Detection of low-velocity impact damage in composite plates using lamb waves

A first approach to a rapid and cost-effective health monitoring system for composite structures is presented. Relatively small piezoceramic patches have been selected for the generation and reception of the fundamental anti-symmetric Lamb mode, A(0). The patches were distributed in a linear array in order for larger areas to be inspected. The propagation of Lamb waves was studied using Finite Element analysis and the optimal number and spacing of the transmitters was determined. Impact damage was successfully detected in multidirectional carbon fibre-reinforced plastic (CFRP) laminates using a very simple experimental set-up.