薄壁管材连续矫直压扁量力学模型研究

RESEARCH ON A MECHANICAL MODEL OF THE FLATTENING INTERMESH FOR CONTINUOUS STRAIGHTENING OF THIN-WALLED TUBES

针对薄壁管材在连续矫直过程中大弯曲变形产生的截面扁化,需对管材截面进行压扁矫圆。在分析压扁矫圆变形过程和成形机理的基础上,结合薄壳弹塑性理论及其相关假设,确定了变形区的周向应变模型,进而完成了周向弯曲力矩的解析,运用经典卸载规律建立了薄壁管材截面矫圆的压扁量数学模型方程。通过有限元仿真分析证明了该模型的正确性和有效性,同时得到用初始截面径向最大位移量的2倍近似估算压扁量的方法,为继续深入研究矫直相关工艺参数的合理设置、完善薄壁管材矫直理论体系奠定基础。

It is well known that bending of the thin-walled tubes during continuous straightening causes ovalization in the tube cross-section, so it must be flattened to restrore roundness subsequently. Therefore, analyzing the deformation process and mechanism of flattening for setting round, the normal circumferential strain component is derived based on the elastic-plastic theory and relevant hypothesis of thin-walled members, then the circumferential bending-moment is obtained, and finally the mathematical model of the flattening intermesh for setting round is proposed using the classic unloading rule. In order to certify whether it is correct, we have done some dynamic simulations by FEA, and the results have shown that the model is correct and suitable, it was also found that the twice the maximum initial radial displacement can be used as a simplified estimate for the flattening intermesh. This paper can provide the basis for optimizing straightening technical parameters and completing the theory of thin-walled tube straightening.