ELASTOPLASTIC FINITE-ELEMENT ANALYSES OF AN UPSETTING-SLIDING TEST FOR THE DETERMINATION OF FRICTION AT MEDIUM AND HIGH CONTACT PRESSURE

The upsetting-sliding test is a friction test employed for the determi nation of the tangential stress-contact pressure relationship at a spe cimen-tool or target part-contactor contact surface. It is used in add ition to the analysis of forming sequences or mechanical design. The s pecimen, or target part, used in the test is the same that the one inv olved in the studied forming sequence so that the physical and chemica l characteristics of the contact involved by the test and sequence are the same. In the test, the contact pressure is exerted by an inclined front surface indenter which takes the place of the tool or the conta ctor. Then, the indenter is moved in contact with the generator line s urface of the specimen or the target part. The computation of the tang ential stress, contact pressure and effective plastic strain firstly w ith respect to the penetration, sizing length and front face angle and , secondly, with respect to the frictional variations are performed wi th a three-dimensional finite element model. An initial guide for the determination of the indenter length and front angle and indenter pene tration in the specimen is proposed in order to define the most realis tic tangential stress-contact pressure curves. Copyright (C) 1996 Else vier Science Ltd