Speaker
Description
The study of nano-particles (NPs) deformation has proved to be of high importance to understand elementary processes at small-scale, with several applications as in the fields of catalysis,nanomaterial engineering and medical imaging. Indeed, NPs are characterized by high yield strength and ductility, when compared to their bulk counterpart, that are mostly attributed to surface mechanisms. Usually, the two experimental techniques used to investigate NPs mechanics are microscropy-assisted compression tests and Molecular Dynamics (MD) simulations. While in-situ experimental tests remain complex to carry and expensive, MD has severe drawbacks, especially regarding the sample size and strain rate. In this study, we revisit the superposition method that relies on coupling Dislocation Dynamics (DD) and Finite-Element Modeling (FEM) to solve a boundary problem when applied to nano-objects. Here we use the Numodis DD nodal code with the Elmer elastic solver to deal with the interaction between dislocations and physical boundaries. Among others, El-Numodis accounts for the interactions between dislocations and free surfaces using the method developed by Weygand et al. [1]and uses a Kinetic Monte Carlo algorithm to statistically model the nucleation process from NPs corners and lateral surfaces. Load and displacement-control feedback loops were implemented to mimic regular experimental tests. Methodology, benchmarking and applications to the modeling of the MgO nanoparticles under compression will be presented.
REFERENCES
[1] D. Weygand, L. Friedman, E. Van Der Giessen, A. Needleman, Modelling and Simulations inMaterial Sciences and Engineering, 10(4) 437-468 (2002).
| Speaker Country | France |
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