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Shear girdling phenomenon in polymers
Author(s) -
Pae K. D.,
Silano A. A.
Publication year - 1978
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1978.070221027
Subject(s) - materials science , necking , polyoxymethylene , composite material , polypropylene , shear (geology) , shear stress , ultimate tensile strength , shear rate , hydrostatic pressure , pure shear , polymer , simple shear , mechanics , viscosity , physics
Hollow and solid specimens of polypropylene and solid specimens of polyoxymethylene exhibited an effect under torsional shear which is analogous to the necking usually observed in tensile tests. After reaching some critical shear strain in the postyield region localized shear deformation developed on the gauge length. As twisting was continued a dramatic decrease in the diameter of the cross section was observed. This torsional shear induced phenomenon was named girdling. The superimposition of hydrostatic pressure up to 6 kbar has a significant influence on the extent of girdle formation. Stress whitening, observed on the solid polyoxymethylene specimens was suppressed by the application of pressures greater than 1 kbar. Very large shear strains produced a ratchet‐type fracture surface on the solid specimens which indicates the presence of axial, radial, and tangential strains. Qualitatively, these results are supported by the finite deformation theory of elasticity.