On the localization of the antisymmetric flexural edge waves for obtuse angles

It is well known that the existence of edge waves is directly related to the localization of the acoustic field in the wedge. In this paper, it is shown experimentally and numerically that, for wedge angles smaller than about 100° (this angle may vary from one material to an other), the edge modes are confined in the tip of the wedge and may be considered as localized. For higher wedge angles, the analysis of the results shows a delocalization of the guided waves, which induces a new repartition of the acoustical energy in the wedge and a decrease in the amplitude of the wedge wave. This observation is numerically verified via an analysis in the time domain. Experiments realized on obtuse wedges demonstrate that the first ASF mode may be detected for wedge angles up to about 110°.