Geometrically projected discrete dislocation dynamics

Journal Article · Fri Jul 20 04:00:00 EDT 2018 · Modelling and Simulation in Materials Science and Engineering

DOI:https://doi.org/10.1088/1361-651X/aacf31· OSTI ID:1464207

Akhondzadeh, Sh ^[1]; Sills, R. B. ^[2]; Papanikolaou, S. ^[3]; Van der Giessen, E. ^[4]; Cai, W. ^[5]

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1. Stanford Univ., Stanford, CA (United States); Johns Hopkins Univ., Baltimore, MD (United States)
2. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
3. Johns Hopkins Univ., Baltimore, MD (United States); West Virginia Univ., Morgantown, WV (United States)
4. Univ. of Groningen, Groningen (The Netherlands)
5. Stanford Univ., Stanford, CA (United States)

Three-dimensional discrete dislocation dynamics methods (3D-DDD) have been developed to explicitly track the motion of individual dislocations under applied stress. At present, these methods are limited to plastic strains of about one percent or less due to high computational cost associated with the interactions between large numbers of dislocations. This limitation motivates the construction of minimalistic approaches to efficiently simulate the motion of dislocations for higher strains and longer time scales. In the present study, we propose geometrically projected discrete dislocation dynamics (GP-DDD), a method in which dislocation loops are modeled as geometrical objects that maintain their shape with a constant number of degrees of freedom as they expand. We present an example where rectangles composed of two screw and two edge dislocation segments are used for modeling gliding dislocation loops. We use this model to simulate single slip loading of copper and compare the results with detailed 3D-DDD simulations. We discuss the regimes in which GP-DDD is able to adequately capture the variation of the flow stress with strain rate in the single slip loading condition. In conclusion, a simulation using GP-DDD requires ~40 times fewer degrees of freedom for a copper single slip loading case, thus reducing computational time and complexity.

• Research Organization: Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1464207
• Report Number(s): SAND--2018-8383J; 666607
• Journal Information: Modelling and Simulation in Materials Science and Engineering, Journal Name: Modelling and Simulation in Materials Science and Engineering Journal Issue: 6 Vol. 26; ISSN 0965-0393
• Publisher: IOP Publishing
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Frank–Read source
dislocation dynamics
plasticity
single slip