Generation and Detection of Guided Acoustic Waves for Ndt Using High Temperature Wedges

Ultrasonic wedges which can propagate one longitudinal L and two orthogonally polarized shear S waves are presented. In order to use this wedge to generate and received guided plate acoustic waves along a metal plate at high temperatures brass which has a slow L and S wave velocities was chosen. Mode conversion method was used to convert L to S waves in the wedge. The mode conversion efficiency is 90.8%. The wedge has been tested up to 150°C. The L and S waves in the wedge have been converted to symmetrical, antisymmetrical and shear horizontal plate acoustic waves in a stainless steel plate. Experimental measurements demonstrated that the guided acoustic waves, in particular, shear horizontal plate waves using high temperature wedges may be an excellent approach for non-destructive testing and structural health monitoring of metal structures.