Green's function molecular dynamics meets discrete dislocation plasticity

S. Parayil Venugopalan, Martin H. Mueser, Lucia Nicola

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    Abstract

    Metals deform plastically at the asperity level when brought in contact with a counter body even when the nominal contact pressure is small. Modeling the plasticity of solids with rough surfaces is challenging due to the multi-scale nature of surface roughness and the length-scale dependence of plasticity. While discrete-dislocation plasticity (DDP) simulations capture size-dependent plasticity by keeping track of the motion of individual dislocations, only simple two-dimensional surface geometries have so far been studied with DDP. The main computational bottleneck in contact problems modeled by DDP is the calculation of the dislocation image fields. We address this issue by combining two-dimensional DDP with Green's function molecular dynamics. The resulting method allows for an efficient boundary-value-method based treatment of elasticity in the presence of dislocations. We demonstrate that our method captures plasticity quantitatively from single to many dislocations and that it scales more favorably with system size than conventional methods. We also derive the relevant Green's functions for elastic slabs of finite width allowing arbitrary boundary conditions on top and bottom surface to be simulated.
    Original languageEnglish
    Article number065018
    Number of pages20
    JournalModelling and Simulation in Materials Science and Engineering
    Volume25
    Issue number6
    DOIs
    Publication statusPublished - 2017

    Keywords

    • Green's functions
    • dislocation dynamics
    • contact mechanics

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