کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
797468 1467157 2007 26 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Gradient single-crystal plasticity with free energy dependent on dislocation densities
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
پیش نمایش صفحه اول مقاله
Gradient single-crystal plasticity with free energy dependent on dislocation densities
چکیده انگلیسی

This study develops a small-deformation theory of strain-gradient plasticity for single crystals. The theory is based on: (i) a kinematical notion of a continuous distribution of edge and screw dislocations; (ii) a system of microscopic stresses consistent with a system of microscopic force balances, one balance for each slip system; (iii) a mechanical version of the second law that includes, via the microscopic stresses, work performed during viscoplastic flow; and (iv) a constitutive theory that allows:

• the free energy to depend on densities of edge and screw dislocations and hence on gradients of (plastic) slip;

• the microscopic stresses to depend on slip-rate gradients.The microscopic force balances when augmented by constitutive relations for the microscopic stresses results in a system of nonlocal flow rules in the form of second-order partial differential equations for the slips. When the free energy depends on the dislocation densities the microscopic stresses are partially energetic, and this, in turn, leads to backstresses in the flow rules; on the other hand, a dependence of these stresses on slip-rate gradients leads to a strengthening. The flow rules, being nonlocal, require microscopic boundary conditions; as an aid to numerical solutions a weak (virtual power) formulation of the flow rule is derived.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of the Mechanics and Physics of Solids - Volume 55, Issue 9, September 2007, Pages 1853–1878
نویسندگان
, , ,