0000000000135215
AUTHOR
Fabrice Barbe
Modelling Polycrystalline Materials: An Overview of Three-Dimensional Grain-Scale Mechanical Models
International audience; A survey of recent contributions on three-dimensional grain-scale mechanical modelling of polycrystalline materials is given in this work. The analysis of material micro-structures requires the generation of reliable micro-morphologies and affordable computational meshes as well as the description of the mechanical behavior of the elementary constituents and their interactions. The polycrystalline microstructure is characterized by the topology, morphology and crystallographic orientations of the individual grains and by the grain interfaces and microstructural defects, within the bulk grains and at the inter-granular interfaces. Their analysis has been until recentl…
Tensile Failure of Bio-inspired Lattices with Different Base Topologies
In the last decades the use of cellular materials, either in the form of foams or lattices, has widely spread in engineering due to their specific properties, namely their high mechanical and multifunctional properties in terms of strength, stiffness, energy absorption, thermal and acoustic insulation at small weight compared to bulk materials. These features can be achieved, in the case of lattices, by designing their structure at different scales, both in two and three dimensions. Additionally, nowadays, complex desired geometries may be easily obtained thanks to consolidated and even recent technologies of production, especially Additive Manufacturing (AM) techniques. The aim of the pres…
An investigation into the fracture behaviour of honeycombs with density gradients
International audience; In this study we perform an experimental and computational investigation about the fracture behaviour of polymer honeycombs presenting gradients in terms of lattice density. Such lattice relative density variations are introduced with the aim of mimicking the micro-morphology encountered in some natural materials, such as several kinds of woods, which seems related to the ability of the corresponding macro-material to delay the propagation of fracture under certain conditions. Starting from the conclusions of previous computational analyses, we perform a few experimental tensile tests on ABS model honeycombs obtained by additive manufacturing, with the aim of getting…
Fracture of Honeycombs Produced by Additive Manufacturing
Publisher Copyright: © 2021 World Scientific Publishing Europe Ltd. Lattice materials, such as honeycombs, are remarkable in their ability to combine high stiffness, strength and toughness at low density. In addition, the recent and pervasive development of additive manufacturing technologies makes it easier to produce these cellular materials and opens new possibilities to improve their properties by implementing small modifications to their microstructure. Such developments open new opportunities towards the design of new classes of architectured materials. For example, recent computational studies have shown that honeycombs with lattice density gradients have a fracture energy under tens…
Elucidating the Effect of Bimodal Grain Size Distribution on Plasticity and Fracture Behavior of Polycrystalline Materials
The refinement of grains in a polycrystalline material leads to an increase in strength but as a counterpart to a decrease in elongation to fracture. Different routes are proposed in the literature to try to overpass this strength-ductility dilemma, based on the combination of grains with highly contrasted sizes. In the simplest concept, coarse grains are used to provide relaxation locations for the highly stressed fine grains. In this work, a model bimodal polycrystalline system with a single coarse grain embedded in a matrix of fine grains is considered. Numerical full-field micro-mechanical analyses are performed to characterize the impact of this coarse grain on the stress-strain const…