Non-destructive measurements of thickness and elastic constants of plate structures based on Lamb waves and particle swarm optimization

Abstract

Lamb wave has become an important non-destructive measurement method due to its advantages of small attenuation, easy excitation, and simultaneous inversion of multiple parameters. According to its propagation properties, we proposed an improved particle swarm optimization method for the inversion of the thickness and elastic constants of plates in the study. Numerical simulations and validation experiments further confirmed that the Young's modulus, Poisson’s ratio, and thickness of plates could be accurately obtained from the measured zero-order modal Lamb wave dispersion curves. Then, through a series of orthogonal experiments, the influences of the error sources of measurement points on inversion parameters were explored. In addition, the statistical significance of the above influences on each inversion parameter is discussed in detail. This study provides a basis for the accurate and efficient non-destructive measurements based on Lamb waves.