Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 8: SYM Micro- and Nanomechanics II
MM 8.5: Vortrag
Montag, 26. März 2007, 16:30–16:45, H16
Plasticity of thin polycrystalline metallic films: a discrete dislocation dynamics approach — •Jochen Senger1, Daniel Weygand1, Oliver Kraft1,2, and Peter Gumbsch1,3 — 1IZBS, Universität Karlsruhe (TH) — 2IMF II, Forschungszentrum Karlsruhe — 3IWM, Fraunhofer Institut für Werkstoffmechanik, Freiburg
Recent experimental observations (Spolenak et al, PRL 90, 096102, 2003) showed that the stress distribution in polycrystalline thin metal films upon thermal cooling or heating can be quite inhomogeneous. Stress variations were observed between grains and even within grains. To study such stress distributions, a parallel discrete dislocation dynamics (DDD) tool is employed, based the tool described in Weygand et al., Mod. Sim. Mater. Sci. Eng. 10 (2002) 437. The parallelization is achieved using OpenMP for shared memory platforms. The concept is based on a common data structure, where the individual calculation tasks are distributed among the CPUs. The main computational tasks, the interaction calculation between dislocation and the evaluation of the boundary conditions are performed on multiple CPUs and a very good scaling is achieved. The parallelized version of the DDD code is applied to the simulation of the small scale plasticity of polycrystalline thin films. The dislocation microstructure evolution and the resulting stress distributions are analysed and compared experiments and single grain simulations. If the calculated stresses of the multi grain simulations are averaged over areas corresponding to the experimental resolution, excellent agreement is found for stress amplitudes in simulation and experiment.