Abstract
An evaluation of different dislocation density-based strength models for a theory of micropolar single crystal plasticity is presented through detailed comparison with discrete dislocation dynamics simulations of a constrained thin film subjected to simple shear. The principal component of the evaluation is determining the most appropriate way to incorporate scale-dependent strengthening due to geometrically necessary dislocations (GNDs) within the model. We find that some models give results consistent with the discrete dislocation simulations, yet it is shown that models based on a generalized Taylor relation do not. Additionally, we briefly discuss the differences between models derived from unified (single) and independent (multiple) flow criteria, and demonstrate that single criterion models provide comparable predictive capability while introducing fewer nonlocal constitutive parameters.
| Original language | English |
|---|---|
| Pages (from-to) | 1935-1954 |
| Number of pages | 20 |
| Journal | Journal of the Mechanics and Physics of Solids |
| Volume | 61 |
| Issue number | 9 |
| DOIs | |
| State | Published - Sep 2013 |
| Externally published | Yes |
Funding
The authors would like to thank the reviewers for their many comments that helped improve the clarity of the paper. This work benefited from the support of Sandia National Laboratories through the Enabling Predictive Simulation Research Institute (EPSRI), and the Laboratory Directed Research and Development program. Sandia is a multiprogram laboratory operated by the Sandia Corporation, a Lockheed Martin Company, for the U.S. Department of Energy's National Nuclear Security Administration under DOE contract DE-AC04-94AL85000 . JRM also acknowledges fruitful discussions with Dr. D.J. Luscher and the support of Los Alamos National Laboratory , operated by Los Alamos National Security LLC under DOE Contract DE-AC52-06NA25936 . DLM gratefully acknowledges support of the Carter N. Paden, Jr. Distinguished Chair in Metals Processing in addition to NSF CMMI grant 1030103 on Methods for Atomistic Input into Initial Yield and Plastic Flow Criteria for Nanocrystalline Metals.
| Funders | Funder number |
|---|---|
| EPSRI | |
| National Science Foundation | 1030103 |
| U.S. Department of Energy | DE-AC04-94AL85000 |
| National Nuclear Security Administration | |
| Laboratory Directed Research and Development | |
| Los Alamos National Laboratory | DE-AC52-06NA25936 |
Keywords
- Crystal plasticity
- Discrete dislocation dynamics
- Geometrically necessary dislocations
- Micropolar
- Strain gradient
- Thin films