带转动弹簧的杆单元平面钢结构弹塑性时程分析

Elastic-plastic Time-history Analysis of Plane Steel Structures with Two Rotational Springs

用两端带转动弹簧的杆单元代替一般的杆单元,提出了一种新的平面杆系钢结构动力弹塑性时程分析计算模型.根据梁柱半刚性连接的力学模型,提出了该类型连接在地震荷载作用下的恢复力模型.采用虚功原理,通过对单元转角-位移方程的修正,推导了这种计算模型的单元质量矩阵和刚度矩阵.采用Wilson-数值积分算法,进行了结构弹塑性时程分析计算,并编制了相应的分析计算程序.用此程序分析了连接的半刚性在罕遇地震作用下对钢框架结构动力性能的影响,并与有限元结果进行了比较.算例结果表明:连接的半刚性对结构动力性能的影响非常大,设计中应该考虑连接的半刚性影响.

A new calculation model for the elastic-plastic time-history analysis of plane steel structures was presented by replacing the general bar element with a new one, which had two rotational springs at its ends. Based on the mechanical model of beam-to-column semi-rigid connections, the restoring force model of this type connection was presented. Revising the rotation displacement equation, the mass matrix and stiffness matrix of this kind of structure were derived by virtual principle. The elastic-plastic time-history analysis of structure was made with Wilson-method, and an elastic-plastic time-history program for semi-rigid connected structures was worked out. The effects of semi-rigid connection on the dynamic behaviors of steel frames were analyzed under severe earthquakes, and parts of results were compared with those from other finite element method. The results of calculations show that the semi-rigid connection behavior influences greatly on the dynamic behaviors of steel structure, and it cannot be ignored in design.