梁柱焊接节点考虑损伤累积的疲劳剩余强度计算

Residual Strength of Beam-column Welded Joints under Low Cycle Fatigue Considering Damage Accumulation

对典型梁柱焊接节点低周疲劳实验进行了考虑损伤累积动态演化的有限元模拟,以获得其剩余强度/寿命。模拟从材料层面出发,引入焊材和钢材的考虑损伤演化的动态本构关系,利用ANSYS中的APDL(ANSYS Parametric Design Language)语言编译有限元子程序,实现了应力应变场与损伤累积效应的耦合分析。计算所得的滞回曲线、变形发展以及疲劳寿命等与实验结果吻合较好,证明该模型及分析方法在模拟损伤退化和破坏预测方面具有可靠的准确性。通过有限元计算可得到焊接节点中承受低周疲劳载荷后损伤变量的分布,其结果可为震后结构的鉴定和加固提供可靠依据。

Damage accumulation analysis of a typical beam-column welded joint tests were conducted to study its mechanical behaviour and to obtain the residual strength after low-cycle fatigue loading. Material constitutive model considering dynamic damage accumulation are adopted in the finite element analysis to study the coupled development of both strain and damage. The FE model is established using the ANSYS APDL（ ANSYS Parametric Design Language）. Results from FEA are found to be in good agreement with the experiment results in terms of the hysteretic curve,failure mode,and the residual strength. The validated model is proved to be reliable in predicting the mechanical behaviour and the remaining strength of welded joints under low-cycle fatigue. The quantitative results of damage distribution in the member may provide useful basis for evaluaiton and repair of structural members after earthquake loadings.