dc.contributor.author Hutchinson, John W. dc.date.accessioned 2013-01-17T20:51:05Z dc.date.issued 2012 dc.identifier.citation Hutchinson, John W. 2012. Generalizing $J_2$ flow theory: Fundamental issues in strain gradient plasticity. Acta Mechanica Sinica 28(4): 1078-1086. en_US dc.identifier.issn 0567-7718 en_US dc.identifier.issn 1614-3116 en_US dc.identifier.uri http://nrs.harvard.edu/urn-3:HUL.InstRepos:10196727 dc.description.abstract It has not been a simple matter to obtain a sound extension of the classical $J_2$ flow theory of plasticity that incorporates a dependence on plastic strain gradients and that is capable of capturing size-dependent behaviour of metals at the micron scale. Two classes of basic extensions of classical $J_2$ theory have been proposed: one with increments in higher order stresses related to increments of strain gradients and the other characterized by the higher order stresses themselves expressed in terms of increments of strain gradients. The theories proposed by Muhlhaus and Aifantis in 1991 and Fleck and Hutchinson in 2001 are in the first class, and, as formulated, these do not always satisfy thermodynamic requirements on plastic dissipation. On the other hand, theories of the second class proposed by Gudmundson in 2004 and Gurtin and Anand in 2009 have the physical deficiency that the higher order stress quantities can change discontinuously for bodies subject to arbitrarily small load changes. The present paper lays out this background to the quest for a sound phenomenological extension of the rateindependent $J_2$ flow theory of plasticity to include a dependence on gradients of plastic strain. A modification of the Fleck-Hutchinson formulation that ensures its thermodynamic integrity is presented and contrasted with a comparable formulation of the second class where in the higher order stresses are expressed in terms of the plastic strain rate. Both versions are constructed to reduce to the classical $J_2$ flow theory of plasticity when the gradients can be neglected and to coincide with the simpler and more readily formulated $J_2$ deformation theory of gradient plasticity for deformation histories characterized by proportional straining. en_US dc.description.sponsorship Engineering and Applied Sciences en_US dc.language.iso en_US en_US dc.publisher Springer Verlag en_US dc.relation.isversionof doi:10.1007/s10409-012-0089-4 en_US dash.license OAP dc.subject strain gradient plasticity en_US dc.subject deformation plasticity en_US dc.subject $J_2$ flow theory of plasticity en_US dc.title Generalizing $J_2$ Flow Theory: Fundamental Issues in Strain Gradient Plasticity en_US dc.type Journal Article en_US dc.description.version Author's Original en_US dc.relation.journal Acta Mechanica Sinica en_US dash.depositing.author Hutchinson, John W. dc.date.available 2013-01-17T20:51:05Z dc.identifier.doi 10.1007/s10409-012-0089-4 * dash.contributor.affiliated Hutchinson, John
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