A study on measurement of internal defect of aluminum liner by using the Out-of-plane ESPI

Today, environmental issues became a matter of worldwide concern. In particular, the major cause of greenhouse gas and environmental pollution is the automobile industry. Research is taking place to on materials to reduce a vehicles weight. In this paper, the Out-of-plane ESPI method was used to measure the internal defect of low weight and high pressure vessels. ESPI measurement method has many advantages. One advantage is that it is not only non-destructive and a non-contacting form of measurement, but it also does real time and precise measurements. The Out-of-plane ESPI system is a measurement of the deformation of an object. Therefore, it is very difficult to measure internal defect length by the Out-of-plane ESPI system. In the case of when deformation is converted into strain it is possible to measure internal defect length, because strain indicates a stress concentration. Interpreted results of the FEM method and the results of the Out-of-plane ESPI were compared for quantitative values of internal defect in the pressure vessel.