Crack Monitoring in the Welding Parts of Different Alloys of Aluminium using Digital Image Correlation

Abstract

Welding joints are directly or indirectly prone to different stress and strain damages. During the test performance of welding material the crack appears and these cracks continue to grow and then move from one surface region to another region. This load is continued to apply till the test fails. It is done to check the strength limit of the welded part. Also it is not easy to find the starting point where the cracks start to appear. There are various ways or techniques to find the cracks in the welded parts during the load tests. It includes ultrasound, thermography and use of strain gauges etc. In this dissertation work a procedure for finding cracks in the welded parts after performing certain strength tests utilizing digital image correlation (DIC) method is proposed. The main benefit of this method is that one can find the cracks of macroscopic category and also monitoring can be done during performing of tests. Here digital images are captured during the different load cycles. As load applied is more than the strength of material cracks start appear to visible. So it is possible to find and detect the location of crack on the welded part. Since the digital images are stored in the database so it becomes easier for verification and comparison. This test is performed only for the cracks present on the surface of the welded material.I.