基于压杆屈曲软化模型的桁架结构地震倒塌模拟  

Seismic collapse simulations of space truss structures based on compression buckling member model

作　　者：郑华冬 樊剑[2] 张耀庭[2] ZHENG Huadong;FAN Jian;ZHANG Yaoting(Department of Civil Engineering,Tsinghua University,Beijing 100084,China;College of Civil Engineering and Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]清华大学土木工程系,北京100084 [2]华中科技大学土木工程与力学学院,武汉430074

出　　处：《建筑结构》2020年第23期71-76,共6页Building Structure

基　　金：国家自然科学基金资助项目(51078166,51278218)。

摘　　要：强震作用下桁架结构中的杆件破坏形式一般为受压屈曲和受拉屈服,但是常用的双线性理想模型不能考虑杆件受压屈曲的情况。根据杆件受压屈曲时的物理行为推导了相应的显式表达式,并嵌入到显式动力分析方法中实现了空间桁架结构的地震倒塌分析。采用三种不同的杆单元模型,对一个三层空间桁架进行了动力弹塑性分析,并与ANSYS的计算结果进行了对比,发现杆单元模型对结构的响应影响较大,压杆屈曲软化模型既能模拟杆件受拉屈服,又可以考虑杆件受压非线性屈曲,能较合理地模拟结构的动力响应。最后分别对三种单元模型定义了相应的破坏准则,比较了高耸输电塔桁架结构在不同破坏准则下地震倒塌特征,该结构在压杆屈曲破坏准则下发生倒塌时的最小加速度峰值PGA为11.7m/s^2,具有较高的安全系数。The failure modes of truss structures subjected to strong earthquakes are buckling in compression or yielding in tension. However, the ideal bilinear model used in computaions fails to consider the nonlinear buckling behavior. Based on the physical behavior of the compression member under compression and buckling, an explicit expression was derived and embedded into the explicit dynamic analysis method to realize the seismic collapse analysis of the space truss structure. Three different truss member model were used to analyze the dynamic elasto-plasticity of a three-layer space truss, and the results were compared with those of ANSYS. It was found that the truss member model had a great influence on the response of the structure, and the developed compression member buckling and softening model could not only simulate the tensile yielding of the member, but also consider the nonlinear flexure of the member under compression, which could reasonably simulate the dynamic response of the structure. Finally, corresponding failure criteria were defined for each of the three unit models to compare the seismic collapse characteristics of the tower truss structure under different failure criteria. The PGA to the seismic collapse of this transmission tower under the buckling failure criterion is 11.7 m/s^2, which shows the structure is of high safety.

关 键 词：空间桁架结构 杆单元模型 破坏准则 显式动力分析 地震倒塌 

分 类 号：TU398.7[建筑科学—结构工程]