Applications of Acoustic Surface Wave Visualization to Nondestructive Testing

Abstract

Acoustic surface waves offer many potential advantages as a tool in nondestructive testing. The concentration of the energy of these waves near the surface of a solid makes possible efficient interaction with subsurface defects which might otherwise be quite difficult to detect. Also the high propagation velocity of surface waves suggests that they may be used to achieve rapid inspection rates on large surface areas. This paper describes a simplified version of the visualization system of Adler, Korpel, and Desmares which has been used to investigate these applications. Photographs to be presented illustrate the deformation of the crests and troughs of surface waves which occur when they encounter thickness variations and holes in metal sheets and plates, cracks in surfaces, and metallurgical variations in nominally defect free material.