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12 Oct, 2018 - Seminary @IM2NP, Marseille (France)

posted Oct 11, 2018, 11:05 PM by Jonathan Amodeo

I'll give a presentation about the mechanics of nanoparticles at the IM2NP lab, in Marseille this morning @11 AM.

2 Oct, 2018 - Welcome to Javier Gonzalez and Benjamin Goument

posted Oct 2, 2018, 5:22 AM by Jonathan Amodeo

After 2 years of collaboration during his Master thesis, Javier joins the team to start a PhD thesis about dislocation microstructure in metallic and oxyde nanocrystals in collaboration with M. Perez (MATEIS, Lyon) and L. Dupuy (CEA SRMP, Saclay). Benjamin Goument is 5th INSA student, Materials Science department. He starts an intern in the group and his topic is about mechanical properties of rough nanosystems. Welcome !

3 Sept, 2018 - New article online in scripta : about the mechanics of porous silica nanoparticle

posted Sep 3, 2018, 3:56 AM by Jonathan Amodeo   [ updated Sep 3, 2018, 11:35 PM ]

William Gonçalves, Jonathan Amodeo, Julien Morthomas, Patrice Chantrenne, Michel Perez, Geneviève Foray, Christophe L. Martin "Nanocompression of secondary particles of silica aerogel", Scripta Materialia, Volume 157, December 2018, Pages 157-161

Please have the article for free (50 days) here: https://authors.elsevier.com/c/1Xf424r9TDtBoO


Fig. Sudden and continuous plastic shear events in silica nanoparticles subdomains.



August, 6th - New article online in Acta Materialia: shape effect in Si nanoparticles under compression

posted Aug 6, 2018, 6:04 AM by Jonathan Amodeo   [ updated Aug 7, 2018, 12:30 AM ]

D. Kilymis, C. Gerard, J. Amodeo, U.V. Waghmare and L. Pizzagalli "Uniaxial compression of silicon nanoparticles: An atomistic study on the shape and size effects" published in Acta Materialia is now online. It can be downloaded here. Here is the abstract. Please contact me for any further information (jonathan.amodeo@insa-lyon.fr).

Fig. Si nanoparticle can stabilize under various shapes. In this paper, several samples
are tested under compression using molecular dynamics simulations.
Abstract:
Molecular dynamics simulations were carried out to investigate the mechanical properties of silicon nanoparticles during uniaxial compression by a flat-punch indenter. We considered a large set of systems, with dimensions in the range 10 nme50 nm, and various shapes like cubic (perfect and blunt), spherical, truncated spherical, and Wulff-shaped, as well as two compression orientations and two temperatures. Thorough analyses of the simulations first revealed that the relation between nanoparticle size and strength, usually termed as ’smaller is stronger’, is critically dependent on the nanoparticle shape, at least for the investigated size range. For instance, a significant and size-dependent strength decrease is determined for facetted Wulff-like nanoparticles, but not for cubic or spherical systems for compression along < 100 >. We also found that the nanoparticle shape greatly influences plasticity. Several original plasticity mechanisms are obtained, among which the nucleation of half-loop V-shaped dislocation contained in two different {111} planes, dislocations gliding in unusual {110} planes, or the nucleation of partial dislocations in shuffle {111} planes. Our investigations suggest that plasticity properties are mainly governed by the localization of shear stress build up during elastic loading, and the geometry of surfaces in contact with indenters, these two characteristics being intimately related to the nanoparticle shape.

July, 11th - New article online in JNM: new insights about UO2 crystal plasticity

posted Jul 11, 2018, 1:06 AM by Jonathan Amodeo   [ updated Jul 11, 2018, 1:43 AM ]

Luc Portelette, Jonathan Amodeo, Ronan Madec, Julian Soulacroix, Thomas Helfer, and Bruno Michel "Crystal viscoplastic modeling of UO2 single crystal" published in Journal of Nuclear Materials is now online. It can be download here. Here is the abstract. Please contact me for any further information (jonathan.amodeo@insa-lyon.fr). Congrats Luc!


Fig. Modeling of the stress anisotropy in UO2 single crystal using CPFEM
Abstract: 
The viscoplastic behavior of uranium dioxide (UO2) single crystal is of great interest to perform predictive multiscale modeling of the nuclear fuel. Here, a viscoplastic model is built considering dislocation glide in ½<110>{100} and ½<110>{110} slip systems. The constitutive law parameters are determined adjusting the temperature dependency of the experimental critical resolved shear stress for both principal slip modes. Crystal plasticity finite element simulations of single crystal compression tests show a reasonable agreement with experimental viscoplastic anisotropy of UO2. However, for specific orientations where ½<110>{111} slip is observed experimentally, significant differences remain between experimental and computed compression stresses. Therefore, the role of ½<110>{111} slip is investigated based on a parametric study that provides new insights on UO2 plastic deformation. Several parameterizations of ½<110>{111} slip are tested highlighting the complexity of UO2 viscoplastic behavior. Significant improvements are still required to explain all simulation-experiment gaps.

June, 20th - @EMRS Spring, Strasbourg (France)

posted Jun 20, 2018, 8:45 AM by Jonathan Amodeo

I will give a talk about the influence of NP amorphous shell on their mechanical properties tomorrow morning (symposium AA Strength, plasticity, fracture and fatigue behaviour controlled by interfaces and grain boundaries) and present a poster about dislocation nucleation in MgO using NEB tomorrow evening.

June, 5th - New article online !

posted Jun 5, 2018, 12:23 AM by Jonathan Amodeo   [ updated Jun 5, 2018, 12:24 AM ]

The study "Dislocations and Plastic Deformation in MgO Crystals: A Review" has recently been published in the Special Issue Crystal Dislocations: Their Impact on Physical Properties of Crystals of the crystals magazine. 

Please find the article here


May, 14th - Acta and Scripta Materialia 2017 Outstanding Reviewer award

posted May 14, 2018, 5:52 AM by Jonathan Amodeo   [ updated Aug 10, 2018, 12:37 AM ]

21st Mar, 2018 - Welcome Javier Gonzalez !

posted Mar 21, 2018, 9:55 AM by Jonathan Amodeo

Javier just joined our group for his M2 internship about modeling dislocation vs rough surface interactions using MD. Welcome !

27 Feb, 2018 - PhD thesis on UO2 multi-scale modeling starting end of 2018

posted Feb 27, 2018, 9:30 AM by Jonathan Amodeo

http://mateis.insa-lyon.fr/sites/mateis.insa-lyon.fr/files/resume_these_thot_18-0052_eng.pdf

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