Comprehensive Structural Health Monitoring

Sponsor: Air Force Research Laboratory, Wright Patterson AFB

Under U.S. Air Force Phase I SBIR funding, AITHER is investigating the feasibility of detecting incipient damage in aircraft structures using a wavelet-based health monitoring algorithm. Based on research previously performed at the Department of Aerospace Engineering at the University of Maryland, this research is attempting to expand upon a damage detection technique that was originally developed for helicopter transmissions. This algorithm, termed Constrained Adaptive Lifting (CAL), is optimized for a single sensor reading on the outside of the gearbox. The improved methodology will consider a set of distributed sensors along the aircraft structure.

AITHER’s Phase I efforts are focused on three areas. First, the CAL damage detection algorithm has been updated and modified to consider two-dimensional displacement or strain versus data from a cantilevered beam or three dimensional displacement/time data from a plate-like structure. The improved methodology has been termed Continuous-Constrained Adaptive Lifting or C-CAL. Second, algorithm validation has been performed with the use of finite element models. Finally, experimental validation is being performed using aluminum cantilevered beam models. Data has been gathered from the cantilevered beam models using a scanning laser vibrometer.

Future efforts would be directed towards gradually increasing the difficulty and realism of the experimental validation stages. Future updates include testing on plates and actual aircraft structures, composite structures, random excitations, and consideration of sensor strategies including distributed fiber optic sensors.