双阶屈服屈曲约束支撑的实现方法及数值分析

Implementation methods and numerical simulation of double-stage yield buckling restrained brace

屈曲约束支撑(buckling restrained brace,BRB)作为一种具备承载能力和耗能能力的阻尼器,在工程中得到了广泛应用。然而传统的屈曲约束支撑为避免发生低周疲劳破坏,在多遇地震工况下被设计为弹性支撑,无法耗散地震输入的能量。总结了分阶段屈服屈曲约束支撑的研究现状,并在此基础上通过改变一阶屈服耗能阻尼器的类型,提出了一阶阻尼器为摩擦型阻尼器的双阶屈服屈曲约束支撑(double-stage yield buckling restrained brace,DYBRB),分析了其构造形式、工作原理及力学模型,并利用有限元软件ABAQUS对其进行了模拟分析,通过改变一、二阶刚度比和摩擦阻尼器摩擦力与芯板屈服力比,对比不同支撑的等效黏滞阻尼系数。结果表明:该DYBRB的构造合理,滞回曲线饱满,具有明显的分阶段屈服能力,且在小位移下可以实现耗能,提高了支撑全过程耗能能力。一、二阶刚度比取4左右,摩擦阻尼器摩擦力比例取0.75~1时,DYBRB全过程的耗能能力较好。

Buckling restrained brace(BRB),as a kind of damper with both bearing capacity and energy dissipation capacity,it has been widely used in engineering.However,in order to avoid low cycle fatigue failure,the traditional buckling restrained braces are designed as elastic braces and can not dissipate the energy under frequent earthquakes.The research status of multi-stage buckling restrained brace is summarized.On this basis,by changing the type of the first-order yield energy dissipation damper,a double-stage yield buckling restrained brace(DYBRB)with friction damper as the first-order damper is proposed.The design,working principle and mechanical model of the structure are analyzed.The numerical model is simulated and analyzed by ABAQUS.By changing the multi-stage stiffness ratio and the ratio of friction force of friction damper to yield force of core plate,while the equivalent damping ratios are compared with the analysis results of different braces.The results show that the hysteretic curves of DYBRB are full.It has obvious phased yield capacity,and can realize energy consumption under small displacement,which improves the energy dissipating capacity of the whole process of the support.When the stiffness ratio of the initial stiffness and the second-stage stiffness is about 4,the bearing capacity ratio of friction force is between 0.75~1,and the DYBRB can achieve better energy dissipating capacity.