Sensitivity analysis of friction coefficient testing in sheet metal forming

Friction coefficient has an important effect on the finite element computation results. The universal testing way is based on the Duncan method. In the process, the friction column diameter and friction angle have large effects on the friction coefficient calculation. Therefore, a new friction coefficient measuring apparatus was designed to test the effects of the friction column diameter and friction angle on the friction coefficient calculation. The test results show that with the increase of the column diameter and angle, the calculation value of friction coefficient decreases gradually and trends towards the real value finally. Based on the test and the FEM simulation, it is found that when the diameter is larger than 30 mm and the angle is larger than 90°, the calculation value of friction coefficient is exact enough to be used in the blank sheet FEM simulation.