Long Range Ultrasonic Guided Wave Focusing in Pipe Using a Phased-Array System

摘要

Guided wave focusing in pipe is discussed from three aspects: theoretical calculations, numerical FEM simulations, and experimental verifications. The guided wave focusing techniques are used to provide us with higher wave penetration power and defect circumferential resolution. An ultrasonic multi-channel phased-array system is employed to achieve guided wave focusing at a predetermined position in a pipe. When appropriate amplitudes and time-delays are applied to different channels of the phased array system, a constructive interference can be realized at the pre-determined focal spot. FEM simulations are performed to verify the theories and visualize the focusing phenomenon. The increase in penetration power is verified by experiments.