Observations on fatigue crack paths in the corners of cold-formed high-strength steel tubes

S. Heinilä, G. Marquis, T. Björk

    Research output: Contribution to journalArticleScientificpeer-review


    Fatigue crack propagation in cold-formed corners of high-strength structural steel plate-type structures has been investigated. Large- and small-scale test specimens having complex residual stress states and subject to multi-axial cyclic local stresses have been investigated using both laboratory tests and numerical simulations. The combinations of alternating bending stress, alternating shear stress and static mean stress producing complex multi-axial stress states have been found to influence the fatigue crack path behaviour. Straight, zig-zag and "S" shaped cracks were observed depending on the material strength, range of cyclic loading, residual stress field and multi-axiality of the local stresses. Numerical simulations of residual stresses and linear elastic fracture mechanics were used to help understand the alternate crack paths. Mode I cracks propagating into a static compressive stress field did not arrest, but, due to the multi-axial stresses, combinations of mixed mode I, II and III crack growth with distinct paths were observed. The crack paths depend on the type and range of cyclic loading, material properties and residual stress conditions of the specimens. (C) 2007 Elsevier Ltd. All rights reserved.

    Original languageEnglish
    Pages (from-to)833-844
    Number of pages12
    JournalEngineering Fracture Mechanics
    Issue number3-4
    Publication statusPublished - 2008
    MoE publication typeA1 Journal article-refereed
    EventInternational Conference on Crack Paths - Parma, Italy
    Duration: 1 Sep 20064 Sep 2006
    Conference number: 6


    • crack path
    • multi-axial fatigue
    • cold forming
    • residual stresses
    • GROWTH

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