Residual stress measurement with non-destructive testing

• Main Author: Hariharan Ramasamy
• Other Authors: Brian Stephen Wong
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Materials::Testing of materials
• Online Access: http://hdl.handle.net/10356/63901
• Institution: Nanyang Technological University

Managing residual stress is a very important part of the production and maintenance process in many industries today. It is especially essential in industries that comply with high safety standards such as the aerospace industry. In the present work, measuring residual stress through non-destructive means had been examined. Currently the preferred method to measure residual stress is through X-ray diffraction. Alternative techniques such as ultrasound, which has been extensively used on steel, and eddy current, that has been used for flaw detection, were evaluated on common aerospace material Ti-6Al-4V. The test samples were shot peened to induce compressive surface residual stress. While the ultrasound results were disappointing in analysing compressive surface residual stress, eddy current testing shows a lot more potential in this area. The relationship between shot peening parameters, residual stress and surface texture was also looked into in the present work. Results from the X-ray diffraction proved that besides almen intensity, which is generally the only factor taken to consideration, variables like media size might have a greater influence on imparting residual stress and changing the texture of a surface.