An inverse procedure for crack detection in anisotropic laminated plates using elastic waves

Abstract

This paper presents a computational inverse technique to detect the location and length of cracks in anisotropic laminated plates. The scattered elastic harmonic wave fields in the laminated plates with horizontal or vertical crack are calculated using the strip element method, whereby the anisotropic laminated plate is discretized into strip elements in the thickness direction. By applying the principle of virtual work, the governing differential equations of the wave propagation are derived for the field variables. These differential equations are solved analytically together with the vertical boundary conditions. The crack length and its location are then identified by minimizing an error function, which is defined as the difference between the scattered wave fields in plates with actual and searched parameters. A uniform micro-genetic algorithm is employed to search for the correct parameters that minimize the error function. Numerical examples are given to demonstrate the efficiency of the procedure in the detection of the location and the length of both horizontal and vertical cracks in composite laminates.