Defect Detection and Identification of Point-Focusing Shear-Horizontal EMAT for Plate Inspection

In this work, the defect detection method of different shapes and sizes by point-focusing shear-horizontal guided wave EMAT with the use of Periodic Permanent Magnet (PPM) is investigated through Finite Element Method simulation. To identify the defect shape, the circumferential scatter diagrams are introduced. Results show that the size of the rectangular prism defect could be distinguished by analyzing the reflected wave intensity in the 90 ° direction and the transmitted wave intensity in 270 ° direction. For right circular cylinder defects, the transmitted wave in the 270 °, and the ranges of 200-240 ° and 300-340 ° decrease with the increase of defect radius. Moreover, reflected wave increases in the range of 60-120 ° with the radius. Specifically, the rectangular prism and cylindrical defects could be distinguished by the range of reflected wave angles.