Numerical Simulation for Dispersion Characteristics of Lamb Wave Propagation in Composite Laminates with Anti-Symmetric Surface Excitation

Abstract

For the nondestructive testing based on ultrasonic Lamb waves, the center frequency of the excitation signal should be appropriately selected to excite the specific Lamb wave mode in composite laminates according to the dispersion curves. However, it is difficult to achieve the dispersion curves of Lamb waves in composite laminates by using analytical methods. In this paper, the three-dimensional finite element model with the anti-symmetric surface excitation is established to analyze the dispersion characteristics of Lamb wave propagation in a composite laminate. The fundamental anti-symmetric (A0) Lamb wave mode is excited in the composite laminate by applying a concentrated force load and an anti-symmetric concentrated force load. The characteristics of Lamb wave propagation in the composite laminate are studied. Moreover, the group velocities of the A0 Lamb wave mode propagating in the composite laminate are calculated under the excitation signals with twelve different center frequencies. The group velocity dispersion curve of the A0 Lamb wave mode obtained by the established model is consistent with that of the guided wave software GUIGUW, which demonstrates the effectiveness and feasibility of the three-dimensional finite element model on analyzing the dispersion characteristics of Lamb wave propagation in the composite laminate.