Challenges in crystal plasticity: from discrete dislocations to continuum models
- Stefan Sandfeld (University of Erlangen-Nuremberg, Germany)
- Lasse Laurson (Aalto University, Finland)
- Michael Zaiser (University of Erlangen-Nuremberg, Germany)
- Peter Dusan Ispanovity (Eötvös University, Hungary)
- Jerome Weiss (CNRS & University Grenoble Alpes, France)
The aim of this workshop is to bring together a number of experts from different disciplines, including but not limited to materials science and statistical physics, to benefit from the synergy of theoretical, computational and experimental studies in the field. These experts will include both junior and more senior active scientists. The main motivation for the meeting is to bring a synthesis from confronting three fundamental questions: first, what is the relevance of complexity and collective phenomena in plasticity? How is it reflected on larger scales than those that can be addressed on small-scale DDD simulations, both as one learns from experiments and as concerns models on the continuum scale, their formulations, validity and usefulness? The coupling between behaviour at different scales, in particular that between computational descriptions based on discrete dislocations and the corresponding continuum models, is crucial to allow one to scale up the relevant physics to macroscopic scales.
The microscopic-macroscopic coupling is in particular of relevance when one couples atomistic effects to the DDD-level: when is such physics important in changing the collective behavior? The relevant details could concern the dislocation mobility and the presence of dislocation slip, or the dislocation interactions at close ranges, or the presence of obstacles and impurities. In irradiated matter relevant for the nuclear industry time-dependent radiation debris is an example, but one faces here the general problem of an interface of statistical physics – the universality of critical phenomena like intermittent yielding – and the atomistic behavior. To this end the aim is also to explore parallels with modelling plasticity of amorphous materials, exhibiting similar heterogeneous dynamics even if the underlying microscopic mechanisms differ from those of crystalline solids.
Last, the current challenges in the numerical simulation of dislocation dynamics are a focus. This means computational techniques to speed up DDD simulations in general and in the presence of microscopic detail that has to be included like the interaction of dislocations with obstacles. It is also of interest how to do systematic coarse-graining from discrete dislocations to dislocation density based continuum models.
These three topics are crucial for the understanding where the dislocation physics will make progress in the next two to five years, including both where the interesting science would be and where the advances are needed in the numerical methods and in simulation infrastructure (parallelized codes and suitable architectures). The workshop will not have as a main focus the applications of numerical crystal plasticity though that is of main interest in computational materials design but we expect that this kind of research has a mid-term to long-range impact that should not be forgotten.
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