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Geometrically-Compatible Dislocation Pattern and Simulations of Plastic Deformations in Crystalline and Amorphous Materials
14 Dez
14. Dezember 2018 17. Dezember 2018
short course (2 days)

Geometrically-Compatible Dislocation Pattern and Simulations of Plastic Deformations in Crystalline and Amorphous Materials

In this talk, we present two recent major developments on atomistic-informed multiscale simulations of plastic deformation in crystalline and amorphous solids.

In the first part of the talk, we shall discuss a recently developed multiscale dislocation pattern dynamics called Multiscale Crystal Defect Dynamics (MCDD), in which we put forth a novel concept of Geometrically-consistent dislocation pattern. Based on this notion and higher order Cauchy-Born rule, we have developed a systematic approach that uses the generic geometrically-compatible dislocation pattern in crystals to establish a multiscale crystal plasticity formulation, or an atomistic-informed crystal plasticity.

The main novelties of MCDD-based crystal plasticity are: (1) We have discovered a multiscale quasi-crystal patterns to represent geometrically-necessary dislocation pattern distribution, which is related to the original crystal structure, and (2) We adopt a fourth-order (four scales) Cauchy-Born rule-based strain gradient theory to model constitutive behaviors of various dislocation patterns and crystal defects, and we can simulate single crystal plasticity at sub-micro level or even higher levels. MCDD theory is an atomistic-informed macroscale or multiscale modeling theory that does not require any empirical formalism in the material theory.

In the second part of this talk we shall introduce a recent development of the Multiscale Shear-Transformation-Zone (STZ) theory that can simulate plastic deformation in amorphous solids. In the multiscale STZ theory, we developed a concept of the representative sampling cell (RS-cell) to extend the notion of the unit cell in crystalline materials to amorphous solids. Moreover, we have developed a coarse-grained Parrinello-Rahman molecular mechanics-based Cauchy-Born rule, and by combining it with the RS-cells, we have successfully simulated plastic deformations in a Lennard-Jones binary solid, a benchmark amorphous solid, at macroscale including the yield stress, flow stress, the Bauschinger effect, and plasticity under cyclic loadings, etc. at macroscale level without any empirical material parameters.

Referent/Referentin

Prof. Shaofan Li
Department of Civil and Environmental Engineering
The University of California-Berkeley

Veranstalter

The Graduate School MUSiC with the Sofja Kovalevskaja – Research Group

Termin

14. Dezember 2018 17. Dezember 2018
10:30 Uhr - 16:30 Uhr

Anmeldefrist

10. Dezember 2018

Kontakt

Xiaoying Zhuang
Institut für Kontinuumsmechanik
Appelstr. 11 A
30167 Hannover
Tel.: 0511 762 17834
Fax: 0511 762 5496
schulte@ikm.uni-hannover.de

Ort

Graduiertenschule MUSiC
Geb.: 3403
Raum: A501
MUSiC Seminarraum
Appelstr. 11 A
30167 Hannover
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