Investigation of influence of edge on the excitation of Lamb waves

Abstract

In applications of guided waves for non-destructives testing usually it is recommended to attach transducers not close to the edges, boundaries or joints of the object under investigation, because it influences the received signals and as a consequence complicates interpretation of the results. However, there are many objects access to which is limited and there is no other possibility then to perform inspection from the position close to the edge of the object. The objective of the work presented is to investigate the regularities of the excitation of guided waves from positions close to the boundaries of the object.
The regularities of excitation of guided waves in a rectangular steel plate using transducers attached near the edges were investigated. The differences between excitation at far and close distances from the boundaries were demonstrated using a finite element modelling. The experimental investigations using an 8 element transducer array have been carried out and the obtained data were compared with the modelling results.