Ultrasonic phased array inspection of L-shaped components based on dynamic aperture focusing

When L-shaped component is detected by ultrasonic phased array inspection technique based on total focusing method, wave propagation path in the specimen became more complex to increase the computational difficulty of propagation time due to the complicated geometries of component. To solve this problem, a dynamic aperture focusing method, adjusting focusing program according to actual samples dynamically, was proposed on the basis of the total focusing method using full matrix data. Then, the dynamic aperture focusing program was designed for the surface characteristics of L-shaped components. A calculation method of wave propagation time was posed up based on the Snell's principle. Finally, a couple of full matrix data was simulated using the finite-difference time domain method to validate the dynamic aperture focusing method. The inspection experiment was carried out to image the defect in customized L-shaped metal specimen, yielding experiment results that are in good quantitative agreement with the true values. The results show that it is feasible and effective for dynamic aperture focusing method to test the L-shaped components.