球形件反复拉深成形有限元模拟及应力应变分析

Numerical simulation and stress-strain analysis of spherical shell forming by repetitive deep drawing

采用Marc软件对球形件一次拉深成形和反复拉深成形工艺进行数值模拟,得到了成形过程中的应力-应变曲线。结果表明,反复拉深成形时,球底区径向应力远小于一次拉深成形,周向应力表现为压应力和较小的拉应力,使得球底区厚向应变明显小于一次拉深,且反复拉深次数越多,厚向应变越小。反复拉深成形可改变制品成形过程中的应力应变状态,抑制壁厚减薄,能够提高板材的成形极限。经3次反复拉深,可实现近似等壁厚成形。并设计成形实验模具,对球形件3次反复拉深成形工艺进行实验验证,成形出了质量良好的零件。

By using Marc software,the once drawing and repetitive deep drawing are simulated and analyzed.The stress-strain states of the forming processes are obtained from the simulation and the comparative analysis with the results of different drawing models is performed.The spherical radial stress of the repetitive drawing is far less than that of the once deep drawing.The circumferential stress in the spherical bottom is shown as compressive stress and low tensile stress,which makes the thickness strain in the spherical bottom is smaller than that of the once drawing.The more times of the repetitive drawing,the smaller the thickness strain will be.The repetitive deep drawing process can change the state of stress and strain,which can inhibit the reduction of wall thickness.So that the forming limit is improved.Three-time drawing can achieve nearly the same wall thickness.The experimental die for repetitive deep drawing is designed.The experimental study is carried out and the spherical pieces with better quality are formed.