Ultrasonic imaging using a phased array probe with a buffer consisting of a bundle of circular cylinders

The authors have previously investigated defect imaging using a phased array probe with a buffer consisting of thin plates. Although the phased array probe with a stacked plate buffer works well in defect imaging, there remains the issue of spurious images due to trailing waves generating at the side walls of a plate, and large stacked plate buffers are required to avoid the trailing waves. To solve these issues, a buffer consisting of circular cylinders is introduced. Considering dispersion characteristics of longitudinal vibration mode of guided waves in a circular cylinder and dimensions of phased array probe, cylinder buffers were designed and fabricated. Using the buffer consisting of circular cylinders, defects were well visualized with two imaging algorithms, plane wave imaging and total focusing method.