Sb. Petersen et al., FRICTION IN BULK METAL-FORMING - A GENERAL FRICTION MODEL VS THE LAW OF CONSTANT FRICTION, Journal of materials processing technology, 66(1-3), 1997, pp. 186-194
Commercially available finite-element programs for the simulation of b
ulk metal-forming processes usually model the frictional restraint act
ing at the interface between the workpiece and the tools according to
the law of constant friction. Such description is often inadequate and
does not represent the state-of-the-art in tribology. In the present
paper it is shown that the application of the general friction model,
developed by Wanheim and Bay, involves a major improvement in the abil
ity to simulate processes where low tool-workpiece interface stresses
may prevail. This is confirmed by experimental and numerical investiga
tions into the upsetting of a semi-tapered specimen between parallel d
ies. Additionally, it has led to the proposal of a new ring-compressio
n test geometry intended to complement the conventional ring test for
the calibration of friction models under conditions where the normal s
tresses over considerable parts of the tool-workpiece interface may be
lower than the yield stress of the material. (C) 1997 Elsevier Scienc
e S.A.