Research on TPS damage identification method after thermal vibration cycles

Thermal Protection Structure (TPS) plays an important role in reusable vehicles, ensuring the safety of internal structures and systems. Structural Health Monitoring (SHM) based on guided wave is a widely used method for structural damage diagnosis, where guided waves are analyzed to evaluate the structural state through wave excitation and reception by a sparse sensor array. However, the impact of thermal vibration cycles on structures can bring changes in the guided wave signals, leading to misjudgments in the monitoring results. In this study, thermal vibration cycle experiments are carried out to examine the impact of thermal vibration cycles on guided waves. The Multiscale Fuzzy Entropy (MFE) method is employed for feature extraction and Mahalanobis distance is used to detect outliers in the MFE. Experimental results on the TPS show that MFE effectively extracts damage-sensitive features, and Mahalanobis distance accurately distinguishes between healthy and damaged features.