Authors:

Daniel Richard

Publication:

Materials Evaluation, Volume 76, Issue 3

Publication Date: 1 March 2018Testing Method:

Ultrasonic Testing

Over the last 15 years, phased array ultrasonic technology has dramatically changed the face of nondestructive testing. This advanced pulse-echo technique uses multiple elements in a transducer to precisely steer, focus, and scan an ultrasonic soundbeam. It is a reliable, repeatable, and efficient way to inspect complex geometries, visualize welded joints, and determine the size and type of flaws like surface and subsurface cracks in a range of materials. Phased array UT is especially effective in aerospace and aircraft applications where the use of carbon fiber reinforced polymer (CFRP) and other composite materials continues to expand. The multimaterial and anisotropic nature of CFRP is a challenge for nondestructive testing. Composite structures and components can involve large areas with varying geometries and thicknesses. Discontinuities, including porosities, delamination, and foreign bodies, can be introduced during the materials manufacturing process, and can occur in a particular layer of carbon fiber or in resin. Furthermore, suppliers of CFRP components face competitive pressures to meet the quality, cost, and delivery expectations of their customers. By and large, component manufacturers conduct ultrasonic testing in environments where an automated scanner can be used to control the alignment between the ultrasonic probe and the surface of the test material. Iterative time reversal is a real-time adaptive phased array UT technique that is designed to eliminate the effects of misalignment between the probe and the specimen. This article will explain how this adaptive UT inspection technique can improve inspection coverage and detection capability while maintaining test speed and efficiency.

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