板料成形摩擦特性的实验研究与有限元分析

Experimental study and finite element analysis of friction characteristics in sheet metal forming

采用MPX-2000盘一销式摩擦试验机研究了边界润滑条件下滑动速度与界面载荷对304不锈钢与SKDl1模具钢之间摩擦系数的影响。运用Matlab软件对实验数据进行处理分析，得出摩擦系数随滑动速度与界面载荷变化的规律，建立了基于滑动速度与界面载荷的变摩擦系数模型。并对典型U形件进行了实际冲压实验与有限元仿真，比较了定摩擦系数模型和变摩擦系数模型的回弹预测结果与测量值之间的误差。分析结果表明：滑动速度为30．615-44．22mm·s^-1时，304不锈钢与SKDll模具钢之间的摩擦系数随滑动速度的增加而逐渐减小；界面载荷为2．038-4．076MPa时，摩擦系数随界面载荷的递增而递减，且随着载荷的增加，摩擦系数减小的趋势逐渐变缓。采用修正后摩擦模型的回弹预测结果与测量值之间误差较小，预测精度较高。

The effect of sliding speed and interface load on friction coefficient under boundary lubrication condition of 304 stainless steel and SKD11 die steel was studied by using MPX -2000 disc-pin friction tester. The experimental data was analyzed by using Matlab software and the change law of friction coefficient varies with the sliding speed and interface load was obtained. The variable friction coefficient model was established based on sliding speed and interface load. Stamping experiment and finite element simulation of U-shape bending were conduc- ted. The error between the predicted and measured results of springback based on constant friction coefficient model and variable friction co- efficient model was compared. The results show that the friction coefficient between 304 stainless steel and SKD11 die steel decreases gradu- ally with the increase of sliding peed when sliding peed is between 30. 615 and 44. 22 mm · s- 1 ; the friction coefficient decreases gradually with the increase of interface load, and the decreasing trend is slowing down when the interface load is between 2. 038 and 4. 076 MPa. The error between the predicted results and the measured values of the modified friction model is small, and the prediction precision is high.