Abstract In this study, a straightforward method for evaluating damage and ultra-low-cycle fatigue (ULCF) life of high-rise steel frame structures under strong seismic loading at the material level was newly proposed on basis of inter-story drift measurement and mesoscopic fracture models. A mesoscopic ULCF model for cyclic loading was improved by considering both effects of strain amplitude and loading sequence, which was implemented into finite element software. Since elastic loading and unloading processes do not affect damage accumulation, four filtering methods for inter-story displacement data were proposed to improve computing efficiency without impeding simulation accuracy. An improved fracture model was integrated into ABAQUS using a user-defined subroutine, and a hybrid finite element analysis using both shell and beam elements was conducted, where filtered displacement was employed as input data. Experimental results of a shaking table test on a 1/3-scale 18-story steel frame conducted at E-Defense were employed to prove validity of the analysis method and fracture models. Comparison results show that the improved mesoscopic ULCF model can evaluate crack initiation of steel structures with acceptable accuracy.

中文翻译：

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基于细观断裂模型的高层钢框架损伤评估及超低周疲劳分析

摘要 在本研究中，基于层间位移测量和细观测量，新提出了一种直接评估高层钢框架结构在材料层面强地震荷载作用下的损伤和超低周疲劳（ULCF）寿命的方法。断裂模型。通过考虑应变幅度和加载序列的影响，改进了循环加载的细观 ULCF 模型，并将其实施到有限元软件中。由于弹性加载和卸载过程不影响损伤累积，提出了四种层间位移数据过滤方法，以在不影响仿真精度的情况下提高计算效率。使用用户定义的子程序将改进的断裂模型集成到 ABAQUS 中，并进行了使用壳单元和梁单元的混合有限元分析，其中过滤位移用作输入数据。在 E-Defense 进行的 1/3 比例 18 层钢框架振动台试验的实验结果被用来证明分析方法和断裂模型的有效性。对比结果表明，改进后的细观 ULCF 模型能够以可接受的精度评估钢结构的裂纹萌生。