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Engineering Failure Analysis 15 (2008) 863–874
ate/engfailanal
Residual stress analysis and fatigue of multi-pass
welded tubular structures
Z. Barsoum
Royal Institute of Technology, Department of Aeronautical and Vehicle Engineering, Teknikringen 8, 100 44 Stockholm, Sweden
Received 19 June 2007; accepted 17 November 2007
Available online 5 December 2007
Abstract
The purpose of this study is to investigate the residual stresses near the weld root and the weld toe for multi-pass welded
tube-to-plates. Two different tubular joint configurations were studied; a three-pass single-U weld groove for maximum
weld ration and a two-pass fillet (no groove) welded tube-to-plates for minimum weld ration. A 2D axi-symmet-
ric finite element model was developed to calculate the temperature distribution, HAZ, ration depth and the residual
stress distribution for the sequentially coupled thermo-mechanical analysis. The calculated residual stresses pared
with experimental results and showed qualitatively good agreement. Torsion fatigue tests were performed in order to study
crack propagation from the weld root, lower and upper weld toe in mode III. Some of the tube structures were loaded with
a static internal pressure in order to separate the root crack and initiate the crack growth in mode III. Another batch was
PWHT and fatigue tested, in order to study the influence of residual stresses.
Ó 2007 Elsevier Ltd. All rights reserved.
Keywords: Welding simulation; Residual stresses; Tubular joints; Fatigue; Fracture mechanics
1. Introduction
Residual stresses have a significant influence on the fatigue strength of welded structures, and it is well
known that high tensile residual stresses have a detrimental effect on fatigue life pressive residual
stresses could have a favorable effect on fatigue life. bination of welding residual stresses with oper-
ating stresses to which engineering structures ponents are subjected can promote failure