Lawrence Livermore National Laboratory employs a multiscale strength model, where strength depends on pressure, strain rate, temperature, and evolving dislocation density, that has proven to be an important tool to predict the strength of cubic and hexagonal symmetry materials. Model construction employs an information-passing paradigm to span from the atomistic to the continuum levels. Simulation methods in the overall hierarchy include density functional theory, molecular statics, molecular dynamics, dislocation dynamics, and continuum-based approaches. The model has been used to study the origins of strain hardening for cubic crystals, as well as the strength of micro-pillars, high-temperature nickel super alloys, and irradiated materials (among other applications).
The model is suited for large-scale computing. Over the last 15 years, ParaDiS, a large-scale dislocation dynamics simulation code to study the fundamental mechanisms of plasticity, has been developed at LLNL and has since become the field’s standard. LLNL also is at the leading-edge of capabilities available to do direct numerical simulation to look at influence of precipitates and offers high-energy diffraction microscopy experiments including expertise in both near-field (for spatially resolved lattice orientations) and far-field (for lattice strains) methods and the ability to instantiate models of as-measured microstructures. LLNL also offers expertise in combining diffraction microscopy and tomography data into constitutive models.
A public version of the code ParaDiS is freely available online. A more developed local version of the code is available at LLNL.
Name: Sylvie Aubry
- N. R. Barton, J. V. Bernier, R. Becker, A. Arsenlis, R. Cavallo et al., “A multiscale strength model for extreme loading conditions,” J. Appl. Phys. 109, 073501 (2011).
- A. Arsenlis, W. Cai, V.V. Bulatov, M. Rhee, M. Tang, T. Oppelstrup, M. Hiratani, G. Hommes, T. G. Pierce, "Enabling Strain Hardening Simulations with Dislocation Dynamics," Modelling Simul. Mater. Sci. Eng., 15, 553 (2007).
- S. Aubry and A. Arsenlis, "Use of spherical harmonics for dislocation dynamics in anisotropic elastic media," Modelling Simul. Mater. Sci. Eng. 21 065013, (2013).
- J. Crone, P. Chung, K. Leiter, J. Knap, S. Aubry, G. Hommes, and A. Arsenlis, "A multiply parallel implementation of finite element-based discrete dislocation dynamics for arbitrary geometries," Modelling Simul. Mater. Sci. Eng. 22, 035014, (2014).