Education

Research Description

Dr. Ngaile is interested in design and manufacturing, tribology in manufacturing, modeling and optimization of manufacturing processes, material characterization, and finite element analysis. Dr. Ngaile is developing new formulations of metal forming lubricants, and is studying how to tailor metal forming processes to minimize the quantity of toxic-rich lubricants needed in these processes. Also, he is studying the influence of ultrasonic vibration on microforming processes.

Publications

A novel hybrid heating method for mechanical testing of miniature specimens at elevated temperature

Li, L., Ngaile, G., & Hassan, T. (2017), Journal of Micro and Nano-Manufacturing, 5(2).

A novel hybrid heating method for elevated temperature mechanical testing of miniature specimens

Li, L., Ngaile, G., & Hassan, T. (2016), (Proceedings of the ASME 11th International Manufacturing Science and Engineering Conference, 2016, vol 1, ).

Analytical modeling of hydrodynamic lubrication in a multiple-reduction drawing die

Lowrie, J., & Ngaile, G. (2016), In 44th north american manufacturing research conference, namrc 44. (Procedia Manufacturing, 5) (pp. 707-723).

New punch design for the elimination of punch ejection load through manipulation of the elastic strain field in the punch nose

Lowrie, J., & Ngaile, G. (2016), Journal of Manufacturing Processes, 22, 49-59.

Preliminary investigation of the process capabilities of hydroforging

Alzahrani, B., & Ngaile, G. (2016), Materials, 9(1).

Novel extrusion punch design for improved lubrication and punch ejection

Lowrie, J., & Ngaile, G. (2015), (Proceedings of the ASME 10th International Manufacturing Science and Engineering Conference, 2015, vol 1, ).

Die-less hydroforming of multi-lobe tubular structures

Hummel, S., & Ngaile, G. (2015), Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture, 229(3), 435-452.

Enhancement of tribological performance via innovative tooling design for extrusion processes

Lowrie, J. B., Ngaile, G. (2014), (Proceedings of the ASME 9th International Manufacturing Science and Engineering Conference, 2014, vol 2, ).

Development of chemically produced hydrogen energy-based impact bonding process for dissimilar metals

Ngaile, G., Lohr, P., Lowrie, J., Modlin, R. (2014), Journal of Manufacturing Processes, 16(4), 518-526.

Optimal load path input in tube hydroforming machines

Ngaile, G., & Welch, G. (2012), Proceedings of the Institution of Mechanical Engineers. Part B, Journal of Engineering Manufacture, 226(B4), 694-707.

View all publications via NC State Libraries

Grants

Development of a Manufacturing Process for High-Power-Density Hollow Shafts

FIA (Forging Industry Association)(7/15/16 - 7/14/18)

×

Development of a Manufacturing Process for High-Power-Density Hollow Shafts

Sponsor: FIA (Forging Industry Association)

Start Date: 7/15/16

End Date: 7/14/18

Abstract

Lightweighting is being actively researched worldwide. The motivation to reduce the weight of a vehicle is largely driven by government regulations. For example, the fuel mileage requirement for cars in the US will increase to 35 mpg in 2020 [1]. For heavy duty trucks, the US is expected to cut carbon pollution by 17% from 2005 levels by 2020 [2]. The power train for cars and trucks carries a significant percentage of the total weight of a vehicle. For example, the power train in Classes 1–3 accounts for 36% of the total weight, whereas in Class 8 the power train accounts for 48%.The majority of power transmission systems used in the automotive, aerospace, maritime, and other industries employ solid shafts. Utilization of hollow shafts can drastically reduce weight, thus improving fuel efficiency. Although there are different ways that hollow shafts could be produced (e.g., machining), to meet the demand in the above-mentioned industries, any new manufacturing process must meet the following criteria: mass production potential, short cycle time, structural integrity, and cost effectiveness. We seek to devise a fabrication process that will combine (a) an innovative forming concept based on differential heating, (b) geometric optimization, and (c) multi-functional heat treatment.

Close

Optimization of DuraForce Fastening System via Numerical Modeling

DuraForce Fastener Systems, LLC (5/16/16 - 12/31/16)

×

Optimization of DuraForce Fastening System via Numerical Modeling

Sponsor: DuraForce Fastener Systems, LLC

Start Date: 5/16/16

End Date: 12/31/16

Abstract

One of the most concerning problems with a threaded fastener is the tendency to loosen over time, creating a joint failure. The main cause for bolt loosening is the side sliding of nut or bolt head relative to the joint. This movement causes relative motion between the threads of the nut and bolt. The self-loosening causes a reduction in the clamp force which results in joint slip. As a consequence of this, the bolt is subjected to bending loads and finally fails by fatigue. The main reasons of relative motion are: bending of parts that causes induction of forces at the friction surface, differential thermal effects cause by temperature or material difference, applied forces on the joint can lead to shifting of the joint surfaces leading to relative motion and hence loosening. To address this problem of self-loosening, Allied Industrial Corporation has developed a mechanism where the bottom part of a nut is made such that it has a conical shape that is used to transmit the force to a conically shaped collar. When the nut advances towards the collar, the annulus cone will deflect inward while the collar would deflect outward. In this way, both the annulus cone and the collar will store strain energy. Any tendency of bolt loosening can therefore be prevented by the stored energy. The goal of this study is to investigate the influence of various parameters (geometry, friction, materials) on the robustness of the new fastening system. The results are expected to provide Allied Industrial Corporation with design guidelines for the new bolt-nut fastening system. The investigation will be carried out with the aid of numerical simulations.

Close

ASME Code Application of the Compact Heat Exchanger for High Temperature Nuclear Service

US Dept. of Energy (DOE)(10/01/16 - 9/30/19)

×

ASME Code Application of the Compact Heat Exchanger for High Temperature Nuclear Service

Sponsor: US Dept. of Energy (DOE)

Start Date: 10/01/16

End Date: 9/30/19

Abstract

The proposed project will implement the recently developed elastic-perfectly plastic (EPP) analysis methodologies in accordance with the ASME Code, Section III, Division 5 for diffusion welded compact heat exchangers (CHXs) in high temperature nuclear service. Burst, and cyclic pressure and thermal experiments on diffusion bonded CHX specimens of SS316L and Alloy 617 will be performed for investigating stress concentrations at sharp channel corners and determining possible failure modes. Hybrid and printed circuit heat exchangers (H2X and PCHE) meet the requirements of space and weight savings, high thermal effectiveness, low pressure drop and high design pressure capability. These attributes improve cost and efficiency of advanced reactors and thereby advances DOE’s goal of carbon-free energy production. Currently, CHXs are covered by design rules in the ASME Code, Section VIII, Division 1 along with Section IX procedures for diffusion welding. But the Section VIII rules are limited to the maximum temperature of 427oC, hence cannot be applied to the intermediate and secondary heat exchangers (IHXs and SHXs) in Sodium Fast Reactors (SFRs) at 550oC and in high temperature gas-cooled reactors (HTGRs) at 950oC). No detailed design strategies for the CHX at the temperature range (550-950oC) have been published. For the IHXs in SFR and HTGR, thermal stresses, fatigue and creep deformation and rupture life limits must be considered for Section III, Division 5, Class A applications, and these are not covered in the Section VIII design methodology. Some IHX and SHX applications are anticipated to operate at significant pressure differentials in addition to cyclic thermal conditions. Hence, determination of thermal stresses in addition to primary stresses is essential for the calculation of creep strains, thermal deformations and peak stresses for fatigue and creep/fatigue usage estimates. It is anticipated that the thermal stresses in the diffusion bonded core will be large, especially during transients. Also high thermal strain concentrations are expected in the core near sidewalls, as well as at header attachment welds. On some scales, these concerns may be best addressed by the recently introduced EPP analysis methodology proposed for the evaluation of primary loads, strain limits and creep-fatigue in Division 5 of the ASME Code. Current Division 5 rules using simplified elastic, and decoupled creep and plasticity analyses have been deemed inappropriate for elevated temperature applications. Hence, EPP methodologies which considers creep-plasticity interactions will allow limit to various stress measures and strain limits. This project will perform a systematic set experiments on stainless 316L and Alloy 617 ASTM coupons and CHX specimens to develop structural design methodology based on EPP analysis in order to provide assessment of the elevated temperature failure modes of two types of CHXs under sustained and cyclic thermal and pressure loads. The research will be performed in consultation with the industry and ASME Code experts such that the outcomes can be used as technical basis for Section III, Division 5 ASME Code Case for CHXs in high temperature nuclear service.

Close

Novel Multi-Functional Hybrid Drawing Process (Area: Material Processes)

US Army - Army Research Office(6/20/16 - 2/19/17)

×

Novel Multi-Functional Hybrid Drawing Process (Area: Material Processes)

Sponsor: US Army - Army Research Office

Start Date: 6/20/16

End Date: 2/19/17

Abstract

Novel Multi-functional Hybrid Drawing Process The overarching goal of this proposal is to explore new multi-functional hybrid manufacturing processes, where several operations which are complementary to each other are carried out simultaneously. To gain fundamental knowledge pertaining to this new class of manufacturing processes we focus on a novel multi-functional hybrid drawing operation. The conceived system is comprised of multiple segmented dies with provision for high pressure fluid supply. The dies are conceived to generate hydrodynamic cavitation energy at the tool-workpiece interface which is instantly harnessed to carry out several operations aimed at enhancing metal drawing capabilities. Hydrodynamic cavitation can occur in a flowing fluid region where the pressure of the liquid falls below its vapor pressure. It is a result of gas bubble formation, growth, and finally bubble burst, resulting in energy release sufficient to plastically deform metallic materials. In this multi-functional drawing process, three manufacturing operations that would have otherwise been carried out independently can be realized: (1) real-time surface texturing via cavitating fluid which in turn generates lubricant pathways (micro pool lubrication), (2) real-time alteration of physicochemical properties of fluid (in-situ lubricant formulation) due to local adiabatic temperature rise during bubble implosion, (3) altering local and global state-of-stress thus increasing the shear stress τs, which in turn increases material formability, and (4) hydrodynamic “pseudo shot peening” via high velocity liquid micro-jets from cavitation, thus enhancing part surface integrity. The specific objectives of the study are (a) fundamental study of the mechanics of hydrodynamic cavitation and accompanied energy release that can be used to trigger other operations in real time, (b) study of real-time texturing of a blank/workpiece via hydrodynamic cavitation in a manufacturing process, where the produced micro-texture is instantaneously used to transport lubricant, thus enhancing tribological performance, (c) parametric study of the major variables that influence hydrodynamic cavitation, with focus on geometries that induce cavitation, physicochemical properties of fluid, fluid pressure gradient responsible for initiation of cavitation, vapor bubble size and bubble growth, (d) study of the potential of hydrodynamic cavitation in enhancing surface properties through imploding gas bubbles on the surface of manufactured products, and (d) explore the potential of altering the chemical characteristics of cavitating fluid, with a goal of increasing its lubricity; In situ lubricant formulation and the potential for producing nano-lubricants using shear energy emanating from high velocity micro jets.

Close

Study on Weight Reduction of Forged Parts Used in Heavy-Duty Truck Vehicles via Innovative Forging Techniques and Material Substitution

Forging Industry Educational and Research Foundation (FIERF)(10/12/15 - 12/31/16)

×

Study on Weight Reduction of Forged Parts Used in Heavy-Duty Truck Vehicles via Innovative Forging Techniques and Material Substitution

Sponsor: Forging Industry Educational and Research Foundation (FIERF)

Start Date: 10/12/15

End Date: 12/31/16

Abstract

The major goal of this study is to investigate the potential of innovative forging technologies, materials substitution, and part/design modifications to reduce weight in forged parts used in light- and heavy-duty truck vehicles, without diminishing the structural integrity of any component. This study will focus on vehicles falling in Classes 1, 2, 7, and 8, which consume 93% of the total fuel used in trucks in the US [1]. Classes 1 and 2 belong to the light-duty vehicle category, weighing less than 10,000 lb. Classes 7 and 8 represent heavy-duty vehicles, weighing over 26,000 lb [2]. The specific objectives are to (a) conduct a study on forged components used in power train, chassis, and suspension systems, and thereby identify families of parts with high potential for weight reduction through innovative forging technologies or material substitution, (b) evaluate the feasibility and economic practicability of forging components that are currently produced by casting or other manufacturing techniques, (c) carry out preliminary investigation on effective forging technologies that could be used in lightweight manufacturing. This might include hybrid forging/forming operations, and (d) carry out preliminary investigation on the energy flow path/maps that forged parts are subjected to during service life. Systematically assess from mechanical and metallurgical point of view, the potential for weight reduction in specific components.

Close

Study on Weight Reduction of Forged Parts Used in Light-and Heavy-Duty Truck Vehicles via Innovative Forging Techniques and Material Substitution

Forging Industry Educational and Research Foundation (FIERF)(11/30/-1 - 12/31/16)

×

Study on Weight Reduction of Forged Parts Used in Light-and Heavy-Duty Truck Vehicles via Innovative Forging Techniques and Material Substitution

Sponsor: Forging Industry Educational and Research Foundation (FIERF)

Start Date: 11/30/-1

End Date: 12/31/16

Abstract

The major goal of this study is to investigate the potential of innovative forging technologies, materials substitution, and part/design modifications to reduce weight in forged parts used in light- and heavy-duty truck vehicles, without diminishing the structural integrity of any component. This study will focus on vehicles falling in Classes 1, 2, 7, and 8, which consume 93% of the total fuel used in trucks in the US [1]. Classes 1 and 2 belong to the light-duty vehicle category, weighing less than 10,000 lb. Classes 7 and 8 represent heavy-duty vehicles, weighing over 26,000 lb [2]. The specific objectives are to (a) conduct a study on forged components used in power train, chassis, and suspension systems, and thereby identify families of parts with high potential for weight reduction through innovative forging technologies or material substitution, (b) evaluate the feasibility and economic practicability of forging components that are currently produced by casting or other manufacturing techniques, (c) carry out preliminary investigation on effective forging technologies that could be used in lightweight manufacturing. This might include hybrid forging/forming operations, and (d) carry out preliminary investigation on the energy flow path/maps that forged parts are subjected to during service life. Systematically assess from mechanical and metallurgical point of view, the potential for weight reduction in specific components.

Close

Reactive Supersonic Diesel Jets Under Extreme High Injection Pressure

National Science Foundation (NSF)(8/01/14 - 1/31/16)

×

Reactive Supersonic Diesel Jets Under Extreme High Injection Pressure

Sponsor: National Science Foundation (NSF)

Start Date: 8/01/14

End Date: 1/31/16

Abstract

High-speed (supersonic) liquid jets have wide applications in engineering for propulsion and power generation. The underlying hypothesis for this proposal is that under supersonic conditions shock waves are induced around liquid jets leading to significant enhancement in the atomization, mixing, ignition, and combustion. We propose to study a transient supersonic diesel jet under injection pressures of up to 1,000 MPa. The goals are to exploit the induced shock waves during liquid penetration, identify their effects on atomization, mixing, and combustion, and determine the effectiveness of extreme high injection pressures in mixing and combustion enhancement. Specifically, in this proposal, we will: a) study the liquid penetration, breakup, and interaction with the induced shock waves; b) study the influence of shock waves on the liquid atomization and the mixing with ambient air; c) study the influence of shock waves on ignition and combustion development; and d) gather fundamental knowledge pertaining to supersonic liquid jet with controllable dispensing pressures up to 1,000 MPa that can be disseminated to designers and developers of highly efficient, high power density, and clean next-generation internal combustion engines. Successful application of this phenomenon in internal combustion engines will lead to breakthroughs in engine design, allowing significant reductions in fuel consumption, thereby diminishing our dependence on foreign oil and reducing pollutant emissions.

Close

Increasing Participation of U.S. Students to the 9th International Conference on Micro-Manufacturing (ICOMM 2014); Singapore, 25-28 March 2014

National Science Foundation (NSF)(10/01/13 - 6/30/16)

×

Increasing Participation of U.S. Students to the 9th International Conference on Micro-Manufacturing (ICOMM 2014); Singapore, 25-28 March 2014

Sponsor: National Science Foundation (NSF)

Start Date: 10/01/13

End Date: 6/30/16

Abstract

The proposal seeks funding to provide partial support for 16 selected students studying in U.S. institutions to participate in the 9th International Conference on Micromanufacturing that will be held in Singapore March 25-28, 2014. It is important to train our next generation of engineers and researchers with a global perspective. The financial support through ICOMM 2014 conference will provide the student participants with opportunities to exchange ideas with leading researchers and engineers from worldwide industrial and governmental facilities, as well as the opportunity to visit companies involved with micromanufacturing in Singapore. In addition to nurturing a global micro-manufacturing vision, participants will learn the latest research areas and results in the fields of micro-manufacturing. Each recipient must be author or co-author of a paper that is accepted for the conference. A short statement on student?s vision on micromanufacturing will be requested along with a CV as part of the selection criteria. The requested NSF funds will provide a partial support to cover about 50-70% of total cost with the understanding that they will be responsible for the remaining 30-50%. The total cost includes travel, registration, and lodging.

Close

Parametric Study of a New Fastening System Via Numerical Analysis

Allied Industrial Corp.(5/15/13 - 12/31/13)

×

Parametric Study of a New Fastening System Via Numerical Analysis

Sponsor: Allied Industrial Corp.

Start Date: 5/15/13

End Date: 12/31/13

Abstract

Investigation of New Bolt-Nut Fastening System via Numerical Analysis It is commonly observed that nuts and bolts when used on vibrating structure are subjected to a phenomenon called ?vibrational loosening?. The main cause for this is the side sliding of nut or bolt head relative to the joint. This movement causes relative motion between the threads of the nut and bolt. The self-loosening causes a reduction in the clamp force which results in joint slip. As a consequence of this, the bolt is subjected to bending loads and finally fails by fatigue. The main reasons of relative motion are: bending of parts that causes induction of forces at the friction surface, differential thermal effects cause by temperature or material difference, applied forces on the joint can lead to shifting of the joint surfaces leading to relative motion and hence loosening. To address this problem of self-loosening, Allied Industrial Corp oration has proposed a mechanism where the bottom part of a nut is made such that it has a conical shape that is used to transmit the force to a conically shaped collar. When the nut advances towards the collar, the annulus will deflect inward while the collar would deflect outward. In this way, both the annulus and the collar will store strain energy in them. Any tendency of bolt loosening can therefore be prevented by the stored energy. The objective of this study is to investigate the influence of various parameters (geometric, friction, materials) on the robustness of the new fastening system. The results are expected to provide Allied Industrial Corporation with design guidelines for the new bolt-nut fastening system. The investigation will be carried out with the aid of numerical simulations.

Close

MRI: Development of a Miniature, High Temperature, Multiaxial Testing System for Advanced Materials and Engineering Research

National Science Foundation (NSF)(8/15/13 - 7/31/17)

×

MRI: Development of a Miniature, High Temperature, Multiaxial Testing System for Advanced Materials and Engineering Research

Sponsor: National Science Foundation (NSF)

Start Date: 8/15/13

End Date: 7/31/17

Abstract

A novel testing system will be designed and developed for mechanical testing of miniature tubular specimens under any combination of axial, torsional, and internal pressure monotonic and cyclic loading in the room to 1000oC temperature. The proposed test system size and orientation will be designed such that it can be set under an optical microscope (OM) and scanning electron microscope (SEM) for in-situ microstructural studies. With the emerging research in materials genome and integrated computational materials engineering, importance and significance in performing materials testing under realistic multiaxial loading and environmental (temperature, chemical and gas) conditions are in urgent need. For enhancing resilience of manufactured components, design of new materials should consider failure mechanisms at critical points (weld toe, stress concentration and hot spot) through testing miniature specimen under multiaxial loading. Such tests need to be performed at high temperatures for understanding premature failures of components in energy and aerospace industries. Manufacturing processes, welding, cold drawing, quenching, surface finishing etc. induce localized material heterogeneity whose influence on failure mechanism can only be studied through testing miniature coupons. Extreme service loading and environmental conditions alter local material properties, which can only be studied through miniature specimens in determining remaining life of critical components. Development of micro-fabrication techniques requires material properties and their evolutions which can only be determined accurately through miniature specimen testing under realistic loading. According to the investigators? knowledge, the proposed testing system currently is not commercially available anywhere in the world. Moreover, even a standard size axial-torsion mechanical testing machine with or without high temperature capability is not available at any universities in North Carolina or its neighboring states. The proposed miniature testing system will be shared by a large group of inter and intra university researchers in performing fundamental research on advanced material design and characterization, micro-forming, constitutive modeling, computational modeling, and failure-life prediction for the energy, aerospace, automobile, electronics, communication, biomedical, sensor and infrastructure industries. The proposed testing system will create research opportunities in material design and component manufacturing, integrated through constitutive and computational modeling research, as well as, meeting the research needs of material characterization usually obtained through standard testing systems. Development of the proposed testing system will performed by detailed thermo-mechanical analysis. Technologies of actuators, sensors, heating and pressurization, digital image correlation, water cooled grips and their controls will be critically evaluated in developing and integrating technologies needed for developing the proposed material testing system. Cooperation with the U.S. commercial partners will facilitate this process. The proposed system will impact design and development of new materials, high performance components, and micro-forming processes. Other important outcomes will be eliminating the long (10-20 years) trial & error methods of designing new materials for enhancing component life, and predicting failure life of components with much less uncertainty than today. Two Graduate and one undergraduate student will be trained on the novel testing system through designing and developing the proposed testing system. Many other students will be trained for use of the testing system in performing their research towards MS and PhD degrees. Undergraduate students through their research projects and K-12 teachers through The Engineering Place and Women in Engineering will perform experiments with the proposed system. Partnership with an US commercial testing system manufacturer will allow quick commercialization of the new system to other r

Close