基于共旋坐标和力插值纤维单元的RC框架结构连续倒塌构造方法  

A PROGRESSIVE COLLAPSE ANALYTICAL MODEL OF RC FRAME STRUCTURES BASED ON COROTATIONAL FORMULATION FOR FORCE-BASED FIBER ELEMENTS

作　　者：杜轲[1] 滕楠[1] 孙景江[1] 燕登 骆欢[1] DU Ke;TENG Nan;SUN Jing-jiang;YAN Deng;LUO Huan(Key Laboratory of Earthquake Engineering and Engineering Vibration, Institute of Engineering Mechanics,China Earthquake Administration, Harbin 150080, China)

机构地区：[1]中国地震局工程力学研究所地震工程与工程振动重点实验室,哈尔滨150080

出　　处：《工程力学》2019年第3期95-104,共10页Engineering Mechanics

基　　金：中国地震局工程力学研究所基本科研业务费项目(2016A05;2016B04);国家重点研发计划项目(2017YFC1500605);国家自然科学基金项目(51878631)

摘　　要：悬链机制会使钢筋混凝土框架结构产生有助于抵抗连续倒塌的附加承载能力,对结构抗连续倒塌能力至关重要。悬链机制处于几何大变形和材料非线性下降段的状态下,需要同时考虑材料非线性和几何非线性,因此对数值分析模型提出了更高的要求。为了解决基于力插值的纤维单元同时处理材料非线性和几何非线性的问题,该文采用基于共旋坐标法,提出了一种基于共旋坐标法的力插值纤维单元。该单元在形成中把变形体和刚体分开,局部坐标系的变形体内采用纤维划分考虑材料非线性,然后加上刚体位移,从局部坐标系到整体坐标系的转换中采用共旋坐标法以考虑几何非线性,给出了二维单元形成原理及非线性求解过程。实例分析结果表明基于共旋坐标法的力插值纤维单元能够较准确的模拟RC框架结构连续倒塌,梁机制阶段主要是材料非线性起控制作用,悬链线机制阶段主要是几何非线性起控制作用。Previous studies have shown that the catenary mechanism can bring RC frame structures additional load-bearing capacity to resist progressive collapse, and is essential to the progressive collapse resisting capacity of structures. The catenary mechanism occurs under the state of large geometric deformation and the material is in the nonlinear descent stage. Therefore, it is necessary to consider both material nonlinearity and geometric nonlinearity, which requires a more complicated numerical model. To co-process the material nonlinearity and geometric nonlinearity using fiber elements, a force interpolation fiber element based on co-rotational procedure is proposed in this paper. The element separates the deformable body from the rigid body in the formation. For the deformable body in the local coordinate system, the material nonlinearity is considered, and then the rigid body displacement is added. To consider the geometric nonlinearity in the transition from the local coordinate system to the global coordinate system, the co-rotational procedure is used. The formation principle of two-dimensional elements and the nonlinear solving process are given in the context. The example results show that the force interpolation fiber element based on the co-rotational procedure can accurately simulate the progressive collapse of RC frame structures. In the stage of beam mechanism, the material nonlinearity plays the key role, while whereas in the stage of catenary mechanism, the geometric nonlinear plays the key role.

关 键 词：RC框架结构 连续倒塌 悬链线机制 共旋坐标法 力插值纤维单元 

分 类 号：TU973.2[建筑科学—结构工程] TU311.4