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We present a time-dependent Ginzburg-Landau model of nonlinear elasticity in solid materials. We assume that the elastic energy density is a periodic function of the shear and tetragonal strains owing to the underlying lattice structure.…

Statistical Mechanics · Physics 2009-11-10 Akira Onuki , Akira Furukawa , Akihiko Minam

The plasticity transition at the yield strength of a crystal typically signifies the tendency of dislocation defects towards relatively unrestricted motion. For an isolated dislocation the motion is in the slip plane with velocity…

Materials Science · Physics 2020-01-15 Péter Dusán Ispánovity , Stefanos Papanikolaou , István Groma

A continuum theory based on thermodynamics has been developed for modeling diffusional creep of polycrystalline solids. It consists of a coupled problem of vacancy diffusion and mechanics where the vacancy generation/absorption at grain…

Materials Science · Physics 2019-11-18 M. Magri , G. Lemoine , L. Adam , J. Segurado

By means of linear theory of elastoplasticity, solutions are given for screw and edge dislocations situated in an isotropic solid. The force stresses, strain fields, displacements, distortions, dislocation densities and moment stresses are…

Materials Science · Physics 2007-05-23 Markus Lazar

We study a continuum model of dislocation transport in order to investigate the formation of heterogeneous dislocation patterns. We propose a physical mechanism which relates the formation of heterogeneous patterns to the dynamics of a…

Materials Science · Physics 2018-08-29 Ronghai Wu , Daniel Tüzes , Péter Dusán Ispánovity , István Groma , Michael Zaiser

In this paper we analyse the behaviour of a pile-up of vertically periodic walls of edge dislocations at an obstacle, represented by a locked dislocation wall. Starting from a continuum non-local energy $E_\gamma$ modelling the…

Analysis of PDEs · Mathematics 2016-06-07 Adriana Garroni , Patrick van Meurs , Mark Peletier , Lucia Scardia

Dislocation based modeling of plasticity is one of the central challenges at the crossover of materials science and continuum mechanics. Developing a continuum theory of dislocations requires the solution of two long standing problems: (i)…

Materials Science · Physics 2016-06-29 Thomas Hochrainer

We study the properties of strain bursts (dislocation avalanches) occurring in two-dimensional discrete dislocation dynamics models under quasistatic stress-controlled loading. Contrary to previous suggestions, the avalanche statistics…

The elastic energy functional of a system of discrete dislocation lines is well known from dislocation theory. In this paper we demonstrate how the discrete functional can be used to systematically derive approximations which express the…

Materials Science · Physics 2015-12-02 Michael Zaiser

We consider a system of parallel straight edge dislocations and we analyse its asymptotic behaviour in the limit of many dislocations. The dislocations are represented by points in a plane, and they are arranged in vertical walls; each wall…

Analysis of PDEs · Mathematics 2015-06-05 Marc Geers , Ron Peerlings , Mark Peletier , Lucia Scardia

Here we present a model to study the micro-plastic regime of a stress-strain curve. In this model an explicit dislocation population represents the mobile dislocation content and an internal shear-stress field represents a mean-field…

Materials Science · Physics 2015-06-05 P. M. Derlet , R. Maaß

We compute displacement and stress due to a normal fault by means of two-dimensional plane-strain finite-element analysis. To do so, we apply a system of forces to the fault nodes and develop an iterative algorithm serving to determine the…

Geophysics · Physics 2007-05-23 Antonietta Megna , Salvatore Barba , Stefano Santini

A possible approach to description of the non equilibrium system has been proposed. Based on the Fokker-Plank equation in term of energy for non equilibrium distribution function of macroscopical system was obtained the stationary solution…

Statistical Mechanics · Physics 2008-08-08 Bohdan Lev

The technique of distributed dislocations proved to be in the past an effective approach in studying crack problems within classical elasticity. The present work is intended to extend this technique in studying crack problems within…

Mathematical Physics · Physics 2017-07-04 P. A. Gourgiotis , H. G. Georgiadis

Certain systems with slow driving and avalanche-like dissipation events are naturally close to a critical point when the ratio of two energy scales is large. The first energy scale is the threshold above which an avalanche is triggered, the…

Statistical Mechanics · Physics 2015-06-25 Barbara Drossel

In this paper we characterise the equilibrium measure for a nonlocal and anisotropic weighted energy describing the interaction of positive dislocations in the plane. We prove that the minimum value of the energy is attained by a measure…

Analysis of PDEs · Mathematics 2017-12-19 Maria Giovanna Mora , Luca Rondi , Lucia Scardia

A three-dimensional continuum dislocation theory for single crystals containing curved dislocations is proposed. A set of governing equations and boundary conditions is derived for the true placement, plastic slips, and loop functions in…

Materials Science · Physics 2015-06-12 Khanh Chau Le

The static stress needed to depin a 2D edge dislocation, the lower dynamic stress needed to keep it moving, its velocity and displacement vector profile are calculated from first principles. We use a simplified discrete model whose far…

Materials Science · Physics 2009-11-10 A. Carpio , L. L. Bonilla

In this paper, we present a dislocation-density-based three-dimensional continuum model, where the dislocation substructures are represented by pairs of dislocation density potential functions (DDPFs), denoted by $\phi$ and $\psi$. The slip…

Materials Science · Physics 2015-09-23 Yichao Zhu , Yang Xiang

An algorithm is constructed to derive a small momentum expansion for two-loop two-point diagrams in all cases where, due to the presence of physical thresholds, there are singularities at zero external momentum. The coefficients of this…

High Energy Physics - Phenomenology · Physics 2009-10-28 F. A. Berends , A. I. Davydychev , V. A. Smirnov , J. B. Tausk