Studies on effects of elevated temperature for guided-wave structural health monitoring

摘要

Large thermal variations can cause significant changes in guided-wave (GW) propagation and transduction for structural health monitoring (SHM). This work focuses on GW SHM using surface-bonded piezoelectric wafer transducers in metallic plates for the temperature range encountered in internal spacecraft structures (20℃ to 150℃). First, studies done to determine a suitable bonding agent are documented. That was then used in controlled experiments to examine changes in GW propagation and transduction using PZT-5A piezoelectric wafers under quasi-statically varying temperature (also from 20℃ to 150℃). Modeling efforts to explain the experimentally observed increase in time-of-flight and change in sensor response amplitude with increasing temperature are detailed. Finally, these results are used in detection and location of mild and moderate damage using the pulse-echo GW testing approach within the temperature range.