Modelling of Lamb waves for damage detection in metallic structures: Part I. Wave propagation

Lamb waves are the most widely used acousto-ultrasonic guided waves for damage detection. The method is generally complicated by the coexistence of at least two highly dispersive modes at any given frequency. Furthermore pure Lamb wave modes may generate a variety of other modes by interacting with defects and/or by crossing different boundaries. Knowledge and understanding of Lamb wave propagation is important for reliable damage detection. However, the theoretical analysis of guided wave scattering forms an extremely difficult problem. This paper reports an application of the local interaction simulation approach for wave propagation in metallic structures. The focus of the analysis is on damage detection applications. The study also involves wave propagation in a piezoceramic actuator/sensor diffusion bond model in which one of the piezoceramics generates the thickness mode vibration. The simulated results are validated experimentally. The results show the potential of the method for wave propagation analysis in damage detection applications.