A parametric fracture mechanics study of welded joints with toe cracks and lack of penetration

Timo Nykänen, XY Li, T Bjork, G Marquis

Research output: Contribution to journalArticleScientificpeer-review


The existing design rules give quite general guidelines to the fatigue assessment of different types of welded joints. The goal of this investigation was to give designers some tools, which would allow more precise assessment of the effect of dimensional variations on the fatigue strength. Therefore the fatigue behaviour of 12 common types of welded joints has been studied parametrically. Two-dimensional (2D) finite element models of the joint were made and evaluated using plane strain linear elastic fracture mechanics (LEFM) calculations. The as-welded condition was assumed with the result that no crack initiation period was considered and stress ranges were fully effective. A maximum tangential stress criterion with the Paris' crack growth law was used to predict the growth rate and direction of root and toe cracks under mixed mode K-I-K-II conditions. The effects of weld size and joint dimension ratios on the fatigue strength were systematically studied. In addition to tensile loading, bending and combined tension/bending moment loading in both directions are examined for positive and negative mean stress. (c) 2004 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)1580-1609
Number of pages30
JournalEngineering Fracture Mechanics
Issue number10
Publication statusPublished - Jul 2005
MoE publication typeA1 Journal article-refereed


  • steels
  • fracture mechanics
  • fatigue crack growth
  • welded joints
  • fatigue strength

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