Adaptation of Electro-mechanical Impedance Structural Health Monitoring for Use in Spacecraf

The continued expansion of human spaceflight is resulting in an ever increasing need to automatically monitor the structural health of spacecraft, which requires ever smaller and more capable instrumentation and analysis systems. In this thesis, the Canary Impedance Logger (Canary IL) system is developed to monitor structural health using the electro-mechanical impedance method while reducing system weight to 20 grams. This system combines a small inexpensive embedded processor with a single-point DFT based embedded impedance analysis chip and an SD card for data storage. The dynamic response of a plate was modeled and compared with measured values. An assortment of space-related samples were tested and compared to results from a bench-top impedance analyzer. Low frequency results, from 1kHz to 10kHz, were made useful through the application of AC and DC leakage removal techniques while high frequency results, from 10kHz to 100kHz, did not require leakage removal. The completed system compares favorably with bench-top impedance analyzers. The frequency error is less than 1% with the potential for improvement via an external clock, and the resulting data provided comparable or superior damage detection using the RMSD method. The Canary IL demonstrates the potential for electro-mechanical impedance based structural health monitoring systems to meet the stringent size and weight requirements of spacecraft, and will provide a platform for future research.