Ultrasonic phased array on the inner surface of circular stage for detecting the circumferential flaw in a pipe

A nouveau ultrasonic phased array on the inner surface of a circular stage is designed and fabricated for detecting the circumferential flaws inside a pipe effectively. The radiated acoustic field generated by the phased array is calculated with the spatial impulse response method. The influence of the ultrasonic radiated field with different parameters of the focusing phased array is considered, simulated, and studied. In order to determine the phase delay of each element in the phased array, the incident position at the pipe surface of the acoustic beam emitted by each element is derived and calculated by using Snell's law. The imaging experiments of the circumferential flaws in the pipe have been conducted for testing its detection capability with the phased array. It shows a good performance on detecting circumferential flaws in the pipe by the ultrasonic phased array with shape of the circular stage. It is found that the new phased array is superior to the traditional 1-D concave phased array for detecting circumferential flaws in the pipe.