Numerical Approach to Welding Process and its Integration in Assessment of Fatigue life of Component

Welding is one of the most convenient and extensively used manufacturing process across every industry and is recognized as a cost effective joining technique. The root cause of most of the fabricated structural failures lies in the uncertainties associated with the welding process. It is prone to generate high residual stresses due to non-volumetric changes during heating and cooling cycle. These residual stresses have a significant impact on fatigue life of component leading to poor quality joints. To alleviate these effects, designers and process engineers rely upon their experience and thumb rules but has its own limitations. This approach often leads to conservative designs and pre-mature failures. Recent advances in computational simulation techniques provide us opportunity to explore the complex phenomenon and generate deep insights.

The paper demonstrates the methodology to evaluate the residual stresses due to welding in virtual environment. These stresses were validated with experimental results from X-ray diffraction testing method. Mesh mapping technique is used to allow transfer of non-identical mesh & results in welding simulation to map over structural analysis model. The fatigue analysis was carried out considering the residual stresses due to welding along with operational loads. A comparative study on fatigue life of component, both with and without residual stresses, was performed. The damage factor computed in fatigue analysis noticeably manifested that, tensile residual stresses are more susceptible to failures and needs to be addressed during product development process.