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Measuring the friction coefficient in the case of plastification of metals by elastomers
Author(s) -
Pawelski Hartmut
Publication year - 1998
Publication title -
steel research
Language(s) - English
Resource type - Journals
eISSN - 1869-344X
pISSN - 0177-4832
DOI - 10.1002/srin.199801466
Subject(s) - materials science , elastomer , composite material , lubrication , inlay , friction coefficient , aluminium , hydrostatic equilibrium , reciprocating motion , natural rubber , coefficient of friction , shear (geology) , metallurgy , mechanical engineering , engineering , quantum mechanics , gas compressor , physics
The friction measuring apparatus according to O. Pawelski, which is based on the strip drawing experiment, is used to determine friction coefficients in plastic shaping of metals. By implementing elastomer inlays into the drawing cheeks the same principle has been applied to the contact between metals and elastomeric media. The plastification of metal by the extremely shear‐weak elastomer is possible, because it is completely constrained with metal, so that a sufficiently high hydrostatic pressure in the inlay is generated. Elementary theory in combination with FEM showed that the friction coefficient, calculated using only the global static equilibrium of forces, is in very good approximation with simply the mixture of the friction coefficient between metal strip and elastomer and the friction coefficient between metal strip and drawing cheek weighted with the corresponding contact areas. Drawing experiments with aluminium 99.5 or steel St 37 and polyurethane or soft rubber were carried out. The important influence of lubrication and roughness of the metal strip on the friction coefficient was investigated.