熊缨
金属学报
在考虑载荷循环中裂纹尖端塑性变形导致柔度变化的基础上, 对结构钢SM400B进行了疲劳测试. 提出了基于两参量修正的裂纹驱动力模型: ΔK rm drive=(K max)n(ΔK^)1-n. 在预测应力比对裂纹扩展速率的影响时, 该模型比文献中报道的ΔK=K max-K min, ΔK eff=K max-K op和Δ K*=(K max)α(Δ K+)1-α更有效
关键词:
迟滞回线
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Compliance
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Fatigue crack growth
,
Crack tip
Liangbi LI
,
Zhengquan WAN
,
Zili WANG
,
Chunyan JI
金属学报(英文版)
doi:10.1016/S1006-7191(08)60090-3
Many factors influence the fatigue and crack growth behavior of welded joints. Some structures often undergo fairly large static loading before they enter service or variable amplitude cyclic loading when they are in service. The combined effect of both applied stress and high initial residual stress is expected to cause the residual stresses relaxation. Only a few papers seem to deal with appropriate procedures for fatigue analysis and crack growth by considering the combined effect of variable amplitude cyclic loading with residual stresses relaxation. In this article, some typical welded connections in ship-shaped structures are investigated with 3-D elastic-plastic finite element analysis. The effect of residual stress relaxation, initial residual stress, and the applied load after variable amplitude cyclic loading is revealed, and a formula for predicting the residual stress at hot spot quantitatively is proposed. Based on the formula, an improved fatigue procedure is introduced. Moreover, crack growth of typical weld joints considering residual stresses relaxation is studied.
关键词:
Residual stress relaxation
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