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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。
Based on the composite-layered shell element, a computational model of thin-wall prestressed concrete structure is established and its mechanical behavior is analyzed. The shell element theory is first introduced and the shell element dispersion is applied to the thin-walled structure. The theory of layered theory was applied to the concrete in the shell, and the large deformed bar element was used to simulate the steel element in the shell. According to the displacement coordination condition of steel bar and concrete in shell element, the global transformation matrix is deduced and the two are combined into one unit. At the same time, the contribution of reinforcing bar to the overall stiffness matrix of composite shell element is deduced based on virtual work principle. The results of numerical examples show that the calculated results in this paper are in good agreement with the existing ones. The combined shell-element model can adapt to any arrangement of steel bars and can more fully reflect the mechanical effects of steel bars in concrete, Good, to make up for the shortcomings of commercial finite element software non-linear computing stability is poor. The combination-layered shell method provides an effective method of analysis for thin-wall prestressed concrete structures.