Numerical investigation of innovative nonlinear ultrasonic spectroscopy for detection and sizing interface defects in composites

Abstract

The article is devoted to innovative nonlinear acoustic techniques of non-destructive testing (NDT) of composites. Modern composites have a very complex inhomogeneous structure with a large number of interface bond-lines. Along these bond-lines there are interface defects, such as delaminations, microcracks, debonding and weakening of adhesive bonds. This leads to the necessity of distinguishing from each other a signal from given defects and a signal from interface bond-lines. The task becomes more complicated because interface defects have a very small thickness of micro or even nanoscopic scale. Conventional techniques of ultrasonic testing have a very low sensitivity of these defects detection. The article describes a novel acoustic-mechanical approach to numerical modeling of nonlinear acoustic interaction of ultrasonic wave with interface defect. The results of computer simulation of this nonlinear acoustic interaction are analyzed. A simple technique of nonlinear ultrasonic spectroscopy is suggested for detecting and sizing the interface defects.

http://dx.doi.org/10.5755/j01.u.66.2.528