Developing a Self-Powered, Wireless Damage Detection System for Structural Health Monitoring Applications

The research presented in this manuscript introduces an independent structural health monitoring (SHM) system capable of performing impedance-based testing and detecting shifts in resonant frequencies. This independent structural health monitoring system incorporates a low power wireless transmitter that sends a warning signal when damage is detected in a structure. Two damage detection techniques were implemented on the SHM system and successfully used for evaluating structural damage. The first impedance-based technique is used to detect a gouge introduced to a composite plate. The second technique is a modal parameter technique that analyzes shifts in natural frequency; this technique was used to detect structural changes in an aluminum cantilever beam. In additional to the above test structures, an aircraft rib provided by the United States Air Force was also tested. This test was performed using the HP 4192A impedance analyzer so that the advantage of high frequency impedance-based tested could be demonstrated. Insight is given into the power characteristics of SHM systems and the need to incorporate power harvesting into these SHM devices is addressed. Also, a comparison between digital signal processors and microprocessors is included in this document.