The Focusing of the Ultrasonic Phased Array in the Case of Non-contact NDE Methods

Abstract

Ultrasonic phased arrays are currently very popular in medical diagnostics and are used more and more for non-destructive evaluation (NDE) of different materials. NDE methods using phased arrays are used to analyse material properties, to measure wall thickness, to detect hidden cracks and other defects affecting structural integrity. Ultrasonic phased arrays can be used for the detection of different types of defects at different depths. In many cases depth of the critical zone, where defects can appear, is known, so the signal of the phased array has to be focused at this depth. In some cases immersion methods are preferred. In this paper the algorithm for the calculation of the time delays of the phased array probe, when the beam has to be focused at the required focal depth in the test object, after passing through the water layer (in the case of the immersion testing), is presented. The time delays of the phased array probe where calculated using developed algorithm in MATLAB. The verification of the algorithm was performed using CIVA software – the focused ultrasonic fields at the given depth in the second media were calculated using the time delays, calculated using developed algorithm.

DOI: http://dx.doi.org/10.5755/j01.eee.20.3.3638