A Comparison of the Capabilities of Portable Shearography and Portable Electronic Speckle Pattern Interferometry

摘要

Optical interference techniques such as electronic speckle pattern interferometry (ESPI) and Digital Shearography have been shown to be of great value for the Non-destructive Evaluation of composite materials. The recent signing of a contract to purchase numerous Airbus aircraft for commercial use in South Africa as well as the purchase of the Grippen military aircraft has resulted in the capabilities of optical interference techniques for NDE purposes receiving increased attention. The NDT Laboratory in the Department of Mechanical Engineering at the University of Cape Town has for a number of years been involved with the research, development, and applications of the optical NDE techniques of ESPI and Digital Shearography. This has led to the development of a portable inspection unit, based on Digital Shearography and the latest addition of a portable ESPI prototype. In order to compare the capabilities of the developed prototypes, industry acceptable test specimens of composite aircraft components are subjected to tests using both systems. The results are presented and comparisons are drawn highlighting the advantages and disadvantages of these two optical NDE techniques.