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 determination of the tangential stress-contact pressure relationship at a specimen-tool or target part-contactor contact surface. It is used in addition to the analysis of forming sequences or mechanical design. The specimen, or target part, used in the test is the same that the one involved in the studied forming sequence so that the physical and chemical 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 contactor. Then, the indenter is moved in contact with the generator line surface of the specimen or the target part. The computation of the tangential stress, contact pressure and effective plastic strain firstly with respect to the penetration, sizing length and front face angle and, secondly, with respect to the frictional variations are performed with a three-dimensional finite element model. An initial guide for the determination of the indenter length and front angle and indenter penetration in the specimen is proposed in order to define the most realistic tangential stress-contact pressure curves. Copyright (C) 1996 Elsevier Science Ltd