Study on the acoustic fields characteristics radiated by ultrasonic phased array in multilayered anisotropic medium

Combining ray tracing technique based on minimal time principle and the Gaussian Beam Equivalent Point Source (GBEPS) model,a systematic method is given to calculate the acoustic fields from ultrasonic phased array in multilayered austenitic steel medium.In this method,the austenitic steel is assumed as a transverse isotropic medium.The acoustic fields from ultrasonic phased array mounted on a wedge,in an austenitic steel with grain orientation of 0 degree are calculated,and the results are in good agreement with that obtained by COMSOL.Using different time delay laws,beam steering and focusing in three layered austenitic steels with different grain orientations (0°,30° and 100°) are realized and the characteristics of fields are discussed.Simulation results show that different grain orientation generally results in different beam steering and beam focusing.Although the fields can be controlled to steer or focus at desired place through time delay laws,the width and amplitude of steered and focused fields will be still affected by the difference of grain orientation.