Numéro |
J. Phys. IV France
Volume 134, August 2006
EURODYMAT 2006 - 8th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading
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Page(s) | 1231 - 1237 | |
DOI | https://doi.org/10.1051/jp4:2006134187 | |
Publié en ligne | 26 juillet 2006 |
J. Cirne, R. Dormeval, et al.
J. Phys. IV France 134 (2006) 1231-1237
DOI: 10.1051/jp4:2006134187
The effect of strain rate on the die-drawing of polyoxymethylene at elevated temperatures
J. Mohanraj1, D.C. Barton1, C. G'Sell2 and I.M. Ward31 School of Mechanical Engineering, University of Leeds, Leeds, UK
2 École des Mines de Nancy, Nancy, France
3 School of Physics and Astronomy, University of Leeds, Leeds, UK
Published online: 26 July 2006
Abstract
In this paper we describe the intrinsic deformation
behaviour of polyoxymethylene in uniaxial tension, shear and plane strain
compression at 160C for strain rates from 10 - 3 to 1 s - 1.
In tension and shear, the deformation was determined by a novel
video-controlled testing system. There was a significant evolution of
volumetric strain in tension, indicating that damage mechanisms play a key
role in the plastic deformation behaviour. Post-mortem analysis on the shear
and compressed samples showed no evidence of dilatation. In uniaxial
tension, significant strain hardening was observed at high strains while
only a small increase of stress was observed in plane strain compression. In
shear, the plastic deformation occurred at constant stress. For the specific
case of die-drawing of polyoxymethylene, it has been shown with the aid of
small angle X-ray scattering that voids are nucleated at the die-entrance by
inhomogeneous shear deformation under negative (compressive) hydrostatic
stress. The growth of the voids is then aided by the tensile stresses that
are predominant in this process at die-exit. Extensive voiding occurred in
the oriented sample produced at high strain rates, as revealed by the
scanning electron microscopy, which affects the fracture strength and hence
the viable production speeds of the die-drawing process.
© EDP Sciences 2006