大变形恒曲率多辊式止转筋矫直机构研究

Research of Bar Straightening Mechanism with Multi-roller Standstill Locking of Large Deformation and Constant Curvature

为有效提高钢筋生产效率和矫直质量,基于楔钳作用机理,提出一种多点作用辊式止转筋机构:两侧多辊对称压下,中间三辊具有曲率微调作用,针对不同直径的高强钢筋,形成匹配的大变形曲率,并处于楔钳夹持状态,保证后续矫直过程的止转筋。在对钢筋应力应变分析的基础上,采用工程弹塑性力学基本理论,推导出钢筋弹复过程的弹复扭矩方程,结合止转辊力学模型,建立止转筋变形协调方程,确立钢筋止转条件。解析结果表明:该多辊式止转筋机构的止转力矩大于钢筋弹复扭矩,实现钢筋矫直过程止转筋,从而可有效提高矫直精度。

In order to improve the production efficiency and straighten the quality of high strength steel bars, a roller standstill locking mechanism with multipoint action was proposed based on wedge clamp mechanism, which adopted symmetrical multi-railer in both ends and three rollers in the middle to realize fine-tuning of curvature. According to different diameter high strength steel bars, the matching large deformation curvature was formed. In the wedge clamp state, standstill locking of reinforcing steel bars in the subsequent straightening process was guaranteed. Based on the analysis of the stress and strain of the high strength steel bars, elastic recovery torque equation was deduced in reinforcing steel elastic recovery process using engineering elastic-plastic mechanics basic theory. Deformation coordinate equation of the reinforcing bars was established combined with standstill locking roller mechanical model and the standstill locking condition of reinforcing bars was established. Analytical results show that the standstill locking moment of multi-roller reinforcing mechanism is greater than the elastic recovery torque of steel bars, thus standstill locking of the high strength bars is achieved and the straightening precision can be improved effectively.