Fatigue analysis of non-load-carrying fillet welded cruciform joints

Timo Nykänen*, G. Marquis, T. Bjork

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review


The goal of this investigation was to study the effect of local geometrical variations of the weld on the fatigue strength. Therefore the fatigue behaviour of non-load-carrying cruciform fillet welded joint under tensile loading has been studied parametrically. Several two-dimensional (2D) finite element models of the joint were analysed using plane strain linear elastic fracture mechanics (LEFM) calculations in order to get the magnification function M-k. A maximum tangential stress criterion was used to predict the crack growth direction under mixed mode K-I-K-II conditions. The derived M-k solution was then applied both for continuous weld toe cracks and also for semi-elliptical toe cracks at the deepest point of the crack front. An experimental crack aspect ratio development curve was used for propagating semi-elliptical cracks. The as-welded condition was assumed with the result that no crack initiation period was considered and stress ranges were fully effective. The Paris crack growth law was used to predict the growth rate. The effects of weld toe radius, flank angle and weld size on the fatigue strength were systematically studied. Finally, predicted fatigue strength values corresponding to different assumed crack sizes were compared with the available test results. (c) 2006 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)399-415
Number of pages17
JournalEngineering Fracture Mechanics
Issue number3
Publication statusPublished - Feb 2007
MoE publication typeA1 Journal article-refereed


  • fracture mechanics
  • fatigue
  • welded joints
  • magnification factor
  • fatigue strength
  • initial crack size


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