Propagation Characteristics of Lamb Waves in Anisotropic Composite Plates Under External Loading

Composite plates are inevitably subjected to external loads during service. Understanding the propagation characteristics of Lamb waves in anisotropic composite plates under such loads is critical for enhancing the reliability of structural health monitoring (SHM) systems. Based on the theories of finite deformation and weakly nonlinear elasticity, we derived an acoustoelastic theoretical model for Lamb waves propagating in prestressed anisotropic composite plates. Utilizing the Legendre orthogonal polynomial expansion method, we developed a solution algorithm to characterize Lamb wave propagation under external loads. To validate the accuracy of our method, we calculated the Lamb wave dispersion curves for the unloaded case and verified the results against the result of DISPERSE software. Leveraging the established model, we investigated the influence of load on Lamb wave dispersion curves and analyzed the effects of load magnitude on the propagation characteristics of fundamental Lamb wave modes across different frequencies. These findings provide valuable references for guided wave inspection of anisotropic composites, particularly in the presence of external loads.