A point source/point receiver method for ultrasonic testing

Much of the theory and practice of ultrasonic testing involves the use of the plane wave approximation and of transducers large enough to generate planar wavefronts. Motivated in part by the emergence of engineering materials for which conventional techniques become impractical, the research reported here addresses the use of spherical waves generated by appropriately small transducers. Numerical simulations using the dynamic Green´s function of a plate were undertaken for various locations on both sides of the plate. Experimental data were obtained using a 1 mm diameter conical piezoceramic transducer as the source and an optical interferometer as the receiver at corresponding locations on an aluminum plate 178 mm in diameter and 31 mm thick