Analysis of Lamb wave propagation in cross-ply laminates modeled with homogenized properties of transverse cracked plies

Abstract

This work aims to obtain a quantitative estimate of stiffness reduction in cross-ply laminates due to transverse cracks in 90-degree plies. The received Lamb wave signal in the pitch-catch transmission mode is expressed in terms of stress wave factors (SWFs) employing certain functions of the power spectral density of the received wave. The stiffness reduction in the laminate is deduced by a correlation with the stress wave factors (SWFs). The use of SWFs for damage quantification has been investigated in a previous experimental study. In the current work, cross-ply laminates of different configurations are modeled in Abaqus. The stiffness degradation due to transverse cracks is represented by a homogenized reduction of transverse Young’s modulus (E2) and in-plane shear modulus (G23) in the 90-degree plies of the laminate. When a Lamb wave propagates through a region of reduced elastic properties, reductions in the amplitude and speed of the propagating wave are expected due to the effective stiffness loss in the direction of wave propagation. One of the measured factors, SWF1, is found to capture this loss and shows a linear correlation with the laminate stiffness reduction. It is indicated that a quantitative assessment of the Lamb wave propagation in composites with damage is possible with a statistical measure of the received signal.