基于点-点单元的预应力混凝土结构仿真分析

Point-to-point element based simulation of pre-stressed concrete

基于增量形式的有限元法,建立接触摩擦问题的等效单元劲度 约束矩阵和等效结点荷载向量,提出一种利用点 点接触摩擦单元来模拟预应力钢筋混凝土中钢绞线与混凝土三维非线性接触模型.该模型以结点位移和接触应力作为基本未知量,考虑固定、滑动和张开3种接触条件,可以模拟预应力筋与混凝土之间的摩擦和滑动、张开和闭合;可用标准的有限元法将单元劲度矩阵和单元荷载向量集成到总劲度矩阵和总荷载向量中,计算过程简单,结果合理.

Based on the incremental FEM, by establishment of stiffnessconstraint matrixes for equivalent elements and loading vectors at equivalent nodes, a 3D nonlinear contact model was developed for simulation of the contactfriction interaction between prestressed bars and pores in concrete structure by use of the pointtopoint contact element. With the displacement and contact stress at nodes unknown, the model can simulate the friction, sliding, opening, and closing between prestressed bars and pores under fixed, sliding, and opening contact conditions. Besides, the element stiffness matrixes and loading vectors can be integrated into the general stiffness matrix and the total loading vector by use of the conventional FEM. The process of calculation is simple and the calculated result is reasonable.