Static and ultrasonic structural health monitoring of full-size aerospace multi-function capsule using FBG strain arrays and PSFBG acoustic emission sensors

In this study, we developed an integrated static and ultrasonic structural health monitoring (SHM), that was achieved using fiber Bragg grating (FBG) arrays and phase-shifted FBG (PSFBG) sensors, to monitor a full-size aerospace multi-function capsule under varying load. The FBG and PSFBG were bonded using direct and remote adhesive methods, respectively, to ensure the performance of the integrated SHM. The static strain measured by FBG accurately followed the loading curve during the initial 15 min of the test, and subsequently exhibited an irregular trend due to damage. Acoustic emission signals induced by damage were first detected by PSFBG at 15 min 11 sec. Following the detectable irregular strain and AE signals, the failure of the capsule manifested as a wrinkling ultimately occurred at 18 min. The FBG arrays and PSFBG sensors performed well for the integrated SHM and demonstrated that the newly proposed method can alert the unhealthy status of a large-scale aerospace structure before catastrophic failure.