基于组合-分层壳元理论薄壁预应力混凝土结构的力学响应

基于组合-分层壳单元，建立薄壁预应力混凝土结构的计算模型，并对其力学行为进行分析。首先引入壳元理论，对薄壁结构进行壳元离散。并对壳元中的混凝土应用分层理论描述，对壳元中的钢筋单元采用大变形杆单元模拟。根据钢筋和混凝土在壳元内的位移协调条件，推导了整体转换矩阵后，将两者组合成一个单元，同时基于虚功原理推导了钢筋对组合壳元整体刚度矩阵的贡献。算例分析表明，本文方法的计算结果与已有的试验结果吻合良好，本文研究的组合壳元模型能适应钢筋的任意布置方式，能较全面地反映混凝土内钢筋的力学效应，数值计算稳定性良好，弥补了商用有限元软件非线性计算稳定性较差这一缺点。组合-分层壳元法为薄壁预应力混凝土结构提供了一种有效的分析方法。

Mechanical Response Analysis of Thin Walled Prestressed Concrete Structure Based on Combined-layered Shell Element

Based on combined-layered shell element method, the method of setting up computational model of the thin walled prestressed concrete structure is put forward and then mechanical behaviors are analyzed. After shell element theory is introduced, the thin walled structure is meshed in shell elements. Concrete in the shell element is modeled with layered shell theory and steel element in it is modeled by using large displacement bar element. According to their consistent displacement conditions, the global transposed matrix is calculated and they are combined to form a single shell element and then the contribution matrix of the steel to the combined shell element is deduced on basis of virtual principle. Through analysis of a classic example, the computational results are close with the available experiment results. It is shown that the structural performance and arbitrary disposal of the reinforced steel bars in concrete are considered comprehensively. The computation process is stable and the studied method remedies the deficiency of the weak stability of the finite element analysis softwares. The combined-layered shell element method is efficient and proper for analysis of the thin walled prestressed concrete structures.