SYMPOSIA PAPER Published: 01 January 1982
STP30097S

Influence of Residual Stress on the Predicted Fatigue Life of Weldments

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A model was developed that predicts the influence of residual stress and stress ratio on the total fatigue life of a weld. The total fatigue life of a weld was considered to be composed of both crack initiation and crack propagation. Weld toe residual stresses were considered to influence the crack initiation life but not the crack propagation life.

The crack initiation life was estimated using cumulative damage concepts. Actual weld material properties (weld metal and heat-affected zone) were considered in the initiation life estimation. Neuber's rule was used to determine the local cyclic stress-strain behavior at the weld toe, and the fatigue notch factor was evaluated by using Peterson's equation. Residual stresses were introduced into the analysis as a simulated pre-stressing of the weld. Cyclic relaxation of the mean stress established during the set-up cycle was modeled by a power function and allowed relaxation to be considered in the life estimates.

Fatigue tests of steel weldments and aluminum butt welds having tensile and compressive residual stresses were conducted to verify the analytically predicted total fatigue life predictions. Agreement between analytical predictions and experimental results was quite good.

Author Information

Lawrence, FV
University of Illinois at Urbana-Champaign
Burk, JD
Shell Development Company, Houston, Tex
Yung, J-Y
University of Illinois at Urbana-Champaign
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Details
Developed by Committee: E08
Pages: 33–43
DOI: 10.1520/STP30097S
ISBN-EB: 978-0-8031-4841-3
ISBN-13: 978-0-8031-0711-3