Microstructural computational modeling of the mechanical behaviour of closed-cell foams: from tessellation-based to CT scan-based modeling

The mechanical behavior of closed cell metallic foams strongly depends on their geometry at the scale of cells and cell walls. Two approaches are proposed in this work to address this computationally:(i) a controlled geometrical description of foam morphology features by exploiting an advanced tessellation-based procedure, allowing to generate realistic microstructural geometry,(ii) a procedure allowing to extract geometrical features of a foam morphology based on image-based modelling using CT scans. The first approach proposes a methodology that allows the automated generation of RVEs with a detailed control of the microstructure, including of cell geometries. It is primarily based on an inclusions packing algorithm assisted by distance fields control. Such distance fields can subsequently be used to morph inclusions, producing generalized tessellations with the possibility of incorporating curved and irregular boundaries. 3D morphologies of closed cell foams are produced by extracting the geometry from a proper combination of distance field functions. The procedure allows controlling the cell size distribution, spatial cell wall thickness distribution (correlated or not with the cell size distribution), wall curvatures and/or defects. An automated 3D meshing tool for implicit geometries was exploited to produce high quality tetrahedral meshes from the generated implicit foam geometries. Representative volume element based simulations were performed using this approach to assess the different morphological features relative importance on the mechanical behaviour of ALPORAS. An original extension of this tool was incorporating the transformation of 3D geometry into a shell-based finite element model. This resulted in a significant gain in computation time and allowed for simulating compression test up to densification (being out of reach with 3D solid finite element models) showing a good qualitative match with experimental results from the literature.The second ap
Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished