Fatigue Assessment of Ultrasonic Impact Treated Weld Joint Based on Numerical Modeling
Abstract
Welding technology is one of the most widely used fabrication methods for joining structural components, because its low cost, structural strength and geometric flexibility. Welding is considered a highly complex metallurgical process that results in irregular geometries, material imperfections/flaws and residual stresses. High tensile residual stresses and stress concentrations have a detrimental impact on fatigue life of structures, and thus a topic of great concern in product design. Ultrasonic impact treatment (UIT) is considered as one of the most effective post welding treatment techniques to enhance the fatigue performance of welded structures. This study aimed at assessment of UIT effects on the fatigue improvement of weld joints of 304L stainless steel. In this study, 3-D finite element models for the butt-joint and fillet joint were built to simulate welding process and UIT process. Abaqus/Standard was used to investigate the formation of tensile residual stress at weld joints. Simulated residual stresses were obtained and predicted tensile residual stresses for the butt-joint showed good correlation with experimental data. Abaqus/Explicit was used to analyze the residual stress modification under UIT process. Fatigue life of weld joints was predicted based on fracture mechanics based crack growth approach using the Forman model. The residual stress and stress concentration modifications were considered in fatigue life predictions. Fatigue life predictions were determined under constant amplitude load with various R ratios. Significant fatigue life improvements could be seen under UIT condition.
Degree
M.S.
Advisors
Ince, Purdue University.
Subject Area
Engineering|Mechanical engineering
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