基于有限元模拟的数控弯管过程轴力和弯矩的分析计算

A study of axial force and bending moment in tube numerical control bending based on finite element method

获取管材数控弯曲过程中的轴力和弯矩,有助于对成形机理的了解和后续的回弹分析,以及为选择设备和设计模具提供重要依据。提出了基于三维有限元模拟的数控弯管过程中轴力和弯矩的求解方法,详细阐述了其实现过程。采用该方法,分析了轴力和弯矩随弯曲角的变化特征以及工艺和材料参数对轴力和弯矩的影响规律:随着弯曲过程的进行,塑性变形区的轴力变化不大,弯矩呈指数关系变化,而弯曲变形区刚性端的轴力几乎线性递增,弯矩类似于阻尼正弦曲线变化;弯曲速度和材料强度系数的增大以及弯曲半径和硬化指数的减小会引起轴力和弯矩的增加。文中提出的方法也可推广应用于板材、其他型材和管材的弯曲。

To understand forming mechanism and analyze springbaek after unloading, and to select equipment and design die, it is necessary to obtain axial force and bending moment during the numerical control （NC） bending of tube. In this paper, a method of obtaining axial force and bending moment in tube bending process based on simulation results of the process using finite element method （FEM） has been put forward. Key procedures of this method have been represented in detail. Using the method, the features of axial force and bending moment in tube bending process, and influence laws of rotary velocity, bending radius, strength factor and hardenahility value on axial force and bending moment have been obtained. The results show that： During tube bending process, axial force acting on plastically deforming area changes a little, and bending moment acting on the area increases like an exponent line; axial force acting on rigidity end of the zone undergoing bending deformation increases linearly, and bending moment acting on the zone varies like a damped sine curve; the increase in rotary velocity and strength factor of material, and the decrease in bending radius and hardenability value will leads increases in axial force and bending moment. The method proposed in this paper also can be generalized to other bending processes of other parts, such as blank, profiled bar and tube.