Numerical and experimental investigation of defect detection in polymer materials by means of digital shearography with thermal loading

Abstract

Laser shearography is a relatively new and useful method for nondestructive testing of many kinds of material that need robust methods to be applicable in industrial environments. To get the best results of this inspection method, adjusting the loading parameters properly and precisely is of a great consideration. In this article, a new numerical–experimental procedure to study the effects of thermal loading parameters in the shearography test of defected materials is presented. In this regard, a numerical procedure was developed to simulate shearographic fringe patterns using finite element analysis and supplementary programming. The modeling method was evaluated using experimental tests in a Plexiglas circle subjected to the thermal and mechanical loadings. Flat-bottom holes indicating internal defects of the test part were simulated and experimented to study the parameters that should be adjusted and controlled to get desirable outcomes from shearography nondestructive testing. It has been showed that for each distinct case of nondestructive testing, a thermal loading diagram can be extracted to get credible results.