Application of vibration loading method for non-destructive testing of polymer Material by Means of Laser Shear Interferometry

In this paper, shearography or speckle pattern shearing interferometry, which is one of the moders optical and non-contact methods in non-destructive testings (NDT) of materials, is investigated. To this purpose, the workpeace should be subjected to a kind of loading. Some of the conventional loading methods in are relative vacuum loading, thermal loading, and Acoustic Loading. In this paper, The Acoustic loading method has been developed to stimulate and identify the defects. Two methods of thermal loading and Acoustic loading were compared on polyethylene and Teflon pieces with Delamination created behind them, thereafter, The effect of the type of loading on the capability to identify defects, as well as the quality of scanning results, have been examined. The results show that thermal loading requires more time for testing and has relatively low quality. In conclusion, using the Acoustic method not only has accuracy and speed but also the quality of the results has improved significantly for the samples.