Multi-Layered and Homogenized Models for In-Plane Guided Wave Excitation, Sensing, and Scattering in Anisotropic Laminated Composites

The numerical evaluation of elastic guided wave (EGW) phenomena is an important stage in the development and configuration of ultrasonic-based non-destructive testing/structural health monitoring (NDT/SHM) systems. To reduce the computational costs, which are typical for EGW simulations in laminated composite structures, and to make the corresponding parametric analysis possible, the latter could be treated by employing an effective single-layer model with homogenized anisotropic material properties. The present study investigates the applicability of such an approach to simulate EGW excitation, propagation, scattering, and sensing in laminate composite structures, which are among the typical problems for ultrasonic-based NDT/SHM. To this end, two homogenized models have been implemented: the well-known static long-wave homogenization approach and the advanced Lamb wave homogenization method, where the effect of angular and frequency dispersion of EGWs is taken into account. To illustrate their performance, in-plane elastic guided wave excitation and sensing with surface-mounted piezoelectric transducers as well as wave scattering by a T-shaped stringer in cross-ply symmetric anisotropic laminates are examined by employing a recently developed semi-analytical hybrid approach. The limits of the applicability of both homogenized models are demonstrated and discussed via the comparison with the multi-layered model. The general conclusion from the obtained results is that only a qualitative, although computationally efficient, description of the EGW phenomena in the considered composites can be achieved using single-layer models.