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为了更精准地预测遭受强震的钢框架响应问题,提出一个循环荷载下的结构钢的单轴等效本构模型作为纤维梁单元模型,从而对强度和刚度的累积衰减和损坏进行研究。该模型包含3种骨架曲线、滞回准则、衰减准则,通过数学公式表达相关尺寸参数。通过使用由有限元软件ABAQUS提供的用户子程序接口UMAT,等效模型可被用作纤维梁单元模型。与包括结构静力循环荷载试验和结构非线性时程试验在内的传统试验结果相比,所提出的等效模型被证明是正确和可用的。最后,在一个四层框架中使用该模型来进行动力时程分析,并与传统的双线性模型进行比较。研究显示:所提出的模型为独立测试且其立体模型能够很好地模拟强度和刚度的衰减特性,精确地预测失效模式。此模型能很好地平衡计算精度和计算效率,为强震下钢框架的非线性分析提供了有力的工具。
In order to predict the response of the steel frame subjected to strong earthquakes more accurately, a uniaxial equivalent constitutive model of structural steel under cyclic loading is proposed as the fiber beam element model to study the cumulative attenuation and damage of strength and stiffness. The model includes three skeleton curves, hysteresis criteria, attenuation criteria, and expression of relevant dimensional parameters through mathematical formulas. By using the user subroutine interface UMAT provided by the finite element software ABAQUS, an equivalent model can be used as the fiber beam element model. The proposed equivalent model proves to be correct and available compared to traditional experimental results, including static cyclic loading tests of structures and non-linear structural tests of structures. Finally, the model is used in a four-layer framework for dynamic time history analysis and compared with the traditional bilinear model. The research shows that the proposed model is an independent test and its three-dimensional model can well simulate the attenuation characteristics of strength and stiffness and accurately predict the failure mode. This model can well balance the calculation accuracy and computational efficiency and provide a powerful tool for the nonlinear analysis of steel frames under strong earthquakes.