ISSN:
1435-1528
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Summary Second-order or cross effects are the result of quadratic tensor terms in the constitutive equations of isotropic elastic, viscous and visco-elastic media, which are required by the condition of tensor invariance of those relations. These effects are most pronounced when they are clearly separable from the first-order deformation, as in the case of second-order elongation and volume change of an elastic cylinder subject to a twisting moment (Poynting effect, dilatancy) or of second-order normal stress in the case of shear flow of polymeric liquids (Weissenberg effect). An accumulating second-order effect (Ronay effect) has been discovered in experiments on strain-hardening metal specimens in reversed torsion. While thePoynting effect vanishes at zero strain in elastic solids and theWeissenberg effect at zero velocity in polymeric fluids, the second-order strain increments accumulate in strainhardening media with the number of repeated torsion cycles. Hence their observation is simple and does not require the elaborate procedures necessary for the observation od second-order effects in elastic solids, viscous fluids and visco-elastic substances. It can be shown that the observed second-order strain accumulation (Ronay effect) is implied by thePrager-Hill stress strain-increment relation for strain-hardening media, combined with theKadshevich-Novozhilov formulation of kinematic hardening, provided that the arbitrary condition that strain-increment and stress change sign simultaneously is not imposed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01969166
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