Enhanced generation and reception of ultrasonic Rayleigh waves through in-phase superposition of waves: theory and experiment

Abstract

Ultrasonic Rayleigh waves have been widely used in nondestructive testing and evaluation as they are sensitive to surface anomalies and conditions of a solid body. The techniques for the generation and reception of Rayleigh waves are mainly based on empirical methods, but theoretical research on these processes can better benefit their practical applications. In this work, a specific theory using a numerical integration is proposed to model wave beam fields generated by the widely used transducers, and to explain the enhanced generation and reception of Rayleigh waves. The simulation results show that Rayleigh waves are enhanced and can be detected through in-phase superposition of waves which are generated by the real sound sources in the solid surface. The reception of Rayleigh waves is also considered, the properties of received waves are thoroughly studied and a reception method with a line source is proposed. Several experiments have been performed to verify the proposed theory, and some important properties or potential applications of corresponding or optimized transducers are discussed based on the theoretical and experimental results.