• Elastic Waves
  • Imaging Multiple Damages by Migration Technique
  • Wireless Sensor Networks
  • Diagnosis & Prognosis


Nanotube Sensor
Principal Investigator:
Granting Agency:
Introduction video
Real-time Intelligent Monitoring of reinforced Concrete Structures
Principal Investigator: F. G. Yuan (Co-PI: M. N. Noori)
Granting Agency: National Science Foundation
Abstract: This study is focused on the basic scientific and engineering challenges in the SHM of RC structures. The research plan includes: development of a robust and real-time pre-stack mitigation technique using ray theory for wave propagation modeling and scattering; laboratory measurements of physical models of RC structures; sensitivity of corrosion/de-bonding to selective diagnostic signals and to sensor placements, and development of signal processing and imaging visualization algorithms for unambiguous identification in location and sizing of the damages with high resolution. The objective is to develop a robust monitoring system to provide timely maintenance and safety assessment for civil structures.
Intelligent Health Monitoring of Aerospace Structures using Wireless Sensor Networks
Principal Investigator: F. G. Yuan
Granting Agency: National Science Foundation
Abstract: The work is targeted at developing an active distributed smart sensing system for quantifying and visualizing location and sizing of damage in aerospace structures in near real-time. The research emphasizes on three major tasks. Namely: (1) Develop smart sensors system and strain sensors for the MICA platform to facilitate monitoring of aerospace structures; (2) Develop and implement an multi-sensor fusion information system for on-board monitoring, damage detection, and damage localization in aerospace structures at local sensor level; (3) Develop a robust and near real-time ray-based migration technique at monitoring station for assessment and visualization of severity of the damage.
System Integration of Structural Health Monitoring in a UAV using Wireless Smart Sensor Technology
Principal Investigator: F. G. Yuan
Granting Agency: NASA Langley Research Center
Abstract: Successful use of smart sensors in structural health monitoring can change the philosophy of how structures are built. This project pursues the integration of a wireless sensor network onboard an unmanned aerial vehicle using piezoelectric sensors. The wireless data acquisition system will be streamed from the aircraft to a base station for collection. The data will be collected and stored onboard the aircraft for comparative analysis with the streamed data to determine the data integrity. This study examines new methods to achieve higher sampling rates, longer endurances through power scavenging techniques, and the development of intelligent sensors.
Atomistic Fracture Mechanisms in Crystalline Metals
Principal Investigator: F. G. Yuan
Granting Agency: NASA Langley Research Center
Abstract: The proposed research will study crack initiation and propagation using both atomistic and continuum elasticity methods, with emphasis on the linkage between continuum mechanics and the physics-based atomistic modeling of fracture. One of the aims is to test the validity and accuracy of continuum models by direct atomic simulations of fracture. For example, a pure mode-II crack based on linear elastic solutions has neither crack opening nor tractions along the crack surfaces. Such a configuration could not be comprehended from an atomistic point of view because atomic planes subject to pure shear slide past one another via propagation of dislocations.
Load Transfer and Fracture of Carbon Nanotubes
Principal Investigator: F. G. Yuan
Granting Agency: NASA Langley Research Center
Abstract: The proposed study will first focus on the tube-tube interactions regarding load transfer mechanisms. The study will include the usual van der Walls repulsion for aligned tubes where forces are transferred weakly in shear, and for different types or magnitudes of entanglement. The reduced elastic moduli will be simulated using molecular simulations and compared with the moduli using continuum model. The research will then focus on the failure path of bond rupture, leading to the fracture of the nanotubes. Simulation of strength by imposing a bond rupture criterion based on potential energy of bond will be investigated.
Multidisciplinary Modeling/Analysis
Principal Investigator: F. G. Yuan
Granting Agency: NASA Langley Research Center
Abstract: The objective of this work is to design, understand, and develop modeling for integration of multiple antennas on composite vehicle structure. Although the electromagnetic coupling of metallic vehicle structure with mounted antenna elements has significant effect on radio communication, and the effect of multifunctional composite material vehicle structure on radio communication need to be determined. The work deals with various types of composite material for vehicles that may affect the electromagnetic coupling of the antenna and vehicle. Numerical methods will be developed to determine the electromagnetic coupling between EM waves and composite materials.
Graduate Research in Aerospace
Principal Investigator: F. G. Yuan
Granting Agency: Boeing Company
Abstract: The work aims at developing an extension circuit board attached on the MICA smart sensor that can measure strain on the composite plate remotely.