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Deformation, yield and fracture of polymers at high pressure
Author(s) -
Sauer J. A.
Publication year - 1977
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760170304
Subject(s) - materials science , hydrostatic pressure , crazing , yield (engineering) , deformation (meteorology) , composite material , polymer , stress (linguistics) , shear (geology) , shear stress , shear modulus , elastic modulus , ultimate tensile strength , hydrostatic stress , thermodynamics , finite element method , linguistics , philosophy , physics
The effects of hydrostatic pressure on the shear, compressive, and tensile stress‐strain behavior of both amorphous and crystalline polymers are reviewed and illustrated. For polymers with T g near to but below ambient temperature, there is a steep increase of modulus with pressure and, above some critical pressure, there is a lower rate of increase. The critical pressure is a linear function of the test temperature and, from its slope, one can deduce the pressure coefficient of T g . For many other polymers, there is a linear increase, over a wide pressure range, of elastic and shear moduli with pressure, and this is in accord, to a first approximation, with predictions of finite strain theory. Most all polymers investigated show a strong pressure coefficient of yield stress and in many cases this variation is linear over a wide pressure range, in accord with several pressure dependent yield criteria. To a considerable extent, the yield stress rise with pressure parallels that of the modulus, and this behavior is predicted by some yield theories. The effects of pressure on fracture stress and fracture strain are discussed. The results obtained depend on the polymer composition and structure and on the pressure medium. Consideration is also given to the effects of pressure on crazing and stress‐whitening.