Numerical simulations of fatigue crack initiation and propagation based on re-tensile plastic zone generating load criterion for in-plane gusset welded joints
Numerical simulations of fatigue crack initiation and propagation based on re-tensile plastic zone generating load criterion for in-plane gusset welded joints
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DOI：
10.1007/s00773-009-0044-7
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发表时间：
2009-02
影响因子：
2.6
通讯作者：
Y. Nagata;K. Gotoh;M. Toyosada
中科院分区：
文献类型：
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作者：
Y. Nagata;K. Gotoh;M. Toyosada
焊接组合钢结构的疲劳破坏是造成事故的主要原因，因此，定量地估算焊接组合钢结构的疲劳寿命对于保证结构安全具有重要意义。通过假设疲劳裂纹在没有交变拉/压塑性应变积累的情况下不能扩展，其中一位作者基于代表疲劳裂纹驱动力的再拉伸塑性区产生（RPG）载荷确定了改进的有效应力强度因子范围Δ KRPG，并建议将Δ KRPG用作描述疲劳裂纹扩展行为的参数。为了预测疲劳裂纹的萌生和扩展行为，开发了以Δ KRPG为疲劳裂纹扩展参数的FLARP数值模拟程序。本文通过对平面角板焊接接头的疲劳裂纹扩展曲线和S-N曲线的计算结果与试验结果的比较，证明了FLARP对疲劳寿命的估算是准确的。此外，通过数值模拟，研究了平面外直线错边引起的弯矩对平面内节点板焊接接头疲劳强度的影响。
Many accidents are caused by fatigue in welded built-up steel structures, and so it is important to estimate the fatigue lives of such structures quantitatively for safety reasons. By assuming that fatigue cracks cannot grow without an accumulation of alternating tensile/compressional plastic strain, one of the authors identified an improved effective stress intensity factor range ΔKRPGbased on the re-tensile plastic zone generating (RPG) load, which represents the driving force for fatigue cracks, and suggested that ΔKRPGshould be used as the parameter to describe fatigue crack growth behavior. The “FLARP” numerical simulation code in which ΔKRPGis implemented as the fatigue crack growth parameter, was developed in order to predict fatigue crack initiation and propagation behavior. In this paper, it is demonstrated that FLARP gives accurate estimates for fatigue life by comparing the estimated fatigue crack growth curves andS–Ncurves with the experimental results for in-plane gusset welded joints, which are used in many welded steel structures. Moreover, the effect of induced bending moment due to the linear misalignment in the out of plane direction on the fatigue strength of in-plane gusset welded joints is investigated through numerical simulations.