Research on Optimized Algorithm of Phased Array Ultrasonic Detection for Wheel Rim Defects

摘要

The wheel rim is an important part of the locomotive operation which carries the weight of entire train. The conventional phased array inspection method for wheel rim is poor efficiency and has poor resolution for some special angle defects. Therefore, in this paper, a frequency domain synthetic aperture algorithm based on virtual source technology is proposed to solve problems mentioned above. First, the focus of phased array is focused as arc inside the wheel rim forming many virtual sources. Then, high-resolution lines are synthesized used the delay rule with the A-scan data. Finally, the B scan is drawn based on the phase shift migration method in cylindrical coordinates. Through simulation and experiment, the results could show that the optimization algorithm proposed in this paper makes full use of the beam deflection and focusing of the phased array which improves the quality of the image, improves the detection ability of the far field, and increases the detection resolution of special angles. The algorithm could efficiently reduce the time of the imaging taking the speed advantage of the frequency domain imaging.