids
DeJarnette, Fred; Hamilton, Hubbard and Weilmuenster, Kenneth
12/11/2007 through 12/10/2009
National Aeronautics & Space Administration
This proposal pertains to Project A.5: Hypersonics, Topic A.5.3 Aerodynamics, Aerothermodynamics, and Plasma-dynamics, Subtopic A.5.3.3 Optimization tools and error and uncertainty estimation techniques. The overall objective of this topic area is to provide advanced flow-simulation capabilities that include all relevant physical phenomena in the hypersonic flow regime. These capabilities will enable the development of improved predictive and uncertainty qualification techniques that will in turn improve NASA's ability to design, test, operate and maintain future hypersonic vehicles, including HRRLS and HMMES. It is desirable to include most of the physical effects like flows containing multiple bodies, shocks, shear layers, with laminar, transitional and turbulent regions; radiation effects; nonequilibrium gas effects; radiation properties and gas-surface interactions. It is not likely that all of these effects can be included in a computer code needed for the time frame of designing vehicles for exploring the moon. The current proposal has as its objective to develop an approximate computer code to calculate heating rates over hypersonic vehicles very quickly and reasonably accurately for preliminary design where many solutions are needed for design optimization and also for error and uncertainty techniques. The Co-I's and PI have developed an approximate engineering computer code called LATCH (Langley Approximate Three-Dimensional Convective Heating) which is based on the axisymmetric analog, data from structured grid based inviscid flowfield solutions and an approximate boundary-layer method. This code has been shown to provide accurate predictions of laminar and turbulent convective heating in regions of attached flow for three-dimensional vehicles such as the Shuttle Orbiter as well as boundary-layer transition parameters used to estimate the onset of boundary-layer transition during the Shuttle Orbiter Return to Flight and follow on missions. The LATCH code is tied to a single block grid topology which limits the code in two ways. First, it is difficult, if not impossible, to create a single block structured grid about most complex geometric configurations. Secondly, the creation of structured grids is time consuming and is not amenable to the parametric analysis of multiple perturbations in a vehicle configuration required in a vehicle's preliminary design phase.
5th Annual NIA/NASA/Space Grant Educator Training Workshop
DeJarnette, Fred
07/01/2007 through 06/30/2009
NCSU NC Space Grant Consortium
The National Institute of Aerospace (NIA), NASA Langley Research Center, and Space Grant have conducted four summer workshops for middle and high school educators and now they are planning the 5th workshop for this summer. The first workshop was conducted in 2003 and it involved only middle and high school educators from North Carolina. The second and third years included educators from NC and VA, while the fourth year (2006) added Georgia and Maryland. This year the 5th workshop will also include 12 middle and high school educators each from NC and VA and four each from GA and MD, making a total of 32. The participants are selected competitively by the Space Grant Consortium in each of the four states. Last year (2006) we had 40 applicants from all counties in NC and they were down selected to 12. The educators were all highly qualified and all areas of NC were represented. All four of the previous workshops were highly successful and the word spread to educators throughout the State. Included in the workshops were NC Space Grant presentations and demonstrations. The deadline for applications this year was February 21, 2007 so evaluation of the applicants to down select to 12 from NC is underway. Particular attention is given underrepresented minorities and persons with disabilities. Also, since most of the middle and high school educators are women, recruitment of men is a high priority item. The dates for the two week workshop this summer are one week at NASA Langley Research Center from July 9 to 13 and the second week split between NC State and A&T State July 16-20. The four educators from GA will join the 12 from NC for the second week in NC, while the four from MD will join with the 12 from VA for their second week in VA. NIA provides a stipend of $1,500 to the educators and the Space Grants in NC, VA, GA and MD have been requested by NIA to provide support for personnel and supplies involved in their programs. This proposal requests funding for support of two primary participants from NC State University. We work very closely with Dr. Bill Craft at NC A&T State University, who is submitting a separate proposal.
Space Grant Programs at N C State University
DeJarnette, Fred
03/15/2006 through 03/14/2010
NCSU NC Space Grant Consortium
Last year the NC Space Grant Consortium received an up-grade to Designated State Status. As a result of the increased funding from NASA, NC State University was made an equal partner with the other NC universities in the NC Space Grant Consortium. Prior to last year, NC State University received less funding for local competition and administration than the other universities because the Administrative Staff was at NC State University and the previous director, Dr. Fred DeJarnette, served as both campus Director and Director of the Consortium. Under the new organization, Dr. Chris Brown is the Director of the Consortium and Dr. Fred DeJarnette serves as the Campus Director for NC State University. The Consortium Executive Board approved a budget that provides $20,000 to each NC member University for local competition and administration of Space Grant on their campus. These funds require one-to-one cost sharing. In addition, each member university has the opportunity to receive additional funding in consortium-wide grant competition, which requires one-to-one cost sharing, as well as funds in consortium-wide scholarships and fellowships competition, which do not require cost sharing. The proposal submitted here is a request for $20,0000 for local competition and administration of Space Grant at the NC State University Campus.
PEC Membership Agreement
Dow, Thomas and Garrard, Kenneth
01/01/2008 through 12/31/2010
Lockheed Martin Corp.
Optical Probe Integration For Polaris, Enhancement Project in the Precision Engineering Center
Dow, Thomas; Garrard, Kenneth and Sohn, Alexander
10/01/2007 through 12/31/2009
Johnson & Johnson Vision Care, Inc (formerly Vistakon)
The tasks proposed for this project are: 1. add software to allow probe following on Polaris 2D 2. replace the contacting probe on the Polaris 2D at the PEC with an optical Chromatic Aberration (CA) probe 3. demonstrate the system for 2D measurements 4. extend the capability of that machine to 3D surface measurements (Polaris 3D) 5. demonstrate non-contact 3D measurements of non-rotationally symmetric contact lens molds The goal is to have a 3D measurement system that can measure the figure of an entire arbitrary surface accurately and in a reasonable amount of time. The project will be carried out by faculty and staff at the PEC over a 2-year time period. The user interface developed for the proposed project will be a skeleton version and this project should be followed by the development of user interface by an outside contractor. At the conclusion of this project, the Polaris 3D at the PEC will be loaned to Vistakon for demonstration and development of the user interface. It will be returned to the PEC at the end of this time period. The system at Vistakon will be shipped to the PEC for conversion to the Polaris 3D specifications in a separate project and returned to Vistakon.
Material Effects and Tool Wear in Vibration-Assisted Machining
Dow, Thomas and Scattergood, Ron
03/15/2008 through 02/28/2011
National Science Foundation
This project will show how micrometer-amplitude vibration of the tool can reduce the forces, improve the surface finish and decrease the wear in a diamond turning operation. Vibration Assisted Machining (VAM) was first developed in the 70s and is seeing more commercial applications from grinding of glass optics to diamond turning stainless steel injection molding dies. By selecting the amplitude and frequency of this motion, the tool can separate from the workpiece during the vibration cycle leading to the reported improvements in the machining process. While researchers throughout the world have published papers extolling the virtues of VAM, the results have been empirical and have not addressed the basic science behind such improvements. In this project, the effect of changing the process parameters will be studied within the context of the chemistry and hardness of the workpiece material, the temperature of the tool and chip, the wear of the diamond tool and the surface finish of the machined surface. It will study the process in detail, quantify the improvements in surface finish and tool wear and elucidate the reasons why such improvements are possible. The plan for the research involves three main tasks: 1) 1-4 KHz machining experiments and characterization, 2) analysis and modeling and 3) 20 KHz machining experiments. These tasks will define and corroborate the operating conditions that are required to gain the promised benefits promised and define the best way to produce these conditions.
PEC (Precision Engineering Center) Membership Pool Agreement
Dow, Thomas
07/01/2006 through 06/30/2011
NCSU Precision Engineering Center
PEC Enhancement project "Lexmark Scanning Lens Design"
Dow, Thomas; Garrard, Kenneth and Sohn, Alexander
09/01/2006 through 06/30/2009
Lexmark International, Inc.
Develop laser scanning systems that use Fresnel lenses as the primary focusing components of the beam.
PEC Membership Agreement
Dow, Thomas
07/01/2006 through 06/30/2009
Lexmark International, Inc.
LAT - Live Axis Turning
Dow, Thomas; Eischen, Jeffrey and Buckner, Gregory
04/01/2006 through 09/30/2009
National Science Foundation
The goal of this proposal is to develop a new method to create Non-Rotationally Symmetric (NRS) surfaces that overcomes the limitations of the current techniques and is fast, accurate and inexpensive. Diamond turning (DT) has revolutionized the fabrication of lightweight optical surfaces for defense and science applications such as forward-looking infrared radar and infrared spectrometers. It has made this impact not only because it can accurately and rapidly fabricate diffractive, refractive and reflective optical surfaces, but because it can create reference features tied to the optical surfaces to guarantee optical alignment. An emerging trend in optical design is the use of NRS surfaces that reduce complexity, bulk and weight. To create these surfaces, DT machines have been modified with a low-amplitude Fast Tool Servo, a third axis or a fly-cutter. The problem with the FTS is its limited range and the other techniques are plagued by thermal drift during long fabrication times. The proposed Live Axis Turning (LAT) process combines evolving technologies of air bearings, linear motors, high-resolution encoders and high-speed control systems into a moving lightweight toolpost on a conventional DT machine. The result is a more flexible machine that can increase production and reduce cost for NRS components.
PEC membership agreement
Dow, Thomas
01/01/2004 through 06/30/2009
Minnesota Mining & Manufacturing Co.
Renewal of 3-year membership agreement between the NCSU Precision Engineering Center and 3M.
Computational and Experimental Studies Turbulent Premixed Flame Kernels
Echekki, Tarek
09/01/2008 through 08/31/2011
National Science Foundation
The PI's propose collaborative computational-experimental efforts to understand the mechanisms that govern flame dynamics and structure at lean fuel conditions based on a canonical flame-flow configuration: the post-ignition turbulent premixed flame kernel. Turbulent flame kernels are encountered in spark-ignition engines as well as in other more complex configurations that involve the onset of autoignition in non-homogeneous mixtures or the break-up of turbulent flame structures to form flame pockets. Operation at fuel-lean mixture conditions may result in flame quenching, which may be followed by reignition. It also contributes to thermo-acoustic instabilities, which plague the operation of practical combustion devices operating at lean conditions, such as gas turbines. The combined computational-experimental efforts will address the mechanisms, which govern flame kernel dynamics (inherent instabilities) and structure (local quenching) under turbulent conditions.
An Approach for the Direct Simulation of Subgrid Scale Physics in Fire Simulations
Echekki, Tarek
07/01/2007 through 06/30/2009
NCSU NC Space Grant Consortium
The objective of the proposed effort is to implement a novel modeling framework for subgrid scale physics in coarse-grained simulation of fires. Fires represent a critical factor in the planning of space missions and the design of spacecrafts. The concern for a fire on board a spacecraft becomes even more pressing as longer term space missions are planned around the Earth's orbit (the International Space Station), for manned or unmanned lunar missions and missions to other planets. Key to the mitigation of the effects of fires is the ability to predict them under conditions that are not easy to reproduce on earth-bound laboratories. A principle scope in the present research effort is to develop a reliable predictive tool for fires based on a coarse-grained simulation approach for fluid dynamics and combustion called large-eddy simulations (LES) combined with a direct simulation approach of the physics that is not resolved by LES using a low-dimensional modeling approach called one-dimensional turbulence (ODT). The direct simulation of LES-unresolved non-linear physics is critical to the prediction of fires since the key important processes that govern fire dynamics (e.g. heat release rates, radiation from soot, and chemistry) and emissions reside below the resolution of LES. The ODT model is coupled with a widely used LES code, which was developed by the National Institute of Standards and Technology (NIST), called the Fire Dynamics Simulator (FDS). Interest in developing reliable subgrid scale models for fire physics cuts across a wide range of applications. These include applications of relevance to NASA's space missions; but they also extend to a number of other government agencies. The present project will extend the LES-ODT framework to an important problem in engineering physics, which is the prediction of fires.
Industrial Assessment Center
Eckerlin, Herbert; Terry, Stephen and Leach, James
09/01/2006 through 08/31/2011
US Dept. of Energy
This proposal requests funding from the U.S. Department of Energy to continue and to expand the operation of the Industrial Assessment Center within the Mechanical and Aerospace Engineering Department of NCSU. Each year since 1992 the NCSU IAC has employed about 10 undergraduate and graduate level Mechanical Engineering students. The students and the staff of the IAC visit 25 manufacturing facilities each year and prepare detailed technical reports to the plant managers with recommendations on measures to conserve energy, reduce waste, and improve productivity. We propose to continue the operation of the IAC base center at about the same level of funding for up to five more years. Also we propose to establish a new IAC Specialist Center as an add-on to the IAC base center. The staff of the specialist center will assume a technical and program leadership role on behalf of the IAC program in the area of steam systems.
Computational Simulation of the Joint Expeditionary Collective Protection (JECP) System
Edwards, Jack; Eischen, Jeffrey and Choi, Jung-Il
06/24/2008 through 12/31/2010
Naval Surface Warfare Center (Prime--Defense Threat Reduction Agency)
This project will develop a computational fluid dynamics method for simulating ingress / egess into collective protection equipment being developed for the Joint Expeditionary Collective Protection program. The method will incorporate digital animation technology to replicate mission-specific human activity, will link with urban airflow models to provide external environmental conditions, and will utilize fabric-response structural models to simulate the effects of semi-rigid or flexible entryways.
Numerical Simulation of Multiphase Flows within Scramjet Engine Configurations
Edwards, Jack
04/17/2008 through 04/16/2009
Taitech, Inc (Prime--US Air Force Research Laboratory (AFRL))
This work will continue the development of REACTMB-MP for multiphase flow applications.
A Study of Supersonic Compression Corner Interactions Using Hybrid LES/RANS Models
Edwards, Jack
11/01/2008 through 04/30/2010
Army Research Office
This work will utilize hybrid large-eddy / Reynolds-averaged Navier-Stokes (LES/RANS) models to conduct detailed studies of the structure of supersonic compression-corner interactions. Comparisons with mean-flow and second-moment fluctuation data obtained at Princeton University's Gas Dynamics Lab will be used to assess the performance of the models. Emphasis will also be placed on the mechanisms behind fluctuation amplification, shock system unsteadiness, and mean-flow three-dimensionality for these interactions. The results are expected to provide benchmark quality predictions of these complicated interactions which then may be used to assess simpler closure strategies.
Development of Hybrid Large-Eddy / Reynolds-Averaged Navier-Stokes Methods for High-Speed Internal Flows
Edwards, Jack
01/04/2007 through 01/03/2010
National Aeronautics & Space Administration
This work will develop and test novel hybrid large-eddy / Reynolds-averaged Navier-Stokes methods for simulating three-dimensional, shock-separated flows characteristic of high-speed inlet / isolator / combustor configurations. Objective 1: Further development and refinement of hybrid LES/RANS methods described in [30-34]. This will include construction of improved blending functions that transition properly within the log layer, are suitable for interactions influenced by multiple walls, and that enhance the ability of the hybrid methods to capture both mean and fluctuating fields. Iimproved recycling / rescaling methods that are mesh-independent and that help preserve the proper outer-layer turbulence energy distribution will also be developed, as well as strategies for shifting the closure from RANS to hybrid LES/RANS in a combination flow- and problem (or user)-dependent manner. Objective 2: Use of the developed techniques to simulate well-documented experiments involving crossing-shock interactions [*], normal injection into a supersonic stream [5,36-37] and shock-train propagation [6,*] This will include a detailed assessment of model parameter sensitivity, grid-resolution sensitivity, and boundary condition sensitivity. Objective 3: Implementation of the hybrid LES/RANS models into the state-of-the-art VULCAN Navier-Stokes solver for reacting internal flows and into a next-generation discontinuous Galerkin Navier-Stokes solver developed at the University of Wyoming. The latter will enable a systematic investigation of the effects of higher-order discretization methods on the performance of the model.
Hybrid LES/RANS Simulation of the Effects of Boundary Layer Control Devices Using Immersed Boundary Methods
Edwards, Jack
03/01/2007 through 11/30/2009
US Air Force-Office of Scientific Research (AFOSR)
This work will combine hybrid large-eddy / Reynolds-averaged Navier-Stokes models with immersed-boundary procedures to enable efficient analysis of the effects of different control devices on boundary layer transition and shock / boundary layer interaction control.
Experimental and Numerical Investigation of Two-Phase Flow within Pressure Atomizers Used in Trigger Sprayers
Fang, Tiegang and Edwards, Jack
01/01/2008 through 12/31/2009
MeadWestvaco Corp.
Trigger sprayers are often used in our common life. The liquid atomization behavior dierectly affect the spray quality. The proposed research will conduct experimants on visualization and measurement of droplet size distributions generated by trigger sprayers. At the same time, numerical model will be developed to predict details of the primary atomization process in spraying nozzles to a degree of fidelity suitable for use as initial conditions for other techniques that model secondary breakup and droplet transport.
Development of a Clutch Mechanism for Squirrel Cage Windturbine
Gould, Richard and Tran, Chau
08/09/2008 through 05/15/2009
John Ketcham
The objective of this research is to design and develop one or more clutch mechanisms that are responsive to the rotational speed of squirrel cage windturbine stages. The goal is to demonstrate whether speed sensitive clutches can be used to stage the rotation of stacked squirrel cage impellers in varying wind conditions.
Subscale Flying Wing With Bias Momentum Attitude Stiffening (Task Order No. 6224-NC)
Hall, Charles and Heinzen, Stearns
10/06/2008 through 09/25/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
An Unmanned Aerial System will be develop, construct, ground and flight test the use of an angular momentum wheel for attitude stiffening. The UAS will be composed of a straight wing with a fuselage pod. A removable horizontal stabilizer will be added for the initial flight tests for risk reduction. The UAS will be powered by a electric motor in a pusher configuration. Avionics will be installed for data collection and stability augmentation as required. Analysis of the ground and flight test data will document the use of pitch-roll coupling for a flying wing aircraft.
Investigations of Airworthiness Certification Improvements for U.S. Navy Unmanned Aircraft Systems
Hall, Charles
01/31/2008 through 01/30/2010
Naval Air Systems Command (NAVAIR)
The university will provide focused recommendations for achieving concrete and usable results for improving the standards and procedures for certifying the airworthiness of small Unmanned Aerial Systems (UAS). A Quantitative Airworthiness Scheme will be developed that provides a flexible method for determining inherent airworthiness, compensating airworthiness mitigation techniques, and flight testing techniques. This quantitative scheme will be capable of being used as a design guideline as well as a main component of the airworthiness certification process. It will be flexible enough to cover the full range of UAS sizes and configurations, while being as transparent and easy to use as possible. The QAS terminology and rating system will be based on the terminology used in MIL-STD 882 for risk assessment so that it is already familiar to the user.
Radiative Heating Environment During Planetary Entry
Hassan, Hassan
02/06/2008 through 02/05/2010
National Aeronautics & Space Administration
A number of recent studies have been conducted to evaluate capabilities of existing codes in predicting the aerothermal environment of planetary entry. The focus of these studies was the FIRE II experiment. In general, the various codes gave similar predictions of the convective heating when identical physical models were employed. However, significant differences were noted in predicting the radiative heating especially in the vacuum ultraviolet. The goal of this proposal is to incorporate in the NASA Ames Data-Parallel Line Relaxation (DPLR) a three temperature thermal nonequilibrium model and to update NASA Ames NEQAIR using recent optical data and rates. The validation of this effort will consist of revisiting the FIRE II experiment and comparing with experiments in ground test facilities.
Experimentally Validated Numerical Models of Nanomaterials
Kleinstreuer, Clement and Zhang, Zhe
09/01/2008 through 08/31/2011
National Science Foundation
(a) Objectives: (i) Development and testing of a realistic and accurate computer simulation model for the prediction of engineered nanomaterial transport and deposition in representative respiratory systems of workers, children and seniors. (ii) Construction of validated, easy-to-use correlations of nanomaterial deposition, based on the validated computer modeling results. (iii) Generation of nanomaterial absorption and transport results in tissue needed for physiologically-based pharmacokinetics (PBPK) modeling efforts. (b) Approach: A dual numerical multiphysics approach for obtaining useful nanomaterial deposition results is proposed, considering respiratory system replicas of workers, children and seniors. Transient 3-D computer simulations of: (i) realistic configurations of the upper respiratory tract, and (ii) nasal/oral airways with variable multi-triple bifurcation units, including alveolated ducts, representing the entire respiratory system. Simulation results from task (i) will be thoroughly validated with experimental data sets, while results from approach for task (ii) will be compared to results from (i) and employed to generate an easy-to-use algebraic "lung model" for inhaled nanoparticle deposition. (c) Results: Novel fundamental and applied research results are anticipated. As part of NSF's mission, they foster the understanding of the fate of nanomaterial in human respiratory systems, while the applied results aid in EPA's mission to protect human health and DOE's mission to explore the potentially harmful impact of inhaled nanomaterials produced in the energy sector. Specifically, submodel developments for: (a) three-phase flow of solid nanomaterial, inhaled air, and liquid mucus layer; (b) rod-like nanomaterial transport and deposition; (c) fluid-structure interactions of airflow and bronchial/alveolar-walls; and (d) tissue-uptake of nanomaterial are basic advancements never addressed before in the context of the proposed project. The applied research results include realistic experimentally validated tools for predicting inhaled nanomaterial depositions in three susceptible population groups as well as easy-to-use deposition correlations.
Computational Studies of JP-8 Fuel Aerosol and Toxic Nanomaterial Transport/Deposition in Models of the Human Respiratory System
Kleinstreuer, Clement
08/01/2007 through 11/30/2009
US Air Force
This proposal describes the continuation and extension of our previous AFOSR-contract work on "Multi-scale Computational Analyses of JP-8 Fuel Droplets and Vapor in Human Respiratory Airway Models" (Award No. FA9550-04-1-0422). The results of the first two years (08/01/04-07/31/06) have been documented in 13 journal articles and presented at two conferences and three AFSOR-sponsored workshops. Specifically, employing the validated computer code CFX from Ansys, Inc. (Canonberg, PA) and our proven particle tracking code "F90", the following simulations have been completed: (i) modeling of airflow as well as nano- and micro- particle deposition; (ii) comparison of micro- and nano-size particle deposition in human upper airways, relying on an actual cast model and the Weibel Type A upper bronchi geometries; (iii) studies of multi-component (JP-8 fuel) and/or impure droplet evaporation (or hydroscopicity) and their effects on lung deposition; and (iv) JP-8 fuel vapor deposition in light of variable wall absorption. Key underlying assumptions were aerosol sphericity, smooth rigid airways, and stagnant mucus layer. In the remaining funding year we will simulate and analyze additional lung generations to cover G0 (trachea) to G15 using repeatedly a symmetric triple bifurcation unit (Weibel Type A) and compare results with those obtained with more realistic lung morphologies (after Horsfield/Raabe). Furthermore, lattice-Boltzmann modeling of alveolated bifurcations will be improved and our correlations for global lung deposition assessment will be extended. The new research objectives for 2007-2010 can be grouped into basic and applied studies. The purpose of the proposed fundamental work is to obtain more realistic and accurate local and regional micro/nano-particle deposition data in representative human respiratory systems, covering nose/mouth inhalation and subsequently both conducting and respiratory zones. Of special interest are: the behavior of non-spherical particles, especially Al-oxides heavily used in weapon manufacturing and carbon nanotubes, suspect of high toxicity effects; the impact of distensible walls in the lower lung regions; and the effect of lung morphologies, i.e., considering healthy adults (workers) as well as children and the elderly. With the overall goal being the prediction how much deposits where for any set of air-particle inhalation conditions, the applied studies focus on JP-8 fuel aerosols and nanomaterial transport/deposition in combined nasal and lung airways. Experimentally validated deposition results will be made available in form of local and segmentally averaged concentrations as well as easy-to-use global lung correlations. Measured data sources for computer model validations and simulation of realistic intake scenarios have been provided by AFOSR contractors, the PI's long-term collaborators, as well as the open literature. As in the past, we continue to use the commercial fluid-structure interaction software CFX-ANSYS (Ansys, Inc) but also our in-house finite volume code CFPD (computational fluid particle dynamics), including particle tracker F90, as well as our later in-house code for distensible alveolated bifurcations based on the lattice-Boltzmann method (LBM). Hardware platforms available free-of-charge are NCSU's High-Performance Center (HPC) and the HPC at the Army Research Laboratory (ARL). The expected results, i.e., detailed computer simulations and algebraic global lung deposition correlations, are an integral part of AFOSR's toxicology program (Life Science Division), focusing on JP-8 fuel and nanomaterial. Specifically, given actual inhalation conditions, knowing how much deposits where in the human respiratory system is important for toxicologists, regulators, and health care providers alike.
A Cartesian Mesh Method For Turbulent Flow Simulation
Luo, Hong
07/14/2008 through 06/30/2009
D & P, LLC (Prime--Naval Air Warfare Center)
The objective of the proposed Phase I effort is to develop a prototype Cartesian mesh solver for high Reynolds number turbulent flow simulations. This will be achieved by extending an existing inviscid Cartesian mesh solver with gridless boundary conditions to viscous flow simulations. As a feasibility study, the Phase I outcome will ensure the validity of the proposed Cartesian mesh approach for high Reynolds number turbulent flow simulations.
Development of a Simulation Code for Computing Detonation and Shock Waves on Arbitrary Grids
Luo, Hong
09/24/2008 through 08/15/2009
Engineering and Software System Solutions, Inc. (Prime--US Army Corp of Engineers)
There is a growing need to simulate blast and shock waves for complex geometries on a computer platform in a reasonable time and accuracy. Simulation of high explosive detonation, blast propagation, and shock wave diffraction plays an important role in determining and assessing target vulnerability and weapon lethality in our war against terrorists. Over the course of last decade, significant progress has been made on developing numerical methods for computing shock waves. In general, these numerical methods can be classified by the mesh they use as structured grid methods, unstructured grid methods, and Cartesian grid methods. Each of these methods is advocated, promoted, developed, and used by their respective supporters. Since each method has its own advantages and disadvantages, the answer to which method is preferable depends on the problem to be solved. The structured grid methods1-3 have a disadvantage in mesh generation for complex geometries. The main advantage of the unstructured grid methods4-6 is the ease of grid generation for complex configurations. However, the computational costs and memory requirements are generally higher than their structured grid counterparts. The advantages of the Cartesian grid methods7-9 include ease of grid generation, lower computational storage requirements, and significantly less operational count per cell. However, the main challenge in using Cartesian methods is how to deal with arbitrary boundaries, as the grids are not body-aligned. The cells of a Cartesian mesh near the body can extend through surfaces of boundaries. Accurate means of representing boundary conditions in cells that intersect surfaces are essential for successful Cartesian methods. The objective of the proposed efforts presented in this work is to develop a fast, accurate, and robust method for numerical simulation of compressible flow problems past complex geometries by combining the advantage the efficiency of a Cartesian grid method and the flexibility of an unstructured grid method.
Development of a Regional Structured and Unstructured Grid Simulation Methodology For Propulsion System Analysis
Luo, Hong and Edwards, Jack
01/03/2008 through 01/02/2011
National Aeronautics & Space Administration
Computational Fluid Dynamics (CFD) tools are a key component in the design-validation cycle of the development of the air-breathing propulsion system for the Highly Reliable Reusable Launch System (HRRLS). It is required that the CFD tools provide the predictions of the internal flow field in a propulsion system not only accurately, but also efficiently. NASA's Viscous Upwind Algorithm for Complex Flow Analysis code (VULCAN), a multi-block structured-mesh Navier-Stokes solver for general reactive flows, is considered the state of the art for the numerical simulation of such internal flows. In most cases, structured meshes are near optimal for such systems, but as they become more geometrically complex, the total amount of time required to conduct a tip-to-tail analysis of a new configuration is dominated by the time required to generate a good quality structured mesh. Resolution of large arrays of fuel injector ports, for example, requires the use of fine structured meshes in the vicinity of the injector ports, but other regions (nozzles or straight combustor sections) do not require such fine resolution. To handle such situations economically, VULCAN currently uses a patched-mesh approach that allows non-C0 connectivity across block interfaces. Establishing the proper connectivity is a non-trivial task which greatly increases the time required for setting up a problem, and the patching methods used are not conservative. An alternative to a patching procedure is the use of unstructured, regional meshes that primarily serve to facilitate the transition between structured-mesh regions. As its primary objective, the proposed work develops procedures for incorporating regional unstructured-mesh technology into VULCAN in a manner that preserves all of the original algorithm's components (and efficiency) for structured meshes but greatly increases its flexibility for complex configurations. The unstructured-mesh flow solution module will be based on matrix-free implicit GMRES time-evolution algorithms and will be designed to utilize VULCAN's thermodynamics, turbulence, and chemical kinetics modules, as well as its suite of upwinding methods. The significance of this research is that it provides a method for utilizing unstructured and structured mesh technology where each is the most optimal and most efficient. As structured-mesh regions will be solved using the original VULCAN algorithms, memory and CPU overhead associated with a fully unstructured approach will be minimized. The unstructured "patches" will provide a natural means of ensuring conservation and maintaining ease of mesh generation as well as providing the flexibility to handle complex features within high-speed engines, such as fuel injector ports, cavity flameholders, vortex generators, and other obstructions.
Flame Propagation and Blowout in Hydrocarbon Jets: Experiments to Understand the Stability and Structure of Reaction Zones
Lyons, Kevin
06/01/2008 through 12/31/2009
Army Research Office
Outlined is a proposed research plan for the experimental investigation of flame reaction zone structures. Specifically, the scope of the research will examine fundamental phenomena in a multitude of flame/flow interactions in jets flames: the overall structure of the reaction zone in both laminar and turbulent flames, propagation characteristics, flame hysteretic behavior, blowout/extinction characteristics and effects of air entrainment on reaction zones. The program is designed to be a 3 year research plan, with experiments, data analysis and paper submission throughout the duration of the contract performance. Improved understanding of heterogeneous flame structure and dynamical characteristics are relevant to Army needs. Development of small gas turbines, propagation of flames in-cylinder and extinction/ignition issues in practical devices for optimizing efficiency and engine performance are all served by this research. The intellectual merit of the proposed activity centers on the insight gained into the science of flame stability, structure and propagation. Given the past research of the PI and the current state of the field, investigation of the mode of burning at the leading-edge of reaction zones is likely to produce results with the potential for significant impact for Army interests. The broader impacts of the research lie in the potential for improved performance of combustion devices in terms of stability and efficiency. The data obtained from studies like the ones proposed can help modify computational design approaches in the engine industry. These designers increasingly rely on computational models in their design protocols, but require experimental input for validation. Moreover, an improved understanding of physics of flame stabilization can potentially inspire novel designs of turbines and combustors. Ph.D. students who work on this type of research find employment in defense and aerospace companies and academia, as well as at national laboratories. Students (Grad and Undergrad) will be actively involved in this experimental research.
Development of a Space Systems Design Teaching Manual
Mazzoleni, Andre
01/01/2009 through 05/15/2009
NCSU NC Space Grant Consortium (Prime--National Aeronautics & Space Administration)
In order to provide students with exposure to topics relative to space, space systems design, and systems engineering, the MAE Department has been developing a Space Systems Design capstone course offered to seniors majoring in Aerospace Engineering. In completing the Space Systems Design course, students design, build, and test Earth-based demonstration hardware intended to mimic space-based systems. In the process of developing the course, the course instructors have developed a large amount of material that is uniquely suited to the Space Systems Design course at NCSU. Due to the upcoming graduation of the current course teaching assistant and because of the need to provide a sense of continuity to the course, the project proposed herein involves the development of a Teaching Assistant Manual for the Space Systems Design course. In completing this project, we will develop a manual consisting of notes regarding basic class procedures, formal lectures given during the course, exercises developed for use in the course, and other course materials. The intention is for the information gathered through practice over the last 5 years of teaching the course be passed down to future teaching assistants to assist with the course. Much of the institutional knowledge of how to run the Space Systems Design course that exists in the MAE Department has been cultivated by evaluating which methods work well for students and which methods don't work well for students. Codifying the lessons learned during this process and the general course pedagogy will provide an invaluable stepping stone for those assisting with the course in the future; the best way to accomplish this codification is through the development of the proposed Teaching Assistant manual.
Development of Air Table Facility for Space Systems Senior Design Program
Mazzoleni, Andre
07/01/2008 through 06/30/2009
NCSU NC Space Grant Consortium
Air tables are invaluable tools for conducting table-top experiments involving the design of spacecraft control systems. With an air table, 2-degree-of-freedom satellite motion can be simulated by floating spacecraft mock-ups on a cushion of air, enabling students towo test out differnet mechanisms for controlling spacecraft motion. This proposal requests funds for the 2009-2009 space Senior Design class program to support the design and construction the air table facility described above.
Mars Rover Technology Development
Mazzoleni, Andre
NCSU NC Space Grant Consortium
11/21/2007 through 05/31/2009
New Mars rover technologies are needed for NASA's proposed exploration plans for Mars. this project will involve developing spherical-type ("Tumbleweed") rovers and technologies for enabling Martian rovers to drill beneath the Martian surface. One of the new technologies for the rovers that will be developed is the ability to be self-propelled, i.e. to roll even when winds are light.
Structural Design of Inflatable Atmospheric Entry Systems (NIA GRA For Rafael Lugo)
Mazzoleni, Andre
08/15/2007 through 08/14/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
This project, supported by NASA-Langley, concerns the development of inflatable systems for entry descent and landing flight systems. Specifically this project will involve structural design and non-linear structural analysis of inflatables used in high heating, atmospheric entry systems.
Development of Drop Tower Facility for Space Systems Senior Design Course
Mazzoleni, Andre
07/01/2007 through 06/30/2009
NCSU NC Space Grant Consortium
The Aerospace Engineering program at NC State requires all students to take a two-semester course in aerospace systems design and select either aircraft design or space systems design. The enrollment in the space systems design course has increased from 7 students last year ago to 17 this year, and we anticipate that the numbers for next year will be similar to this year. To ensure that there is a variety of projects for students to select from, this proposal requestes funds to develop a drop tower facility that students can use to test future projects in a reduced gravity environment.
Investigation of Intervertebral Stabilizer Selection Criteria For Long Spinal Fusions With Variable Spinal Stiffness
Mazzoleni, Andre
08/16/2007 through 08/31/2009
Synthes Spine Company, LP
About 10 million adult patients suffer from severe back pain that can be reduced or eliminated through spinal surgery (www.brainandspineonline.com). Significant technical advances have been made over the past few years, but long spinal fusions still pose a significant challenge because of poor bone quality, complex local anatomy and special biomechanical conditions at the lumbosacral region . Currently the most widely used techniques use external rods which are aligned parallel to the spinal column and are attached to each vertebra with pedicle screws to provide the required stability and support when fusing multiple intervertebral levels. Spine stability is a critical aspect before and after spinal fusion, and spine stability is directly proportional to intervertebral joint stiffness (Quint, U). Insufficient intervertebral joint stiffness can be corrected by using stabilizing spacers to replace the destabilizing intervertebral discs, but determining which stiffness levels are destabilizing enough to require additional hardware is currently more art than science. Current successfully used implants include the ALIF and TLIF spacers. Having firm criteria to aid in the decision of whether or not to incorporate additional stability to the spine by inserting spacers during a spinal fusion procedure could lead to more effective outcomes and reduce the risks of postoperative complications due to spinal instability, hardware failure or further degeneration.
Flight System Identification of Spacecraft (NIA GRA Chris Hartman)
Mazzoleni, Andre
05/31/2006 through 05/31/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The research area involves practical application of system identification to spacecraft operating in the atmosphere. The graduate student will participate in the Exploration sponsored flight experiment designed to quantify the CEV launch abort scenarios. Data will be collected from flights of CEV models. The student will utilize system identification methods to recover aerodynamic properties of the models over a Mach number range. System identification is the mathematical modeling of dynamic physical systems based on measured data from an experiment, and includes experiment design for data collection, conducting flight experiments, flight dynamics, data analysis, modeling, simulation, and model validation using data from additional experiments. Future sponsorship is expected from either CEV or Mars robotic exploration. The student will be advised by Dr. Mazzoleni of NCSU. The NASA POC is Dr. Gene Morelli.
High-Resolution Simulation and Modeling of Atmospheric Turbulence
McRae, David and Hassan, Hassan
04/19/2007 through 03/19/2010
NorthWest Research Associates (NWRA) (Prime--US Army)
This project will modify the well developed mesoscale atmospheric model WRF-ARW by installing the NCSU adaptive mesh algorithm DSAGA, the NCSU k-zeta turbulence model, and a NWRA developed BHM SGS model with the goal of high resolution prediction and simulation of atmospheric turbulence. Other modifications will be installed as determined by analysis of the model and its output. Verification and validation of the high resolution model and integration into a suite of prediction tools will be conducted in concert with NWRA. Code development and maintenance will be conducted jointly with NWRA leading to a single product. NCSU will provide support during delivery and checkout of the code.
Formulation Of Environmentally Friendly Lubricants Based On Polymeric Materials For Cold Forging Processes
Ngaile, Gracious
07/01/2006 through 06/30/2009
SISU Chemicals LLC (Prime--National Science Foundation)
The forging industry in North America accounts for $6 billion in sales of forged parts per year. Cold forged parts account of about half of these sales, which serve among other sectors, the automotive, ordinance, general industrial equipment, and aerospace industry. In recent years the U.S. forging industry has undergone significant shrinkage associated with intense global competition, technological changes, and environmental and economical factors. Thus, the tonnage of U.S. forged parts has steadily been declining over the years due to the importing of forged parts from overseas where the manufacturing cost is lower. There is a great concern that the current lubrication system for cold forging based on zinc phosphate coatings will eventually be phased out as the lubricant caries serious environmental concerns. Without a suitable alternative, phasing out of this lubricant will have drastic consequences on the already ailing U.S. manufacturing industry. Results from Phase I has proved that the developed polymeric lubricant can perform equally well as compared to zinc phosphate coating, especially, under medium forging operation. The main objectives of Phase II are to continue to refined variants of the polymeric lubricant to suit various severities of deformation and develop a scale-up system for producing large quantities of lubricants for field testing. The new environmentally friendly lubricants are conceived by emulsion polymerization. The lubricants are formulated based on combination of internally stabilized emulsion polymers combined with advances in adhesion chemistry and synthetic lubricants. This lubricant is aimed at replacing zinc phosphate coating lubrication system. The effort will include development of a quick and robust online lubrication system for the newly formulated lubricants with a goal of commercializing the lubrication system.
Career: Meso and Macro Hydroforming of Complex Shapes-Mechanics and Control
Ngaile, Gracious
02/01/2005 through 01/31/2010
National Science Foundation
PROJECT SUMMARY CAREER: MESO AND MACRO HYDROFORMING OF COMPLEX SHAPES - MECHANICS AND CONTROL Hydroforming is an innovative method with a potential to form parts of various geometric complexities from tube or sheet materials using pressurized fluid as a soft die. The process has numerous advantages over stamping including, high strength to weight ratio, part consolidation, accuracy, improved stiffness, reduced scrap rate, design flexibility etc. Presently, the impact of this technology is in the automotive and aerospace industry as evidenced by the rapid growth in recent years, e.g. in 2001 hydroforming sales went as high as $1.9 billion in North America alone and sales are expected to rise by 20 percent in 2004. Despite the technological advancements, the fundamental understanding of the mechanics of the hydroforming process is inadequate. This has hindered optimal utilization of this process in areas such as hydroforming of complex shapes, hard to form materials, hydroforming of thin hollow sections etc. Furthermore, due to inadequate R & D work on hydroforming in the U.S. and rare formal hydroforming education, the U.S. based companies that produce hydroforming systems are very few making the U.S. highly dependent on importing this technology from overseas. Of equal importance, the limited knowledge of the process has confined this technology to macro hydroforming, despite the apparent potentials this technology may have in meso hydroforming. This new frontier may have enormous impact in the manufacturing of miniature devices with intricate hollow shapes. To meet these challenges, this career proposal has the following major objectives: a) Advance research in macro-hydroforming of complex shapes: Study the fundamental mechanics of the hydroforming process to enable hydroforming of complex shapes through innovative non-conventional means of synchronizing the hydraulic fluid pressure and feeding of material as prescribed in time domain. b) Promote research in meso-hydroforming: Study the fundamental mechanics of meso-hydroforming and establish a knowledge base to enable manufacturing of miniature parts with intricate internal features. c) Provide students with the opportunity to acquire a multidisciplinary education: Provide an in-depth understanding of system components of meso and macro hydroforming and their interrelationships such that students function well as engineers in the competitive global market economy and, d) Promote interinstitutional research and educational collaboration: Strategically establish a dynamic link between selected institutions from both the U.S. and overseas aimed at complementing, advancing, and opening new research frontiers in hydroforming, including opening inter-institutional education manufacturing programs to prepare students in the competitive global market economy.
Collaborative Research: Full-spectral Interrogation of Fiber Bragg Grating Sensors for Damage Identification
Peters, Kara Jo and Zikry, Mohammed
05/01/2009 through 04/30/2012
National Science Foundation
The proposed research plan will fundamentally change the method in which fiber Bragg grating sensors are applied for damage identification and structural health monitoring in heterogeneous material systems. This will be achieved by both extending the data acquisition rate for full-spectral interrogation of fiber Bragg grating sensors through a MEMs tunable filter interrogator and deriving signal processing algorithms for both in-situ damage identification and structural health monitoring applications. The research plan is a collaborative effort between researchers in the Mechanical and Aerospace Department at North Carolina State University and the Department of Electrical and Computer Engineering at Brigham Young University.
Self-Healing Sandwich Composites
Peters, Kara Jo and Zikry, Mohammed
08/01/2008 through 07/31/2011
National Science Foundation
The major aim of the proposed research is the development of a sensor network and sandwich composite structural system that can self-repair after extreme events, such as multiple impacts. The sensor network will capture the state of the local host structure prior to and post self-healing. The success of this research project would provide for reliable structural systems that can be applied at critical structural locations that are susceptible to extensive failure. Furthermore, a multi-physics predictive computational model of the entire process that would integrate the processes of photopolymerization, lightwave propagation in a heterogeneous structure, opto-mechanical interactions, and thin film polymer damage mechanics will be developed for optimization and lifetime predictions of the structural system.
Intelligent Multi-Scale Sensing for Damage Identification and Mitigation in Woven Composite for Aerospace Structural Applications
Peters, Kara Jo and Zikry, Mohammed
US Air Force-Office of Scientific Research (AFOSR)
01/15/2008 through 11/30/2009
This proposal has as its major aim the development of an integrated analytical, computational and experimental investigation of material deformation, damage, and failure modes in heterogeneous material systems embedded with combinations of optical sensor for a detailed understanding and control of the dominant thermo-mechanical mechanisms that characterize failure occurring over different physical scales. The optimally distributed and embedded fiber optic sensors will provide displacement, displacement gradient fields, and strains at different physical and temporal scales. Concurrently, the sensors will provide functional self-testing to evaluate the validity of each measurement based on their integrity. Relating these local strain measurements both during and post-failure events to global measurements of material behavior, such as contact forces and dissipated energies, will provide a comprehensive understanding and prediction of failure not previously obtained by the scientific and engineering communities. This will result in effective life cycle predictions that will be based on interrelated material mechanisms, as opposed to current estimates based on inadequate strain-field distributions.
Processing And Characterization Of Functionally Graded Coatings For Bio-Medical Implants
Rabiei, Afsaneh and Cuomo, Jerome
05/01/2006 through 04/30/2010
National Science Foundation
The aim of this study is to develop a functionally graded Hydroxyapatite (FGHA) coating for orthopedic and dental implants with a tailored release rate of an antimicrobial component such as silver ions. Infection has been one of the main concerns for implant surgery. As the oral antibacterial medicine may affect the total body, while the surgery area is the only place that need the medication, there has been some studies on antimicrobial/ antibacterial loaded bone cement for cemented implants. However, for cementless implants that include the Hydroxyapatite (HA) coatings, there has not been an effective antimicrobial loading technique offered yet. It has been shown that small amounts of silver ions can have a good antimicrobial effect on polymer and diamond like carbon (DLC) with no toxicity. However, the incorporation of antimicrobial components such as silver ions into HA and most importantly to FGHA coatings has not been studied. As our graded crystallinity HA coating has a gradual release rate, incorporation of it with antimicrobial elements such as silver ions can cause a gradual release of antimicrobial component as well. In this case, the antimicrobial component will have a higher release rate along with the highly amorphous layer at the top surface of the film right after surgery and it's release rate will be gradually decreased through the thickness of the film towards the more crystalline layers. This can provide a lifetime antimicrobial effect on the implant at the same time the graded crystallinity will provide a great osseointegration and mechanical property of the coating. Furthermore, the proposal aims to increase the service-life of an orthopedic/ dental implant by creating coatings that form a strong, long lasting, bond not only with the juxtaposed bone, but also with the metal substrate. As the result, a patient who has received joint or dental replacement surgery can return to a normal active lifestyle with less risk for infection and less need for oral antibiotics or revision surgery. The proposed education plan involves four complementary initiatives. This research has an interdisciplinary nature based on collaboration between MAE and MSE departments at NCSU with the University of Tennessee. The students will have the opportunity to work and learn more from all parties involved in this research. The PI will continue developing her new graduate course on Advanced Materials, including Biomaterials. This course has been developed and taught by the PI for a few times. Undergraduate students will continue their involvement in this research through both REU supplement and undergraduate Independent Research Project course. Graduate students will be involved in coordinating the undergraduate research. Currently there are four graduate and three undergraduate students working in PI's group. Two graduate and one undergraduate students are specifically focused on this research. Each graduate student is teamed up with an undergraduate student. This will contribute to the integration of undergraduate and graduate education. The final effort will be on special attempts to recruit underrepresented and/or female student. Being a female faculty the PI has been a role model for female students and she has a track record on hiring female and disabled students in her group. Currently there is a female UG student that has been supported through an REU supplement to this project and a female PhD student who is actively working on the PI's NSF CAREER award. The proposed study investigates a new coating material with tailored dissolution rate that can match with bone growth together with gradually released antimicrobial components that can have a great impact on the development of the next generation of orthopedic and dental implants with improved durability, along with better biological responses.
A Computational Mechanics Model for the Simulation of Creping Process
Ramasubramanian, Melur
12/01/2007 through 11/30/2010
Procter & Gamble Co.
The objective of this research is to develop a computational mechanics model for simulating the creping process. The computational model will be developed based on a fundamental understanding of the creping process through analytical and experimental studies. Creping process is used to produce lowdensity paper grades whether the basic structure is a flat sheet or patterned sheet, whether the sheet is through-air-dried (TAD) or conventional wet pressed (CWP). While the tissue sheet structure is reasonably well-characterized and a satisfactory micromechanics model for paper as material for use in computational codes is available, the creping process itself is not well understood. There are some empirical observations on the process that are available. Through this proposed work, the creping process will be described mathematically, and modeled using analytical and finite element modeling approaches, and verified with experimental data. Advantages of this approach include rapid simulation of the effects of changing raw material properties, sheet structure, process parameters, and creping conditions, on the resulting creped structure and its performance characteristics. This approach has the potential to substantially reduce the time spent in pilot plant and mills experimentally trying various ideas and concepts for new product development and process improvements.
Simulation of Unsteady Reacting Flows in Pulsejets with Ejectors
Roberts, William and Kuznetsov, Andrey
06/01/2008 through 09/30/2009
Ohio Aerospace Institute (Prime--National Aeronautics & Space Administration)
Augmentors/ejectors are completely passive devices downstream of the propulsion system exhaust and offer the potential to increase the thrust and specific impulse of unsteady propulsive engines by as much as 75%. This is achieved by capturing the starting vortex emitted from the exhaust duct and the resulting entrained fluid. This increases the effective mass flux, at the expense of effective velocity, resulting in higher thrust and better fuel efficiency. There have been a number of experimental and computational studies on augmentors for both pulsejets (subsonic exit velocity) and PDEs (supersonic exit velocity) by Krothapolli at FSU, Paxson at NASA Glenn, and Gutmark at Cincinnati, to name a few. Much of the early experimental work with pulsejet + augmentor combinations was carried out by R. Lockwood while at the Hiller Aircraft Company in the 1960's. However, there is still considerable room for optimization of the augmentor geometry.
High-Value Transportation Biofuels From North Carolina Feedstocks
Roberts, William; Lamb, Henry and Stikeleather, Larry
06/30/2008 through 07/01/2009
Biofuels Center of North Carolina
The quest for liquid transportation fuels derived from bio-renewable resources (biofuels) has captured the attention of the nation and the world because of escalating petroleum costs and environmental concerns with the consumption of fossil fuels (e.g., global climate change). Currently, there is heavy emphasis on ethanol and biodiesel production in the U.S., with ethanol capacity approaching 6.2 billion gallons annually and biodiesel capacity approaching 300 million gallons annually. While these biofuels have enjoyed some commercial success, they do have a number of shortcomings. These "first generation" biofuels are typically tied to a single feedstock, resulting in reliance on a single agricultural commodity. Another problem is that the chemical, physical, and combustion properties ethanol and biodiesel (Fatty Acid Methyl Esters, FAME) differ very significantly from their petroleum-derived counterparts, causing causes many operational difficulties. Ethanol, due to its hydroscopic nature, readily absorbs water and thus must be distributed throughout the US via truck or rail rather than through the existing pipeline infrastructure, significantly raising its cost and decreasing its "greenness". Ethanol also cannot be used in unmodified gasoline engines and has considerably lower energy density than gasoline, resulting in a reduction in fuel economy and vehicle range. Biodiesel has a lower energy density than petroleum diesel and has a cloud point around 0 ¢ªC, creating obvious cold-flow problems for winter operation. To mitigate these issues, we have invented a unique multi-step process (covered by three provisional patents) to convert virtually any triglyceride feedstock, from crop oils (both virgin and waste) to animal fats (from chickens to cattle) into a biofuel that has virtually identical chemical and physical properties to the petroleum fuel it is replacing. These 'second generation' biofuels do not have any of the drawbacks of the current first generation biofuels. In addition to true biogasoline and a second generation biodiesel, this process is capable of producing an aviation fuel that will be fully compliant with DoD and FAA fuel specs. The market for jet fuel is approximately 40 billion gallons annually (the US Air Force is currently spending $10M/day on JP-8!). The DoD is moving towards a single strategic fuel, replacing Diesel Fuel #2 with JP-8. Thus, it is expected that the demand for jet fuels will continually increase.
Equipment Grant for GC-FID/TCD to Measure Species Concentrations in High-pressure Flames
Roberts, William
06/01/2008 through 05/31/2009
Army Research Office
This proposal is being submitted to secure funding to acquire a gas chromatograph with two detectors to allow the measurement of soot precursor species in high-pressure flames. The DoD is interested in soot mitigation strategies for both human health and reduction of IR tracking susceptibility. Diesel and gas turbine engines operate at high pressure to increase thermal efficiency. However, the majority of experimental investigations of soot formation have occurred in atmospheric, or even sub-atmospheric flames. The PI's research group is one of the few groups that have the capability to operate and investigate high-pressure diffusion flames, in both a co-flow and counter-flow geometry. These flames currently operate on gaseous fuels (ethylene primarily), but could be modified to prevaporize liquid fuels such as JP-8 and DF-2. To date, measurements have concentrated on soot volume fraction and soot surface temperature. Recently, measurements of species concentrations up to C-14 molecules, has begun. Unfortunately, intrusively gathered samples are extracted from the flames and then transported to the EPA for analysis. This is a both very time consuming and expensive. It also relies on the good will of the analytical chemists at the EPA. It would be very beneficial to have this analytical chemistry capability residing locally with the experimental apparatus and under direct control of the PI.
Constitutive Modeling of Shape Memory Alloys (SMA) (Task Order No. 6219-NC)
Seelecke, Stefan
09/08/2008 through 07/31/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The objective of the proposed work is a comparative study of several available shape memory alloy (SMA) models in order to assess their suitability for the simulation of adaptive structural aerospace components. A number of advanced components are currently being investigated, such as the SMA torque-tube system developed by Boeing to control the trailing edge of aircraft wings or the SMA-actuated chevron system developed by NASA Langley, which is intended to minimize jet noise. In regard to the simulation of such adaptive structural systems, standard finite element (FE) codes to date do not provide the tools to account for the coupled thermo-mechanical behavior of SMA actuators, and it is the objective of the current project to assess the state of the art of constitutive models and analyze their suitability for implementation into the most popular FE codes.
Experimental Characterization of Electro-Active Pumping System
Seelecke, Stefan
08/01/2008 through 06/30/2009
Parker Hannifin BioCare
The Adaptive Structures Lab (ASL) at North Carolina State University will perform a series of experiments with novel electro-active-polymer-based (EAP) pumping devices recently developed by Parker Hannifin's BioCare Division. It is the goal to characterize the electromechanical performance of these devices as well as their fatigue and failure behavior in order to develop reliable design guidelines and operation limits for future applications.
Principles of Autonomous Soaring
Silverberg, Lawrence
01/01/2009 through 12/31/2009
Naval Research Laboratory (Prime--US Navy-Office Of Naval Research)
This effort builds on Dan Edwards' pioneering studies into the feasibility of autonomous soaring and other ongoing efforts that he is undertaking to lay a foundation in autonomous soaring. Through this grant, the results will be documented in a seminal paper to appear in the AIAA Journal of Aircraft. The paper will address, among the different topics, the basics of thermal sensing and centering algorithms, speed optimization, system implementation details, and flight testing results.
Real-Time Synthesis of Unsteady Hydrodynamic Loads from Measurements on the Hull Surface
Silverberg, Lawrence
05/01/2006 through 12/31/2009
US Navy-Office Of Naval Research
The goal of the proposed work is to develop a method to synthesize, in real-time, unsteady resultant forces and moments from measurements over the surface of a submarine hull. More specifically, the following questions will be addressed in the work: (1) Can we obtain the forces and moments experienced by a submarine in unsteady flow from sensors placed on the hull? (2) How does the correlation between force/moment and stagnation/separation point with 2-dimensional bodies, which has been demonstrated in the literature, extend to 3-dimesional bodies, which has not yet been investigated? (3) Can the technique of modal filters, which has had success in distributed sensing of structural vibrations, be used in the force/moment and stagnation point/separation point correlation? (4) Is there a simple relationship between the attainable resolution of forces/moments and the number of sensors used on the body? (5) If so, what is this relationship? (6) Will this method of sensing unsteady fluid forces and moments be useful in non-body of revolution submarine design and/or real-time submarine control?
Graduate Student Advisement
Tolson, Robert
08/11/2008 through 08/15/2010
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The basic research project supports the Structural Dynamics Branch at NASA in the research area concerning the creation and application of uncertainty estimation of data generated during test programs. An example of potential research would be the development of an uncertainty algorithm that identifies the probability distribution of a set of wind tunnel results taken of an ARES wind tunnel model. Another example is the creation of an uncertainty model for the results of an airbag support drop test of a simulated crew module. As part of this effort Dr. Paul Cooper will advise the research of GRA-Matt Hoover.
Subsonic Fixed Wing Research
Tolson, Robert and Cooper, Paul
08/11/2008 through 08/10/2010
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
This research project supports the Subsonic Fixed Wing program and involves tailoring a hybrid wing aircraft to adapt during flight to reduce drag while maintaining a low weight. Passive tailoring where the loading twists the wing to an aerodynamically more desirable shape and active tailoring where actuators could be used to deform the wing will be considered. Analytical investigation will involve commercial computer codes, and additional code development may be needed. The research will be conducted at NASA Langley Research Center utilizing a hybrid wing vehicle global model developed by industry and will utilize load and deformation data obtained within Langley or from industry partners. Paul Cooper will advise GRA-Seyed-Hossain Mousavi in collaboration with Dr. Robert Tolson.
NIA Foundation Grant Activity 3520-NC
Tolson, Robert
10/01/2008 through 09/30/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
Experimental Data Uncertainty Estimation (NIA GRA Matt Hoover)
Tolson, Robert
08/16/2008 through 08/15/2010
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The area of research is supported in the Structural Dynamics Branch and addresses the creation and application of uncertainty estimation for data generated during test programs at NASA. An example might be the development of an uncertainty algorithm that identifies the probability distribution of a set of wind tunnel results taken of an ARES wind tunnel model. Another example just completed by Dr. Horta, the principal investigator in this area, is the creation of an uncertainty model for the results of an airbag support drop test of a simulated crew module
Planetary Flight Systems (NIA-GRA David Busnardo)
Tolson, Robert
07/21/2008 through 12/05/2008
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The research performed by this GRA student will be on topics related the LaRC Strategic Goal 3, "Characterization and Traversal of Planetary Atmospheres." He will participate in the research program focused on aero-assisted missions that perform aerobraking, aerocapture, EDL or sustained flight through planetary atmospheres or precision landing technology. The research may include system design trades studies for future missions like Mars Sample Return, Mars Lander Network, Venus In-Situ Explorer, Titan Explorer, etc. Alternately, the research may be on near-term high payoff technologies like precision landing using large-area hypersonic drag devices (inflatables), mid-term technologies like propulsive hypersonic descent, high L/D hypersonic aeroshells, characterizing planetary atmospheres for aeroassist missions, or precision landing and hazard avoidance.
Mars Science Laboratory Research (Task Order No. 6233-NC)
Tolson, Robert
09/22/2008 through 09/25/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The Mars Science Laboratory (MSL) will be launched in September, 2009 and arrive at Mars the following summer. MSL is the first mission where sophisticated Mars mesoscale atmospheric models (SWRI & OSU) play a critical role in the entry, descent and landing (EDL) spacecraft and mission design. In addition to diurnal variations, for which the models provide the day to day variation, there is vertical structure in temperature and density, generally due to gravity waves, in the 10 to 30 altitude range of interest to EDL. Validation of the model predicted wave structure is important to reduce risk for the overall mission. However, there are limited data sets to perform such validation. The largest data set is the MGS TES data, but these sounding only have a 5 km resolution in the vertical. A second data source is the MGS radio occultation data set which provides vertical resolution of a kilometer while averaging along the radio path. These data are the most likely to provide some indication of gravity wave activity for model validation.
Subsonic Fixed Wing Research (NIA GRA Seyed-Hossain Mousavi)
Tolson, Robert
08/11/2008 through 08/10/2010
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
This research, which is part of the subsonic fixed wing project, involves both experimentation and analytical approached to developing and maturing technology aimed at producing lightweight structures for hybrid-wing-body and other aircraft. The project includes the development, application and validation of analytical methods for airplane design. New concepts in structural design such as unconventional cross sections, new manufacturing methods, and adaptive tailored structures are considered. The research will be conducted at NASA Langley.
Laser-Based Planetary Landing System Analysis (GRA Matthew Aitken)
Tolson, Robert
05/19/2008 through 05/18/2010
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
This research project involves the development and validation of methods for the application of laser-based systems to enable landing on the Moon and planetary surfaces. The research will address integrated systems that measure altitude, velocity, hazards in the landing area, and provide terrain relative navigation. The research will be conducted at NASA Langley and will utilize data from numerous laboratory and field test of the ALHAT system and components.
Flight Mechanics Research for Earth and Planetary Missions (NIA GRA for J. Gaebler and J. Fuller)
Tolson, Robert
08/15/2007 through 08/14/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The research will cover design, analysis and simulation of CEV entry, manned and unmanned lunar missions, and planetary mission aeroassist studies. The research will include flight mechanics design trades, evaluating various spacecraft control algorithms, determining the effect of parachute aerodynamics and dynamics, evaluating the effect of environmental variations on atmospheric flight, precision landing capability, and overall vehicle performance. The research will include 3-DOF, 6-DOF and multi-DOF trajectory and Monte Carlo simulations. Aerothermodynamic studies will include aeroassist phases of various missions to develop the flight trajectories, the guidance, navigation and control system, and for use in defining the vehicle thermal protection system.
Statistical Methods For Intelligent Data Integration (SMIDI)
Tolson, Robert
01/01/2008 through 12/31/2010
National Aeronautics & Space Administration
Statistical Methods for Intelligent Data Integration (SMIDI) Aerodynamic data for hypersonic vehicles are derived from many sources including wind tunnels, ballistic ranges, full and scale model flight test, CFD, etc. The data are presented in numerous forms, for example, aerodynamic static and dynamic force and moment coefficients, pressure distributions, trajectories, orientation, etc. These data usually cover different ranges of Mach and Reynolds number, vehicle dynamics, orientations and rates and have various level of accuracy. The objective of this research is to develop methods for combining these data into a single data base that characterizes the statistically "best" estimate of the aerodynamics. A numerical tool will be developed that includes these methods and the tool will be validated and demonstrated on a multi-source data set like the CEV. A minimum variance estimation process will be developed to estimate a parameterized aerodynamic model. Well developed methods for estimating model uncertainty as a function of the independent variables can identify regions where additional data are required. The effects of data noise, data biases, and un-estimated parameters will be evaluated in a rigorous statistical manner. The resulting tool will provide a method of combining multi-source and multi-accuracy data to arrive at (1) an easy to use aerodynamic data base with quantified errors, (2) a tool to aid in designing future aerodynamic test and (3) a tool for identifying strength and weaknesses of specific data sources.
Obtaining Winds and High Altitude Density Profiles from MRO Accelerometer Data
Tolson, Robert
03/06/2007 through 06/30/2009
California Institute of Technology - Jet Propulsion Laboratory (NASA) (Prime--National Aeronautics & Space Administration)
The purpose of this study is to produce both new as well as improved mission data products from the Atmospheric Structure Facility (ASF) Investigation that will significantly enhance the scientific value of the ASF investigations to: 1. Characterize the Mars' global atmospheric structure and transport. 2. Characterize the Martian uppper atmosphere in grater detail. 3. Improve atmospheric modeling capabilities for future mission to Mars.
Samuel P. Langley Distinguished Professor Program (LAP)
Tolson, Robert and DeJarnette, Fred
01/01/2005 through 09/25/2012
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
North Carolina State University is actively recruiting a faculty member to serve as the NIA Langley Professor. That position is to be filled ASAP, but no later than December 31, 2004. This proposal provides a generic job description involving leading a research effort, teaching, student advising, and a budget for the period January 1, 2005 through December 31, 2005. The proposal requests $400,000 funding from NIA with $172,673 cost sharing provided by NC State University. Included in the budget is a salary for the Langley Professor, release time and summer salary for the Liaison Professor (Dr. Fred R. DeJarnette), travel, communications,research supplies, two-competitive faculty grants, support for four graduate students, and on-campus indirect costs. The Langley Professor is to spend approximately two-thirds of the year at the NIA in Hampton, VA and the other one-third at NCSU.
SGER: Synergistic and Inherently Stable Laser/Plasma-Jet Welding Processes: Proof of Concept
Tu, Juei and Gremaud, Pierre
09/15/2007 through 08/31/2009
National Science Foundation
Laser based manufacturing is a technology capable of drastically increasing productivity while reducing production cost. Laser welding of various materials of limited thickness (under 10 mm) has become a standard production in industry. Applications to heavy industry (shipyards, trucks, heavy machinery, etc) require deep laser welding from 10 mm to 30 mm or beyond. This has proved to be challenging because of the prohibitive cost of very high power laser systems and instability of the deep penetration welding process. Intellectual merits: To date, in spite of many attempts made to increase the stability of high power laser welding, only modest improvements under specific test conditions have been observed. This lack of success results from the use of essentially open-loop approaches which in turn comes from the lack of reliable real time sensor data about key process information. The inherent instability of the high power welding process compounds those difficulties. This SGER proposal aims at developing a pilot system to achieve synergistic and stable deep penetration welding by combining a fiber laser and a plasma jet. The success of this pilot system heavily relies on a real-time plasma sensor and the integration of the fiber laser and the plasma jet. To develop this real-time plasma sensor, we propose to acquire a high speed photography system together with a high performance computing system for image processing at a frame rate up to 200,000 fps. This high speed photography system allows the PIs to observe the oscillation of keyhole and plasma ejection in order to validate and refine the design of the proposed plasma sensor array. The observation also allows the validation of rigorous mathematical modeling of the laser/plasma-jet process currently under development. The second acquisition is a 3kW plasma-jet system to be integrated with a 300W single-mode fiber laser to form the proposed pilot system. The key technology resides in synergistic energy deposition of a laser beam with moderate power and a plasma torch with a special nozzle design. The laser, with its much higher power density, will create the keyhole while a finely focused plasma jet from the plasma torch will provide additional energy deposition. The keyhole will be stabilized through active regulation of the plasma jet and the laser-induced plasma. The successful development of closed-loop deep penetration laser welding processes will be a breakthrough in this area. The request SGER grant will allow the PIs to prove the synergistic energy deposition concept as well as the inherent stability of the proposed process, thus, establishing the foundation for a closed-loop welding system. Such a closed-loop system has not been attempted because the lack of real-time feedback sensors. Broader Impact: The proposed technology will render laser welding economically viable for a much larger range of industries. The US industry is in need of this kind of advanced technology to boost competitiveness in order to turn back the tide of off-shoring jobs by many major corporations. Further, US laser job shops (over 10,000) will see their service capability significantly increased by the availability of such a technology. Computationally, the project will use novel combination of numerical strategies. The proposed work will be performed in an interdisciplinary group environment that integrates research with undergraduate and graduate students through both courses and projects. The PIs will continue to actively recruit female and minority students through participation in prospective students? visits and recruiting talks.
Developing High Performance, Computationally Efficient Nonlinear Control Techniques For Polynomial Nonlinear Systems
Wu, Fen
06/01/2008 through 05/31/2011
National Science Foundation
Nonlinear control has been a very active research area in recent years, motivated by the fact that in many practical control problems, the controlled dynamics of the systems are dominated by nonlinear effects. Unfortunately, current nonlinear control techniques cannot satisfy stability and performance requirements simultaneously and often result in compromised designs. On the other hand, the availability of increasingly more powerful and less expensive microprocessors and the need for better performance have motivated control engineers to explore new nonlinear control algorithms for advanced applications. Nevertheless, significant progress in computational mathematics and convex optimization techniques in recent years has not been fully utilized in nonlinear control designs. Therefore, it is highly desirable to develop innovative control design methodologies and nonlinear control solution approaches to address these deficiencies. Intellectual Merit This proposal is aimed at developing a novel control approach to overcome limitations and computational complexity of existing nonlinear control techniques and applying it to a spacecraft control problem. By exploiting the polynomial nonlinear vector field, significantly improved control techniques could be obtained using non-quadratic Lyapunov functions and SOS programming techniques. The systematic control design approach is applicable to a larger class of nonlinear systems, and will solve challenging nonlinear robust control problem with optimized performance. The synergy among optimization techniques, control theory, and applications has the potential for substantial gains in all three areas and would greatly increase our ability to design, build and control the increasingly complex nonlinear systems. The proposed research could also help automate the control design process and verification of high performance nonlinear control laws, thus dramatically reducing the cost and the design circle of nonlinear control systems. We envision the proposed nonlinear control approach will not only provide effective design and computational tools for nonlinear systems, it will also lead to the invention of competitive nonlinear control theory. Broader Impact The application of proposed nonlinear control approach to the spacecraft control problem promises to enhance its maneuver capability and robustness properties, and improve spacecraft performance by optimizing its nonlinear control strategy. Through close collaboration with NASA Johnson Space Center, the research outcome will be disseminated to aerospace industry and the benefits of automated nonlinear control design techniques are expected to be widely appreciated. Because of its general nature, it is anticipated that the proposed research will have major impacts on other applications including aircraft, robot manipulators, automotive engines, and magnetic-levitated rotory machines, etc. Moreover, the developed on-line control course and virtual experiment testbed could provide a unique platform for learning, and enhance the educational program of North Carolina State University by attracting non-traditional students and providing students with hands-on experience. With the help of computer-aided nonlinear control design toolbox, this project could serve as a catalyst for the widespread use of high performance, nonlinear control techniques in engineering society.
Reconfigurable Robust Gain-Scheduled Control for Air-Breathing Hypersonic Vehicles
Wu, Fen
01/05/2007 through 01/04/2010
National Aeronautics & Space Administration
Hypersonic air-breathing vehicles offer a very attractive and potentially safer alternative to traditional rockets. However, Hypersonic vehicle flight presents significant challenges for control engineers including variable operating conditions, large modeling uncertainties and possible sensor/actuator failures. In this project, we will develop effective control approaches to address challenging control tasks during hypersonic flight. By synthesizing fault detection and identification (FDI), switching control, and gain-scheduling control techniques, we will develop reconfigurable control systems for enhanced fault-tolerant capability and design flexibility. Moreover, the study on probabilistic robust control will provide new perspective on robust control techniques. It will overcome the complexity of non-convex control problems and achieve practically acceptable engineering designs. The advantages of the proposed control approach for hypersonic flight will be demonstrated through high-fidelity nonlinear simulations. The success of the proposed research will realize the potential of hypersonic aircraft as launch vehicle and global transporter, thus has critical importance in achieving NASA's strategic goal. Throughout the project, the PIs will collaborate with researchers in NASA research centers for the verification of integrated control techniques and technology transfer.
Bio-Inspired Morphing Spacecraft
Yuan, Fuh
11/01/2008 through 09/30/2009
NCSU NC Space Grant Consortium (Prime--National Aeronautics & Space Administration)
The main objective is to utilize the latest materials technology to advance the performance of a small UAV for space exploration using known biologically-inspired methods. The BioFlight Senior Design Team of the North Carolina State University will to pursue this goal. In addition to this, further knowledge of the flight mechanisms used by birds will be sought as well. The ultimate goal of this year's project will be to produce a workable UAV that will utilize such phenomena as wing morphing to bring its overall performance to a level considerably above that of a conventional aircraft of similar size and configuration.
Acoustic Measurements for an Isotropic Plate (Task Order No. 6235-NC)
Yuan, Fuh
09/26/2008 through 09/25/2009
National Institute of Aerospace (Prime--National Aeronautics & Space Administration)
The purpose of this task (and the previous task order NNL07AD23) is to utilize the work done in determining the voltage response to an internal breakage in an isotropic plate to determine the nature and location of the breakage by matching measured and calculated responses. With the source of the calculated disturbance known, a matching measured response would point to a similar source type. This is the inverse problem to the determination of response from damage. It will enable real-time determination of damage on an aircraft from the monitoring of acoustic emission signals via an array of fuselage or wing mounted sensors and recording devices. It will also be a necessary intermediate building block to addressing the same problem for a composite structure in the future.
US-China Workshop on Smart Systems: Bio-inspired Materials, Mechanics, Control, and Sensor Innovation
Yuan, Fuh
09/01/2008 through 08/31/2009
National Science Foundation
It is proposed to conduct a joint U.S.-China workshop on the topic of Smart Systems: Bio-inspired Materials, Mechanics, Control, and Sensor Innovation at the Dalian University of Technology, Liaoning Province, China. The objectives of the workshop are: (a) to evaluate the current status of research and education in the topic areas in the United States and China; (b) to identify critical and strategic research and educational issues of mutual interest; (c) to identify possible joint projects and potential research teams for collaborative research activities; and (d) to identify existing research data, experimental test beds, and other resources that can be shared by those engaging in joint research projects. Bio-inspiration is stimulating the development of new innovative sensors, actuators, and control strategies that will comprise future smart structures and systems, expected to exhibit major gains in performance. The mechanics for achieving these gains, along with improved safety and reliability, are a current focus of aerospace, civil and mechanical engineers. Both the U.S. and China are working toward achieving these new developments, and research and education at universities in both countries are evolving accordingly. It seems clear, though, that certain synergies can be achieved when researchers and educators from the U.S. and China collaborate. Smart systems refer to the synergistic integration of sensors, actuators, physical structure and computing devices for decision making. Synergy may be considered in terms of dealing with complexity, performance, overall cost of integrated systems, physical dimension, time for development, ease of installation, and so on. Bio-inspired sensing and actuation will be essential toward the development of new materials, sensors, and actuators, spurring the design of smart controlled and health monitoring systems for aerospace and civil infrastructure. Such smart systems require a thorough understanding of their underlying mechanics and mechanisms in order to warrant their durability and performance. This is the motivation for organizing the U.S.-China joint workshop with multi-disciplinary representation from the aerospace, civil and mechanical engineering communities. The details of the proposed workshop activities and program schedule are provided in body of the proposal. Intellectual Merit: The intellectual merits of this workshop are embedded in the identification of high impact research issues of mutual interest to the U.S. and China in the area of smart systems focusing on bio-inspired materials, mechanics, control and sensor innovation, and in strengthening the U.S.- China network for conducting joint collaborative studies to address these research issues for the benefit of the research community and general public in the two countries. The collaborative research activities are expected to aid in the development of: (a) advanced bio-inspired materials for sensing and actuation; (b) innovative utilization of sensor systems and control approaches in smart systems; (c) aid the understanding of underlying mechanics and optimization issues through the utilization of smart systems; and (d) improve the effective diagnostic and prognostic evaluation of aerospace, mechanical and civil infrastructure systems. Broader Impacts: The workshop is designed to have a broad impact in the areas of smart systems in general, and bio-inspired materials, mechanics, control, and sensor innovation in particular, for aerospace, civil and mechanical systems through international collaborations both in terms of research and education. The workshop will invite, and make every effort to promote the participation of, young and underrepresented groups of researchers to enhance the diversity of representation and their involvement in international scientific activities. The workshop will also promote the international collaboration in order to leverage resources, as well as share technical data and research concepts for the mutual benefit of the two countries.
Integrated Diagnostic and Prognostic Airframe Structural Health Management
Yuan, Fuh
08/01/2008 through 07/31/2009
National Aeronautics & Space Administration
Integrated vehicular health management (IVHM) refers to a developing technology that continuously monitors the structural integrity of an airframe and provides information about the length of useful life remaining for the components that make up the airframe. The benefits to be realized through the addition of IVHM to aircraft design include improved safety, reduced cost of ownership, and lighter weight. The diagnostic capabilities of IVHM have been developed by to the point of being capable of producing relatively high resolution virtual images of any damage to structural components. The next steps in the development of the technology are the addition of Bayesian updating to dramatically improve the probability of detection and decrease the uncertainty associated with the life predictions. The prognostic capabilities also require development and verification through experimentation and comparison of results with those of current crack propagation software, such as NASGRO. A prototype IVHM system with diagnostic and prognostic capabilities should be completed by September, 2011.
Initiating Biologically-Inspired Morphing Flight Senior Design Project
Yuan, Fuh
07/01/2008 through 06/30/2009
NCSU NC Space Grant Consortium
The aim of this proposal is to seek support for setting up the experimental part of a senior design class, Biologically Inspired Morphing Flight. The experimental part will include smart materials, wireless sensors, and system hardware/software. With the help of these experiments the course would greatly benefit by integrating the various fields, complementing the scientific tools with hands-on experience, thereby allowing the students to get a complete picture of the subject. The ultimate goal will be to build an autonomous small morphing aircraft. The course demands creative integration of traditionally disparate disciplines such as aerodynamics; controls; structural topology and design approaches; smart materials and structures; signal processing; circuit design and control electronics; wireless sensors and communications; systems integration. An important component of the project is the wing sensing and actuation.
Integrated Probabilistic Diagnosis and Prognosis for Airframe Structural Health Management
Yuan, Fuh
01/01/2008 through 12/31/2010
University of Florida (Prime--National Aeronautics & Space Administration)
Continual on-line structural health monitoring/management (SHM) which is vital to IVHM is based on dynamic processes through early damage detection, determination of damage location and size (diagnosis) and then prognosis of damage propagation and remaining life. Each stage entails much uncertainty in the limited, uncertain nature of the sensor data, modeling, and material and geometric properties. In addition, a probabilistic approach can utilize most effectively the wealth of data provided by a SHM system. In effect it can become a flying fatigue laboratory that will continually narrow uncertainty in material parameters for a particular structure and hone the prognosis model. Based on the need and potential for a probabilistic framework, this proposal has two broad objectives. The first is to develop a probabilistic diagnosis and prognosis framework and demonstrate by simulations its benefits. The second objective, the goal of this proposal, is to develop an integrated diagnosis and prognosis tool and to demonstrate experimentally the application of the framework to airframe components. The two objectives will be implemented through a comprehensive research plan consisting of three primary tasks: (a) Develop/verify a computationally efficient Bayesian inversion model to accurately determine distributions of damage location and size based on piezo sensors/actuators and migration technique for damage diagnosis. (b) Develop Bayesian updating approach with data mining to improve accuracy and precision of diagnosis and prognosis. (c) Demonstrate experimentally the integrated damage diagnosis/prognosis for improving the fidelity of structure's health state and remaining-useful-life prediction. This integrated probabilistic diagnostic/prognostic framework conceptually could be extended to other SHM systems with multiple heterogeneous sensors. The results of the proposed research will pave the road towards improving safety of future air transportation systems, reducing component failures, replace preventive (scheduled) maintenance by predictive (on-demand) maintenance, and revolutionize vehicle maintenance and design.
Self-Contained Wireless Sensor Networks for Aerospace Structures Monitoring
Yuan, Fuh
05/15/2007 through 04/30/2010
National Science Foundation
The development of autonomous health monitoring framework based on smart sensors will require a major paradigm shift involving hardware/system software, smart materials, energy harvesting, on-board signal processing, SHM algorithms, and wireless communication. The proposal seeks to develop self-contained wireless sensors for actively interrogating the damage in monitoring aerospace structures. The proposed wireless sensor networks will be designed so that they do not need any batteries nor any wires for power delivery and data transmission. Therefore, the wireless sensors can be readily mounted on the structure in a noninvasive manner, in particular in the areas of limited accessibility. A Wireless Intelligent Sensor Platform (WISP) developed at NC State offers, at the first time, an environment for active sensing research and will be employed as a basis of this research. Special attention will be given to developing a Wireless Intelligent System (WIS) for active sensing allowing continuous monitoring of aerospace structures and near real-time damage localization. These low-cost self-powered sensors with self-diagnosis and self-calibration capabilities will allow localizing the damage at the local network, significantly reducing the amount of information wireless transmitted to the monitoring station for damage identification. The ultimate goal of this investigation is to provide flight crews or ground control center with a versatile and powerful tool to visualize the damage in chronic structural areas. The proposed work builds on a highly successful project in which the PI developed and tested the WISP for passive sensing and demonstrated analytically and experimentally the identification of different sizes and shapes of damage utilizing migration technique, which is widely used in geophysical exploration. The research plan consists of four major tasks. Namely: (a) Optimize, develop, and build an MsM energy harvesting subsystem; (b) Develop self-diagnosis and self-calibration capabilities in WIS; (c) Design and construct active/passive sensing subsystem and WIS; (d) Prototype and test the WIS in both laboratory and field environments.
Probability Based Integration of Structural Health Monitoring into the Aging Aircraft Sustainment Program
Yuan, Fuh
12/01/2006 through 11/30/2009
University of Florida (Prime--US Air Force-Office of Scientific Research (AFOSR))
Continual on-line structural health monitoring/management (SHM) holds the promise of revolutionizing aircraft maintenance and design by providing an accurate picture of structural damage that allow predictions of remaining useful life (RUL) without corrective maintenance. By allowing condition-based maintenance (CBM), SHM will reduce cost while extending the average life of the fleet, since it will identify the small percentage of high-risk aircraft that currently force conservative maintenance on all aircraft. SHM is based on two complementary processes of damage diagnosis and prognosis of remaining life, each entailing much uncertainty in the limited, uncertain nature of the sensor data, modeling and material and geometric properties. Therefore, a probabilistic framework is key to efficient design and implementation of SHM. Furthermore, with continual flow of information about damage and damage propagation extracted from raw sensor data, a probabilistic framework should allow an SHM system to progressively improve its accuracy, and progressively narrow the distribution of material properties and RUL for the structure, leading to ever more accurate prognosis. Based on the need and potential for a probabilistic framework, this proposal has two broad objectives. The first is to develop a framework and demonstrate by simulations the benefits the framework will impart to an SHM. The second objective is to demonstrate the application of the framework to a specific SHM system, focusing on the use of Bayesian updating for improving probability of detection (POD) models and prognosis accuracy. For this purpose we will focus on developing a Bayesian inversion framework for PODs using an array of piezo sensors/actuators with guided wave diagnosis. The two broad objectives will be implemented through a comprehensive research plan consisting of three primary tasks: (1) Develop a Bayesian inversion framework for accurately determining PODs based on a linear array of piezo sensors/actuators; (2) Develop Bayesian updating approach to improved prognosis (3) Demonstrate the integration of the statistical models of diagnosis and prognosis for improving the fidelity of RUL prediction given to commanders. The results of the proposed research will pave the road towards the implementation of CBM by replacing preventive (scheduled) maintenance by predictive (on-demand) maintenance.
Probing the Electromechanical Properties of Functional Nanowires Using a Microfabricated Device
Zhu, Yong
07/01/2008 through 06/30/2009
NCSU Faculty Research & Professional Development Fund
One-dimensional (1D) nanostructures including nanotubes, nanowires and nanobelts have been demonstrated in a large number of applications in nanoelectronics and nanophotonics with excellent performance. For instance, a variety of gas, chemical and biological sensors are built upon carbon nanotubes or silicon nanowires; a number of waveguides, light-emitting diodes, and photodetectors are based on semiconductor nanowires. However, the applications in nanoelectromechanical systems (NEMS) are relatively behind. This is likely due to the fact that electrical and optical properties of 1D nanostructures have been better understood than mechanical properties. It is in fact a grand challenge to characterize the mechanical properties of individual 1D nanostructures. In the limited number of NEMS devices, almost all of them to date are based on external actuation mechanisms such as electrostatic or magnetic actuation. Kim and Lieber [5] reported a carbon nanotube-based nanotweezer. The carbon nanotubes used as the tweezer's arms were operated by the electrostatic force. Very few devices make use of their electromechanical properties. Mainly due to the constraint of mechanical testing, it is difficult to measure such coupled properties too. Above all, it is of critical relevance to characterize the electromechanical properties of these functional nanowires. That requires us to overcome many challenges associated especially with mechanical testing. In this proposed research, a specific electromechanical property, piezoelectricity will be investigated with zinc oxide (ZnO) nanowires as an example.
Mechanical and Piezoelectric Characterization of ZnO Nanowires for Energy Harvesting Applications
Zhu, Yong and Ro, Paul
01/01/2009 through 06/30/2010
National Science Foundation
Nanodevices fabricated with one-dimensional nanostructures (such as nanowires and nanotubes) are excellent candidates for implantable medical devices, sensors and wireless electronics. However the reliance on external power source may present a limitation for these devices. Recently piezoelectric nanowires (such as ZnO) have been demonstrated for converting nanoscale mechanical energy (e.g., environmental vibration) into electric energy. This approach, though promising, is facing critical challenges, e.g., how to enhance the conversion efficiency. The efficiency of energy harvesting depends on the accurate characterization of the ZnO nanowire properties including the Young's modulus, piezoelectric constants and dielectric constants. Therefore, the objective of this proposal is to gain fundamental knowledge on the mechanical and piezoelectric properties of ZnO nanowires. These insights will be garnered through development of a novel dynamic testing system that measures nanostructure electromechanical properties at given environmental conditions. Intellectual Merit: A MEMS device will be developed to test the mechanical and piezoelectric properties of ZnO nanowires at various frequency ranges (quansi-static to dynamic) and various loading conditions (uniaxial tension and bending). Next, the same dynamic testing system will be adjusted to be an energy harvesting device that can convert elastic mechanical energy from the same nanowire with known properties subject to bending and longitudinal stresses into electrical energy. Finally, energy harvestin from multiple strands of ZnO nanowires under two types of loadings will be investigated. First, the elastic bending energy of the nanowires will be analyzed and tested for their average energy harvesting capability. Next, a similar set up will be designed for testing the nanowires undergoing the longitudinal strain. Clever yet simple parallel designs are proposed for ease of energy harvesting from multiple strands, which would not be possible under AFM tip-based approaches. Also, to simulate ambient vibrations of random nature (both amplitude and frequency), an ultrasonic actuator will be used to examine the limits of energy harvesting from these nanowires in more practical settings. Broader Impact: If successful, the proposed research will: (1) Enable a thorough understanding of the mechanical and piezoelectric properties of ZnO nanowires at various time scales and loading conditions of relevance to the environment. (2) Enable the design of energy harvesting devices whose energy conversion efficiency can be optimized for given environmental conditions. (3) Enable systematic characterization of electromechanical-coupled properties of other 1D nanostructures. (4) Lead to the involvement of underrepresented minorities in the nanoengineering research and education through local education and outreach activities. (5) Train future nano researchers in nanoscale property characterization and nanodevice design by the integration of the proposed research into the curriculum.
Microstructurally Engineered Armor System for Enhanced Survivability Through Optimum Energy and Momentum Dissipation
Zikry, Mohammed and Brenner, Donald
10/01/2006 through 09/30/2009
Army Research Office
As an alternative to the traditional trial-and-error approach to armor materials design, we propose here the integration of combinations of tailored brittle and ductile materials that would effectively optimize the fracture toughness of high strength materials that have been damaged due to blast and impact, in-situ over time scales commensurate with propagating wave and blast phenomena. Through development of physics-based material models at different length and time scales and integrating them with accelerated experimental strategies, we will identify the myriad of high strain-rate failure modes pertaining to heterogeneous systems subjected to blast and impact. Our proposed robust structural failure resistant designs will be based on mitigating damage and healing it by blunting simultaneous failure modes through increasing fracture toughness due to extreme changes in strain-rate, pressure, and temperature. This methodology will result in an optimized structural system that will be tolerant to blast and impact over a span of strain-rates, pressures, and temperatures
Predictive Microstructural Modeling of Failure Modes in High Strength Steels
Zikry, Mohammed
06/01/2008 through 05/31/2011
US Navy-Office Of Naval Research
A three dimensional thermo-mechanistic physically-based predictive framework is needed to understand interrelated effects such as grain orientation, rotation and morphology, interfacial thermal, stress and strain gradients, and GB distribution and orientation. The dominant failure mechanisms, which are pertinent to life-cycle operation that may occur on different length scales have to be identified and characterized.
Microstructural Modeling and Representation of Simultaneous Failure Modes in Crystalline Aggregates Subjected to Dynamic Loading Conditions
Zikry, Mohammed
09/01/2006 through 08/31/2009
US Army
Material failure in f.c.c. and b.c.c. systems can initiate and evolve simultaneously over different spatial and temporal scales. The reliability and life-service of systems subjected to extreme loading conditions have been severely hampered by the lack of understanding and validated predictive capabilities of how multiple failure modes, such as stress induced void initiation and coalescence, and intergranular and transgranular cracks can simultaneously initiate, interact, and evolve. How can material failure be accurately predicted and potentially controlled, mitigated, and prevented at the appropriate physical scale in systems subjected to severe changes in pressure, temperature, strain, and strain-rate? How do interfaces, such as grain-boundaries (GBs), sub-grain domains, and cell walls affect local behavior and how do these conditions scale to the meso- and macro- levels for realistic failure predictions? Can material interfaces, such as GBs, be designed for failure mitigation and energy dissipation at the system scale? The proposed methodology provides an integrated framework to simultaneously handle different interrelated physical mechanisms, such as a myriad of representative dislocation-density interactions with high and low angle GB interfaces, the growth and coalescence of a population of voids, and how these interactions can lead to either intergranular or transgranular failure. The formation of pile-ups at GB interfaces, as a function of dislocation-density partial and total blockage and absorption at GB interfaces, will be determined and related to behavior at the grain and aggregate levels. How pile-ups form, and whether stress fields accumulate or are relaxed by GB distributions and orientations, GB morphology, and local cohesive strengths, will be determined and related to void nucleation, growth, and coalescence. New three-dimensional dislocation-density based crystalline plasticity formulations will be used with grain-boundary (GB) kinematic interfacial schemes, void nucleation and growth formulations, specialized three-dimensional computational models, finite-element discontinuity functions, and in-situ experiments to predict how combinations of ductile failure modes initiate and evolve, at different physical scales, to complete rupture in f.c.c. and b.c.c. systems. These conditions will then be used with the proposed experiments to determine failure scenarios related to material rupture. Based on these predictions, optimal GB orientations and distributions can be determined to avoid and potentially control energy dissipation and failure in systems subjected to extreme changes in temperature, strain-rates, and pressures.
Center of Excellence in the Area of Human and Robotic Structures Technologies for Lunar and Planetary Exploration
DeJarnette, Fred; Nagel, Robert; Edwards, Jack; Yuan, Fuh; Noori, Mohammad Buckner, Gregory; Saxena, Vinod; Gopalarathnam, Ashok; Banks, Harvey and Chow, Mo-Yuen
10/01/2002 through 09/25/2012
National Institute of Aerospace
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