基于OpenSees平台的钢管混凝土结构力学性能数值模拟

基于非线性纤维梁-柱单元理论,以OpenSees为求解平台分别进行了钢管混凝土结构滞回曲线计算和弹塑性动力时程分析等数值模拟,计算结果与试验吻合良好。钢管内核心混凝土采用考虑钢管约束效应的应力—应变关系,钢材采用随动强化本构模型。在传统纤维模型法的基础上,通过直接在截面层次定义非线性剪切恢复力的方法建立了考虑非线性剪切效应的剪力墙结构数值模型,结果表明该模型能较好地模拟组合剪力墙的抗剪承载力、捏缩效应以及刚度退化等力学性能。对输入不同地震波下钢管混凝土框架体系的动力时程分析表明,基于OpenSees求解平台的非线性纤维模型法能够较好地模拟钢管混凝土框架结构的非线性动力特性。

Numerical Simulation on Mechanical Performance of Concrete Filled Steel Tubular Structures Based on OpenSees Plateform

The finite element（ FE） models were developed to analyze the hysteretic relationship and dynamic time history of the concrete-filled steel tubular（ CFST） structures based on nonlinear beam-column fiber element theory using OpenSees software. The numerical results are in good agreement with those of other experiments. The stress versus strain relationship of core concrete under confinement of the outside steel tubes was given and the material model of steel was simulated by kinematic hardening model. The shear force of fiber sections was simulated by defining the nonlinear shear restoring force in section level based on traditional fiber model. The presented model,which considered the shear effect,can effectively predict the maximum shear force,pinch effect and stiffness degradation of the composite shear walls. The analysis on the dynamic time history shows that the nonlinear fiber beam-column model can rationally and logically simulate the dynamic behavior of the CFST structures under different earthquake waves.