屈曲约束支撑力学模型对比分析

Contrastive Analysis of BRB's Mechanical Models

屈曲约束支撑分析中主要有两种力学模型:平滑非线性的Bonc-Wen模型和简单双折线的模型。为了对比分析这两种模型在结构中模拟屈曲约束支撑的区别,结合试验模型进行了非线性时程分析。根据屈曲约束支撑构造特点,基于串联刚度模型构造了支撑的力学公式,由于一般连接点区域刚度较大,通过假设连接段刚度无限大来简化力学模型。同时引入超强系数来修正支撑屈服力以体现对支撑芯材强度提高作用。基于一个两层单跨人字屈曲约束支撑钢框架的试验模型,应用SAP2000有限元软件,分别建立Bonc-Wen和双线性模拟的屈曲约束支撑,并进行非线性动力时程分析。通过分析得出两种模型的顶点加速度、层间位移、层间位移角的响应,并与实验结构进行对比分析。结果表明:总体上两种模型差距不大,但屈服刚度平滑过度的Bonc-Wen模型比屈服刚度突变的双折线模型模拟屈曲约束支撑更为接近试验结果。

There are two main mechanical models for the analysis of Buckling Restrained Brace（ BRB） ： smooth and nonlinear Bonc-Wen model and Bilinear kinematic hardening model（ BKIN）. For contrastive analysis of the difference of simulating BRB in the structure between these two kinds of models,nonlinear time-history analysis had been made according to test model. According to the construction features of BRB,the BRB＇s mechanics formula was constructed based on series stiffness model. As the stiffness of ordinary connections region is usually enough large,mechanical model can be simplified by assuming that the stiffness of connecting piece is infinite. Meanwhile,by adopting super-strength coefficient support yield force can be amended to embody the function of support core materials strength increasing. An experimental model,based on2-stories single span herringbone BRB steel frame,use SAP2000 finite element software and respectively build Bonc-Wen and bilinear kinematic hardening model. Furthermore,nonlinear dynamic time-history analysis is conducted. Their peak acceleration,inter-story displacement and response of story drift are obtained by analysis. Then compared with test data,the results indicate that these two model＇s difference is not obvious generally. However,the Bonc-Wen model of yield stiffness smooth transition approaches the test data further than BKIN model on simulating BRB.