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Sujet de stage / Master 2 Internship

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Fracture properties of bone-inspired mechanical metamaterials: toward lightweight and resistant solids

Contact: BONAMY Daniel, , daniel.bonamy@cea.fr, +33 1 69 08 21 14
Summary:
The internship is part of a research project aiming at developing a new class of porous meta-materials with a random architecture inspired by that of bones, to achieve high performance in terms of both lightness and resistance to fracture.
Possibility of continuation in PhD: Oui
Deadline for application:30/03/2019

Full description:
The quest toward high-performance materials combining lightness and mechanical strength gave rise to a flurry of activity: desire to reduce CO2 emissions and develop fuel-efficient vehiclesin the transport industries for instance. In this context, meta-materials or architectured materials offer considerable potential (e.g. micro-lattice invented at Caltech and produced by Boeing) and significant progresses have been achieved recently.
The routes explored till now have focussed mainly on periodic architectures.
The routes explored so far have mainly focused on periodic architectures. This project aims to explore random architectures, imitating that of bones, with specific scale invariant statistical properties (fractals). Particular attention will be paid to the consequences of such a random structure in terms of "risks", ie statistical fluctuations around the average failure behavior. The ultimate goal is to provide rigorous rationalization tools to define one or more optima in terms of lightness, crack resistance and risk (as defined above) in this new class of materials.
Our previous research has provided some formalisms, at the interface between continuum mechanics and statistical physics, which allow (in simple cases) to explicitly take into account the effect of microstructure inhomogeneities (or its discrete nature) on behavior. in macroscopic rupture and its statistical fluctuations. We will seek to adapt this formalism to the study of our random metamaterials. The project will rely on numerical approaches based on random network models of increasing complexity. Particular attention will be paid to a correct characterization of the statistical fluctuations around the average breaking behavior. The approach will then be confronted with experiments carried out on fractal fractal porosity 2D printed samples using an original experimental device developed in our laboratory and giving access to both the tenacity and its statistical fluctuations
Technics/methods used during the internship:
Discrete element modeling, statistical analysis, numerical simulations, methods of experimental mechanics (PhD), additive printing (PhD)

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