Interaction of weld-guided waves with defects

This paper investigates the interaction of weld-guided waves with defects located in the material adjacent to the weld, with application interest to non-destructive evaluation. The idea came from an experimental observation on a large butt-welded plate which found that the weld can concentrate and guide the energy of a guided wave traveling along the direction of the weld. Modal studies have been carried out previously by the authors which confirmed the existence of such feature guided modes and discussed their properties. These feature guided waves may be reflected by some defects when they are located on the path of the propagation. This paper considers different types of defects, including cracks perpendicular or parallel to the weld and circular holes, all in the heat affected zone next to the weld. The results are obtained from both finite element simulations and experimental measurements, showing good agreement. The sensitivity of two candidate welded-guided modes to different defects is discussed and suitable choices of frequency to detect these defects are suggested.