Guided wave based nondestructive testing and evaluation of effective elastic moduli of layered composite materials

The paper presents a nondestructive technique for the evaluation of elastic moduli of layered fiber-reinforced composites. It is based on the minimization of the discrepancy between the theoretically calculated and experimentally measured dispersion curves of guided Lamb waves generated by surface-mounted piezoelectric wafer active sensors. Numerical simulation is performed in the context of 3D linear elastodynamics for anisotropic solids. It relies on the explicit integral and asymptotic representations derived for the force-generated wave fields in terms of Green's matrix of the composite structure considered. The minimization of the least-square error sum between the measured and calculated data is achieved through a real coded micro-genetic algorithm. The reliability of the proposed approach is experimentally validated via static tensile tests as well as by the frequency response evaluation.