Size-dependent energy in crystal plasticity and continuum dislocation models.

نویسندگان

  • Sinisa Dj Mesarovic
  • Samuel Forest
  • Jovo P Jaric
چکیده

In the light of recent progress in coarsening the discrete dislocation mechanics, we consider two questions relevant for the development of a mesoscale, size-dependent plasticity: (i) can the phenomenological expression for size-dependent energy, as quadratic form of Nye's dislocation density tensor, be justified from the point of view of dislocation mechanics and under what conditions? (ii) how can physical or phenomenological expressions for size-dependent energy be computed from dislocation mechanics in the general case of elastically anisotropic crystal? The analysis based on material and slip system symmetries implies the negative answer to the first question. However, the coarsening method developed in response to the second question, and based on the physical interpretation of the size-dependent energy as the coarsening error in dislocation interaction energy, introduces additional symmetries. The result is that the equivalence between the phenomenological and the physical expressions is possible, but only if the multiplicity of characteristic lengths associated with different slip systems, is sacrificed. Finally, we discuss the consequences of the assumption that a single length scale governs the plasticity of a crystal, and note that the plastic dissipation at interfaces has a strong dependence on the length scale embedded in the energy expression.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Multiscale Modeling of Structurally-Graded Materials Using Discrete Dislocation Plasticity Models and Continuum Crystal Plasticity Models

A multiscale modeling methodology that combines the predictive capability of discrete dislocation plasticity and the computational efficiency of continuum crystal plasticity is developed. Single crystal configurations of different grain sizes modeled with periodic boundary conditions are analyzed using discrete dislocation plasticity (DD) to obtain grain size-dependent stress-strain predictions...

متن کامل

Mesoscale model of plasticity

A framework for investigating plasticity phenomena and their dependence on the underlying physical and size-dependent mechanisms is developed. The framework is based on crystal plasticity and three-dimensional discrete dislocation dynamics analyses. Particularly, the mesoscale model couples continuum crystal plasticity framework with a set of spatio-temporal evolution equations for dislocation ...

متن کامل

Plastic Flow in a Composite: A Comparison of Nonlocal Continuum and Discrete Dislocation Predictions

A two-dimensional model composite with elastic reinforcements in a crystalline matrix subject to macroscopic shear is considered using both discrete dislocation plasticity and a nonlocal continuum crystal plasticity theory. Only single slip is permitted in the matrix material. The discrete dislocation results are used as numerical experiments and we explore the extent to which the nonlocal crys...

متن کامل

On thermodynamics of crystal plasticity

It is argued in this paper that there are three distinctive physical situations in which the continuum descriptions of crystal plasticity are conceptually different. They are determined by the properties of the random field of dislocation density. One of the cases corresponds to conventional plasticity theory. In this case the system energy possesses the energy density, and a formula for energy...

متن کامل

Non-local Continuum Thermodynamic Extensions of Crystal Plasticity to Include the Effects of Geometrically-necessary Dislocations on the Material Behaviour

The purpose of this work is the formulation of constitutive models for the inelastic material behaviour of single crystals and polycrystals in which geometrically-necessary dislocations (GNDs) may develop and influence this behaviour. To this end, we focus on the dependence of the development of such dislocations on the inhomogeneity of the inelastic deformation in the material. More precisely,...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Proceedings. Mathematical, physical, and engineering sciences

دوره 471 2175  شماره 

صفحات  -

تاریخ انتشار 2015