Modelling the mechanical and thermal properties of cellular materials from the knowledge of their architecture
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1188-LL06-05
Modelling the mechanical and thermal properties of cellular materials from the knowledge of their architecture Maire E.1, Caty O.1,2, Bouchet R.2, Loretz M.3 and Adrien J.1 1
Université de Lyon, INSA-Lyon, MATEIS CNRS UMR5510 F-69621 Villeurbanne, France ONERA Châtillon, 92322 CHATILLON, France. 3 Université de Lyon, INSA-Lyon, CETHIL Villeurbanne, France. 2
ABSTRACT This paper shows different examples where the architecture of cellular materials has been determined exactly using 3D X ray computed tomography. The images were then subsequently used to generate FE meshes reproducing the architecture as exactly as possible. The FE meshes where in turn used to simulate the mechanical (monotonous and fatigue compression) and the thermal (radiative properties) behavior of the studied materials. INTRODUCTION Playing games with the architecture of cellular materials opens thousands of different possible solutions for obtaining various properties. This large amount of solutions offered with a single composition by the arrangement of the solid and gaseous phase is extremely rich. The design engineers can start to imagine different combination of properties for a same given material. This important amount of possible solution can however possibly become a drawback: it is not humanly feasible to analyze experimentally all the different possibilities. In this context, modeling the properties of cellular materials from the knowledge of their architecture allows the different solutions to be screened. The more promising solutions can subsequently be analyzed experimentally and their properties verified. The problem is more and more tricky today because the properties required for certain applications are multi-functional. In a wide variety of applications, there is a need for the prediction of the mechanical properties but also and simultaneously of the thermal, acoustical, electrical, chemical properties... etc. All these properties are strongly affected by the structure. The present paper will show how one can determine with a common frame the thermal and mechanical properties of architectured cellular materials. This approach is based on the exact knowledge of the microstructure achieved using 3D images of the materials. X-ray tomography has appeared recently to be a very powerful tool allowing to characterize the architecture of structural materials [1, 2] or with a lower resolution, cellular materials [3-7]. The low X-ray absorption of these materials, composed of a large amount of air, permits large specimens to be studied using the technique. The second advantage of this method is to allow local and global large deformations to be imaged non destructively so the important buckling, bending or fracture events appearing during the eventual mechanical deformation can be visualized. The architecture has a strong effect on the behavior but the modeling methods proposed so far do not fully capture this effect. The seminal work by Gibson and Ashby [8] has permitted to underline that the relative density is a key pa
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