基于数值模拟的无芯模旋压收口工艺

为深入研究旋压收口成形机理，并为实际工艺过程提供依据，文中建立了单旋轮无芯模旋压收口成形的大变形弹塑性有限元模型，使用有限元分析软件MARC，对旋压收口成形过程进行三维弹塑性有限元模拟．对旋压成形过程的变形机理及应力应变分布的分析结果表明，变形金属在旋轮与毛坯的接触区受三向压应力作用；从已变形区到未变形区，轴向拉应变逐渐过渡为压应变，径向压应变则过渡为拉应变．随着压下量的增加，等效应力增加，径向应力最大值均出现在口部直身以及过渡圆角内壁，最薄区域（拉裂危险截面）出现在过渡圆角位置．有限元模拟结果与实际旋压变形规律吻合良好，为收口旋压成形工艺的制定提供了理论依据．

Mandreless Neck-Spinning Technology Based on Numerical Simulation

In order to further investigate the neck-spinning mechanism and conduct practical manufacturing,the mandreless neck-spinning with a single roller is simulated based on the 3D elastic-plastic FEM(Finite Element Method) model by means of the FEM software MARC.The deformation mechanism and the distributions of stress and strain in the process of the mandreless neck-spinning are also analyzed.The results show that(1) the deformed metal in the contact zone between the roller and the blank is in a 3D compressive stress state;(2) the axial tensile strain is gradually transformed into the compressive strain from the deformed zone to the undeformed zone,while the radial compressive strain is transformed into the tensile one;(3) with the increment of the reduction of blank radius,the equivalent stress increases,and the maximum radial stress appears at the opening and the inner wall of the transitional circular zone;and(4) the thinnest area, namely,the dangerous position at which crack may occur,appears at the transitional circular zone.The simulated results accord well with the actual spinning process,which lays a theoretical foundation for the establishment of neck-spinning technology.