Thermal Protection Systems (TPS) can be subjected to impact damage during flight and/or during ground maintenance and/or repair. AFRL/RXLP is developing a reliable and robust on-board sensing/monitoring capability for next generation thermal protection systems to detect and assess impact damage. This study was focused on two classes of metallic thermal protection tiles to determine threshold for impact damage and develop sensing capability of the impacts. Sensors made of PVDF piezoelectric film were employed and tested to evaluate the detectability of impact signals and assess the onset or threshold of impact damage. Testing was performed over a range of impact energy levels, where the sensors were adhered to the back of the specimens. The PVDF signal levels were analyzed and compared to assess damage, where digital microscopy, visual inspection, and white light interferometry were used for damage verification. Based on the impact test results, an assessment of the impact damage thresholds for each type of metallic TPS system was made.

Date Published: 29 April 2008
PDF: 8 pages
Proc. SPIE 6935, Health Monitoring of Structural and Biological Systems 2008, 693503 (29 April 2008); doi: 10.1117/12.778071

Published in SPIE Proceedings Vol. 6935:
Health Monitoring of Structural and Biological Systems 2008
Tribikram Kundu, Editor(s)