考虑应变率效应钢筋混凝土梁柱节点受力性能有限元分析

Finite element analysis on mechanical behavior of reinforced concrete beam-column joint considering strain rate effect

受材料率敏感性的影响,钢筋混凝土构件具有率敏感效应,其刚度、承载力在不同应变率水平下均有所不同。基于试验结果,考虑应变率效应对钢筋混凝土梁柱节点受力性能的影响,通过有限元分析软件ABAQUS,采用混凝土损伤塑性模型以及考虑强化的钢筋双折线模型,进行了不同加载速率下梁柱节点受力性能的有限元分析。分析结果表明:采用混凝土损伤塑性模型,可以有效地模拟钢筋混凝土梁柱节点在快速加载情况下的应变率效应,数值分析得到的梁端荷载-位移骨架曲线以及节点组合体快速加载情况下的承载力与试验结果基本吻合;快速加载下,受混凝土和钢筋率敏感性的影响,钢筋混凝土梁柱节点组合体的承载力得到提高;在屈服荷载之前,有限元分析得到的梁柱节点组合体刚度略高于试验值。

Due to the rate sensitivity of composed materials,reinforced concrete( RC) members exhibit rate-dependent behavior with varying stiffness and bearing capacity at different strain rates. On the basis of test results,considering the effect of strain rate,the mechanical behavior of RC beam-column joint at different loading speeds was studied by means of the finite element analysis software ABAQUS in this paper. The constitutive laws for concrete and reinforcement are plasticity damage model and bilinear hardening model,respectively. The results show that the effect of strain rate on RC beam-column joints can be effectively simulated by ABAQUS under high loading speed. The loaddeflection skeleton curves and shear carrying capacity of the RC beam-column joints obtained by finite element analysis are in good agreement with the test results. The shear carrying capacity of the RC beam-column joint is increased under high loading speed because of the strain rate dependence of concrete and reinforcing bars. It is also found that before yield,the stiffness of RC beam-column joint obtained by finite element analysis is higher than that obtained by test.