Simplified Modeling of Impact Damage for Numerical Simulation of Lamb Wave Propagation in Composite Structures

Abstract

Impact damage is the most fatal damage that the carbon fiber reinforced plastic (CFRP) skin-stringer composite structure suffers from. In order to reliably detect impact damages with different size and location using structural health monitoring system, the configuration of the macro-fiber composite (MFC) transmitters and fiber Bragg grating (FBG) sensors should be optimized. In this research, authors attempted to model a homogeneous frustum-of-a-cone region with the reduction of quasi-isotropic stiffness matrix for FEM simulation of Lamb wave propagation. The decreasing rate of the stiffness matrix was determined based on the velocity change of ultrasonic waves and the cross-section observation of the impact-damaged area. Finally, the validness of this simplified modelling method was quantitatively confirmed through the comparison with the multiple delamination modelling.