A combined marching and minimizing ray-tracing algorithm developed for ultrasonic array imaging of austenitic welds

In order to improve the performance of defect sizing and locating in the ultrasonic inspection of austenitic welds, it is important to predict ultrasonic propagation paths using ray-tracing algorithms considering the anisotropy and inhomogeneity of the weld. An effective ray-tracing algorithm is proposed in this paper, which predicts rays in a P2M mode (from a point to a target matrix). The algorithm combines the marching ray-tracing strategy and the minimizing ray-tracing strategy to improve the computing efficiency and accuracy. The performances of both two ray-tracing strategies were analyzed, based on which the parameters of the proposed algorithm were optimized. The propagation times of all the target points were acquired by the algorithm and applied for ultrasonic array imaging. Images generated using inspection experimental signals can prove that the proposed algorithm can achieve P2M ray-tracing efficiently and realize good imaging performance.