板料表面摩擦系数均匀性对扩孔试验的影响

Influence of the Friction Coefficient Uniformity on the Hole Expansion Behavior

应用Dynaform软件对扩孔试验进行数值模拟,研究板料表面摩擦系数的变化对扩孔试验的影响。结果表明,随着板料与模具的摩擦系数增大,扩孔率减小,最终在凸模圆角壁部出现开裂。板料单面润滑可以降低试验所需的成形力,提高扩孔率。板料单面单边润滑扩孔时孔径会向摩擦系数小的一侧偏移;两边摩擦系数差距过大时,会导致在摩擦系数较大的一侧圆角壁部开裂。

In this paper,Dynaform was used to simulate the hole expanding test,and the influence of changingfriction coefficient of the plate surface on hole expansion behavior was studied.When the friction coefficient between plate and die increases,hole expansion ratio decreases,and finally cracks in the wall of the punch occurs.Single lubrication can reduce the forming force of the test and increase the hole expansion ratio.For single side lubrication,the hole diameter will be shifted to the small side of friction coefficient.When the friction coefficient difference between the two sides is too large,it can lead to the crack in the side with the larger friction coefficient.