Finite element modelling of lamb waves propagation in 2D plates and thin sheets for damage detection

摘要

Structural health monitoring is an evolving technology applied to identify, locate and quantify severity of damages in structures before failure. Lamb waves have become a keen interest for inspection since they can be used to monitor a large area from one single location. The objective of this research is to simulate lamb wave response using finite element method and its application to crack detection and identification in thin metallic engineering structures. Two types of specimen i.e. two-dimensional aluminium plate and thin aluminium sheets are simulated using commercially available finite element package ABAQUS. Initially phase velocity and group velocity dispersion curve are plotted for aluminium material. Thereafter simulation of individual specimens with cracks and without cracks is performed. Simulation results were compared and validated with actual results and were found to be in reasonably good agreement. This is certainly done by employing group velocity and time of flight for the distance travelled between the monitoring point and crack position. Assessment of lamb waves sensitivity to various sizes and shapes of cracks like rectangular and circular are also investigated and its effect on the structure is discussed in detail.