箍筋多边形成型建模及分析

Model and Analysis of Stirrup Polygon Forming

为明确箍筋多边形成型过程中其成型状态与箍筋拉力的关系,将箍筋拉弯过程分成先大挠度弯曲变形后拉直两个阶段;首先建立箍筋大挠度弯曲变形的悬臂梁力学模型,分析自由端上的压力与成型参数的关系;然后建立箍筋拉直的力学模型,得出箍筋拉力与位移的关系。根据上述力学模型,计算得到了在成型参数一定的情况下成型状态与成型拉力的关系图,给出了保证箍筋成型的拉力值。拉力波动方程分析表明在多边形箍筋角速度一定的情况下拉力的波动对箍筋成型状态的影响较小可以忽略不计。仿真表明:将箍筋拉弯过程看成先大挠度弯曲变形后拉直两个阶段,是获得箍筋成型状态与箍筋拉力定量关系的有效途径,建立的成型状态与成型拉力的关系图对多边形成型具有理论指导意义。

In order to determine the relationship between forming state and tension in the process of the stirrup polygon forming,the stretch bending process was divided into two stages: large deflection bending deformation and tension straightening. Firstly the cantilever beam mechanical model of the large deflection bending deformation of stirrup was set up to analyze the relationship between concentrated force on the free end and forming parameters.Then the mechanical model of stirrup tension straightening was set up and the relationship between stirrup tension and stretch displacement was obtained.According to the mechanics model,the diagram indicating the relationship between forming state and forming tension was obtained by calculation in the case that forming parameters were sure and the tension value to ensure stirrup forming was given. Tension fluctuation equation indicates that the tension fluctuation makes negligible influence on forming state in the case that polygon stirrup angular velocity is constant. Simulation shows that divideing the stretch bending process into two stages containing large deflection and tension straightening is the effective way to obtain the quantitative relationship between forming state and tension,and the forming model indicating the relationship between forming state and forming tension has theoretical guidance meaning for polygon forming.