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This paper is concerned with the trends of stress fluctuations in dry granular materials as functions of the sample size D and of the grain diameter d. Results are obtained in the plateau regime of large axial deformation, during…

Disordered Systems and Neural Networks · Physics 2007-05-23 F. Adjémian , P. Evesque

Dislocation climb plays an important role in understanding plastic deformation of metallic materials at high temperature. In this paper, we present a continuum formulation for dislocation climb velocity based on densities of dislocations.…

Materials Science · Physics 2023-08-15 Chutian Huang , Shuyang Dai , Xiaohua Niu , Tianpeng Jiang , Zhijian Yang , Yejun Gu , Yang Xiang

We present a new framework to quantify the effect of hydrogen on dislocations using large scale three-dimensional (3D) discrete dislocation dynamics (DDD) simulations. In this model, the first order elastic interaction energy associated…

Materials Science · Physics 2018-01-31 Yejun Gu , Jaafar A. El-Awady

When metals are plastically deformed, the total density of dislocations increases with strain as the microstructure is continuously refined, leading to the strain hardening behavior. Here we report the fundamental role played by the…

Materials Science · Physics 2018-08-29 Ryan B. Sills , Nicolas Bertin , Amin Aghaei , Wei Cai

The present research is the first attempt to systematically quantify the dislocation-precipitate interaction in terms of applied shear stress, precipitate resistance, and the required time to reach the critical state of…

Materials Science · Physics 2017-11-07 Amirreza Keyhani , Reza Roumina

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

Isolated kinks on thermally fluctuating (1/2)<111> screw, <100> edge and (1/2)<111> edge dislocations in bcc iron are simulated under zero stress conditions using molecular dynamics (MD). Kinks are seen to perform stochastic motion in a…

Materials Science · Physics 2013-02-26 T. D. Swinburne , S. L. Dudarev , S. P. Fitzgerald , M. R. Gilbert , A. P. Sutton

In this study, we use discrete dislocation dynamics (DDD) simulation to investigate the effect of heterogeneous dislocation density on the transition between quasi-elastic deformation and plastic flow in face-centered cubic single crystals.…

Materials Science · Physics 2019-07-24 Xu Zhang , Jian Xiong , Haidong Fan , Michael Zaiser

It has been shown in experiments that self-climb of prismatic dislocation loops by pipe diffusion plays important roles in their dynamical behaviors, e.g., coarsening of prismatic loops upon annealing, as well as the physical and mechanical…

Materials Science · Physics 2019-05-21 Xiaohua Niu , Yejun Gu , Yang Xiang

Plastic deformation of metals involves the complex evolution of dislocations forming strongly connected dislocation networks. These dislocation networks are based on dislocation reactions, which can form junctions during the interactions of…

Materials Science · Physics 2022-08-22 Balduin Katzer , Kolja Zoller , Daniel Weygand , Katrin Schulz

The thermally activated motion of dislocations across fields of obstacles distributed at random and in a correlated manner, in separate models, is studied by means of computer simulations. The strain rate sensitivity and strength are…

Computational Physics · Physics 2018-07-27 Zhijie Xu , Catalin Picu

Dislocation slip is a general deformation mode and governs the strength of metals. Via discrete dislocation dynamics and molecular dynamics simulations, we investigate the strain rate and dislocation density dependence of the strength of…

Materials Science · Physics 2021-04-14 Haidong Fan , Jaafar A. El-Awady , Qingyuan Wang , Dierk Raabe , Michael Zaiser

Understanding plastic deformation of crystals in terms of the fundamental physics of dislocations has remained a grand challenge in materials science for decades. To overcome this, the Discrete Dislocation Dynamics (DDD) method has been…

Materials Science · Physics 2024-04-03 Nicolas Bertin , Wei Cai , Sylvie Aubry , Athanasios Arsenlis , Vasily V. Bulatov

The viscoplastic deformation (creep) of crystalline materials under constant stress involves the motion of a large number of interacting dislocations. Analytical methods and sophisticated `dislocation-dynamics' simulations have proved very…

Statistical Mechanics · Physics 2009-11-07 M. -Carmen Miguel , Alessandro Vespignani , Stefano Zapperi , Jerome Weiss , Jean-Robert Grasso

The gradient flow structure of the model introduced in [CG99] for the dynamics of screw dislocations is investigated by means of a generalised minimising-movements scheme approach. The assumption of a finite number of available glide…

Dynamical Systems · Mathematics 2016-03-01 Giovanni A. Bonaschi , Patrick van Meurs , Marco Morandotti

We study a one-dimensional model of a dislocation pileup driven by an external stress and interacting with random quenched disorder, focusing on predictability of the plastic deformation process. Upon quasistatically ramping up the…

Materials Science · Physics 2020-12-21 Mika Sarvilahti , Audun Skaugen , Lasse Laurson

This paper focuses on the connections between four stochastic and deterministic models for the motion of straight screw dislocations. Starting from a description of screw dislocation motion as interacting random walks on a lattice, we prove…

Analysis of PDEs · Mathematics 2020-09-11 Thomas Hudson , Patrick van Meurs , Mark A. Peletier

We report two-dimensional discrete dislocation dynamics simulations of combined dislocation glide and climb leading to `power-law' creep in a model aluminum crystal. The approach fully accounts for matter transport due to vacancy diffusion…

Mesoscale and Nanoscale Physics · Physics 2017-12-27 Shyam M. Keralavarma , Tahir Cagin , Tom Arsenlis , A. Amine Benzerga

In this paper, we present an improved framework of the spectral-based Discrete Dislocation Dynamics (DDD) approach introduced in [1,2], that establishes a direct connection with the continuum Field Dislocation Mechanics (FDM) approach. To…

Computational Physics · Physics 2018-04-04 Nicolas Bertin

We analyse how the sampling dynamics of distributions evolve in score-based diffusion models using cross-fluctuations, a centered-moment statistic from statistical physics. Specifically, we show that starting from an unbiased isotropic…

Machine Learning · Computer Science 2026-05-04 Sai Niranjan Ramachandran , Manish Krishan Lal , Suvrit Sra