Optimization of Lamb Wave Methods for Damage Detection in Composite Materials

Cost-effective and reliable damage detection is critical for the utilization of composite materials. This paper presents part of an experimental and analytical survey of candidate methods for in-situ damage detection of composite materials. Results are presented for the optimization of Lamb wave techniques applied to quasi-isotropic graphite/epoxy specimens containing representative damage modes. Linear wave scans were performed on narrow laminated coupons and sandwich beams by monitoring the transmitted waves with piezoceramic sensors (PZT). Optimal actuator and sensor configurations were devised through experimentation, and various types of driving signals were explored. Lamb wave techniques have been proven to provide more information about the presence of damage and its severity than previously tested methods, and may prove suitable for structural health monitoring applications since they travel long distances and can be applied with conformable piezoelectric actuators and sensors that require little power.