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为模拟预应力混凝土梁非线性分析时预应力钢筋的力学行为,基于随转坐标法和场一致性原则,导出能考虑几何及材料双非线性的预应力钢筋空间杆单元。该单元具有几何与材料两种非线性不耦合的特点。采用已有的实体退化壳单元模拟混凝土,根据预应力钢筋空间杆单元与混凝土实体退化壳单元在单元内的位移协调条件和虚功原理将两者组合成一个混合壳单元,并导出预应力钢筋空间杆元对混合壳单元切线刚度矩阵的贡献。由于预应力钢筋对结构的作用反映在混合单元模型内部,该单元模型并未增大计算规模。对一预应力混凝土T梁进行了破坏过程模拟,将计算结果与试验结果及其他文献计算结果进行了比较,表明建立的混合壳单元模型是正确的。
In order to simulate the mechanical behaviors of prestressing tendons in nonlinear analysis of prestressed concrete beams, a prestressed reinforced bar spatial bar element capable of considering both geometrical and material nonlinearities was derived based on the principle of coordinate rotation and field consistency. The unit has two characteristics of non-linear coupling of geometry and material. The existing degenerated shell elements are used to simulate the concrete. According to the displacement coordination condition and virtual work principle of the degenerated shell element of prestressed reinforced concrete bar and the degenerated shell element of concrete body, the two are combined into a mixed shell element, and the prestressed reinforcement Contribution of Spatial Bar Element to Tangential Stiffness Matrix of Mixed Shell Elements. Since the effect of prestressed reinforcement on the structure is reflected in the mixed element model, the element model does not increase the calculation scale. The failure process simulation of a prestressed concrete T-beam is carried out. The calculated results are compared with the experimental results and other literature calculations. The results show that the hybrid shell element model is correct.