Durability of Surface Mounted PZT and FBG Guided Wave Sensors Under Reusable Launch Vehicle Representative Thermal Cycling

Abstract

This paper addresses the durability of cobonded PZT and FBG sensors for hybrid Guided Waves (GW) SHM systems under thermal cycles partially representative of a Reusable Launch Vehicle (RLV) use case. The cobonding process is tested as a potential alternative to the secondary bonding process for attachment of SHM sensor network onto composite structures. The evolution of the sensors with the thermal cycles is continuously monitored through measurement of the electromechanical impedance (EMI) spectrums (for PZT) and reflection spectrums (for FBG). Then the effects on the PZT sensors performances are investigated by measuring GW pitch-catch signals at different stages of the thermal cycles. As for FBG sensors, the thermal cycling is still ongoing and is expected to be completed by the time of the conference: additional results will be discussed then.