Elastic constants identification of woven fabric reinforced composites by using guided wave dispersion curves and genetic algorithm

Abstract Typically, material properties are estimated by destructive tests and used in computational models in the design and analysis of structures. This approach is well-established in relation to isotropic homogenous materials. However, if this approach is used for composite laminates, inaccuracies can arise that lead to vastly different stress distributions, strain rates, natural frequencies, and velocities of propagating elastic waves. In order to account for this problem, the alternative method is proposed, which utilise Lamb wave propagation phenomenon and optimisation technique. Propagating Lamb waves are highly sensitive to changes in material parameters and are often used for structural health monitoring of structures. In the proposed approach, the elastic constants, which are utilised to determine dispersion curves of Lamb waves, are optimised to achieve a good correlation between model predictions and experimental observations. The dispersion curves of Lamb waves were calculated by using the semi-analytical spectral element method. The resulting dispersion curves were compared with experimental measurements of full wavefield data conducted by scanning laser Doppler vibrometer and processed by 3D Fourier transform. Next, elastic constants were determined by using a genetic algorithm which resulted in a good correlation between numerical and experimental dispersion curves.