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针对地震作用下建筑结构钢的超低周疲劳断裂问题,在单调加载损伤模型的基础上,提出了一种适用于超低周循环加载情况下的损伤预测模型,并借助ABAQUS软件的用户自定义材料子程序模块,将建立的损伤预测模型引入到有限元分析程序中。然后分别依据建筑钢结构母材、热影响区和焊缝金属缺口试样的单调加载和超低周循环加载试验,标定了材料的损伤模型参数,并对比分析了缺口圆棒试样在不同加载方式下的损伤演化规律,损伤分析结果表明缺口圆棒试样的裂纹都产生于试样截面中心处,这与试验结果一致。最后,以钢框架梁柱焊接节点为研究对象,应用损伤模型分析了节点危险部位的损伤演化规律,数值模拟了节点的超低周疲劳断裂破坏过程,最终得到节点的疲劳寿命与试验结果吻合良好。
In view of the ultra-low cycle fatigue failure of structural steel under earthquake, based on the monotonic loading damage model, a damage prediction model suitable for ultra-low cycle loading is proposed. By means of user-defined ABAQUS software Material subroutine module, the established damage prediction model is introduced into the finite element analysis program. Then, based on the monotonic loading and the ultra-low cycle cyclic loading test of the base metal, the heat affected zone and the weld metal notch specimens respectively, the damage model parameters of the material were calibrated and the influence of different loading Mode of damage evolution, damage analysis results show that notched round bar specimen cracks are generated in the sample cross-section center, which is consistent with the test results. Finally, taking the welded joints of steel frame and column as the research object, the damage evolution of the dangerous parts of the joints is analyzed by using the damage model, and the failure process of the joints is numerically simulated. Finally, the fatigue life of the joints is in good agreement with the experimental results .