Testing by Means of Transverse, Surface and Plate Waves

Abstract

When testing curved plates or pipes, transverse waves which are propagated along a zigzag path are frequently used (Fig. 15.1). Compared with longitudinal waves their chief advantage here is that if incident at angles greater than 33° in steel (30° in aluminium) they are totally reflected without being split. In such specimens they can therefore travel long distances provided the roughness of the surface is small compared with the wave length so that losses by scatter reflections do not occur. The effect of surface roughness, however, decreases as the angle of incidence becomes larger. In addition the amplitude decreases only according to the law of distance (divergence of beam) and the attenuation of the material for transverse waves.