Ultrasonic field analysis with local interface curvature effect based on the multi-Gaussian beam model

In ultrasonic testing, the amplitude of echoes is determined by the sound pressure along the acoustic axis. When the workpiece has a local curved surface, the ultrasonic field redistribution has a close relationship with the curvature of the incident local region, which raises questions of testing validity and accuracy. In order to develop the curvature adaptation window for a given test condition, the influence of local curved interface on the ultrasonic transmission and reflection field is analyzed quantitatively in this paper. Based on the multi-Gaussian beam model, the distribution of transmitted and reflected sound pressure in the local curved region is calculated by using matrix transformation technique. Furthermore, the relationship between interface curvature and sound pressure along the acoustic axis is obtained. To validate the accuracy of proposed calculation model, developed relationship has been compared against a finite element method computed using COMSOL Multiphysics. It is indicated that the proposed calculation model is more efficient and the regular changes of sound pressure are basically consistent with that of finite element method.