Scattering of high order guided wave modes around a through-thickness circular hole

Ultrasonic guided waves have the ability to propagate long distances with minimal attenuation, which makes them particularly interesting in structural health monitoring (SHM) applications. Using the baseline subtraction approach, the signal from a defect-free structure is compared with the actual monitoring signal to detect and locate defects. There are many scientific publications on low-frequency guided waves for SHM purposes, and the interaction between guided wave fundamental modes and defects is also well documented. There is however a very limited number of studies on high order modes. High-frequency guided waves may enable the detection of smaller cracks related to conventional low-frequency guided wave SHM. The main difficulty at high frequency is the existence of several modes with different velocities. This study investigates the scattering of high order guided wave modes around a through-thickness hole with a view to developing a highly sensitive SHM method. A 3D finite element model of a 305 m...