Simplified modeling method of impact damage for numerical simulation of Lamb wave propagation in quasi-isotropic composite structures

In this paper, we present our investigation of impact damage modeling in a quasi-isotropic CFRP plate in which guided Lamb waves propagate. Because impact damages in CFRP structures consist of multiple microscopic damages, such as delamination, shear cracks, and transverse cracks, it is difficult to precisely model the impact damages for FEM analysis. However, in order to investigate the SHM systems to detect impact damages, we need to model various kinds of impact damages easily. Therefore, we attempt to establish a simple modeling method of impact damages. When the wavelength of a Lamb wave is much longer than the microscopic damages, we can assume the impact-damaged area as a homogeneous region with the stiffness degradation. The benefit of this model is to reduce the time to construct FEM models. In particular, we can easily set several damages in various positions of the structure.