Lamb Wave Damage Detection of Composite T-Joint Based on Cross Correlation Peak of Local Signal Envelope

The damage monitoring of composite T-joint in their service is very important to ensure the safety of aircraft structures. However, the load variations have significant effects on the Lamb wave-based damage detection of composite T-joint. In order to mitigate the load effect, a damage index method based on cross correlation peak of local signal envelope is developed, which measures the similarity of Lamb wave signals by the maximum cross correlation coefficient of the signal envelopes. The validity of the method is assessed by the synthetic signals and damage detection of composite T-joint under tensile load. The results show that the method can effectively mitigate the load effect on the Lamb wave-based damage detection, and detect the damage of composite T-joint under tensile load accurately.