Lamb wave tomography technique for crack damage detection

Abstract

Crack damage monitoring is one of the research hotspot in sstructural health monitoring (SHM) for plate and shell structures. The crack damage monitoring method is studied using reconstruction algorithm for the probabilistic inspection of damage algorithm (RAPID), which is based on correlation analysis. RAPID algorithm can overcome the shortcomings of the complex signal analysis affected by multimode Lamb wave modes. The improved RAPID algorithm is proposed to reconstruct the tomographic image of the crack damage by correcting the signal difference coefficient (SDC) of the sensing path at the crack direction based on the principle of the Lamb wave reflection and scattering at the crack damages. The direction information of the crack damage can be strengthened. Furthermore, the length of the crack can be evaluated by the SDC distribution map. The experiments are carried out to validate the improved method and the results show that the reconstructed tomographic images can express the crack damage well and can evaluate the direction and length of crack damages. It indicates that the proposed method is useful for crack damage quantitative evaluation and growth monitoring.