Crack growth analysis of the rib-to-deck welded joints of orthotropic steel deck under cyclic loading with negative stress ratio
Received:November 07, 2016  Revised:December 28, 2016
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DOI:10.7511/jslx201706004
KeyWord:orthotropic steel bridge deck  rib-to-deck welded joint  fatigue crack growth  cyclic loading with negative stress ratio  compressive stress  reverse plastic zone at crack tip
     
AuthorInstitution
杜青 天津大学 力学系, 天津
石广玉 天津大学 力学系, 天津
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Abstract:
      A four-step approach is used to numerically analyze the fatigue crack growth of the surface cracks at the rib-to-deck welded joint of an orthotropic steel deck.Firstly,the transverse stress at the rib-to-deck welded joint is computed based on the fatigue stress analysis model of orthotropic steel deck.Secondly,the stress intensity factors along the surface crack tips at the joint are evaluated efficiently by using a three-dimensional local model of the joint and Schwartz-Neumann alternating method.Thirdly,the influence of the compressive stress under cyclic loading on the fatigue crack growth is studied by using a two-dimensional fracture mode and a plastic damage model.The last step is to calculate the fatigue crack growth rate of the surface cracks at the rib-to-deck welded joint by substituting the stress intensity factors given in the second step into the fatigue crack growth formulas obtained from the third step.The presented results of the fatigue crack growth rate demonstrate that the reverse plastic zone at the crack tip will accelerate the crack growth rate by more than 50% for the rib-to-deck welded joints of an orthotropic steel deck under the cyclic loading with negative stress ratio.