Multi-scale foam : 3D structure/compressive behaviour relationship of agglomerated cork

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. This is an author-deposited version published in: https://sam.ensam.eu Handle IDKeywords: Multi-scale microstructure Cellular material Cork agglomerate X-ray microtomography Mechanical behaviour a b s t r a c tThis study focuses on the microstructural aspects of a cork-based by-product known as agglomerated cork and its influence on the compressive mechanical behaviour. The material consists in granulates of a natural polymeric foam -cork -mixed together with a small quantity of a bio-sourced resin.Optical and scanning electron microscopy (SEM) are first used to investigate on the bead geometry and placement and interfaces arrangement. Then X-ray computed tomography allows to study the spatial arrangement of agglomerated cork microstructure and hence to complete and confirm 2D observations. 2D and 3D observations show a transverse anisotropic material which is confirmed by the mechanical tests. SEM pictures demonstrate an intricate and heterogeneous material. Microtomography confirms the presence of macroporosities between cork granulates having a mean volume around 0.1 mm 3 . Cork cell specific geometry is also confirmed. The volume of those cells lies around 10 −5 mm 3 . Finally quasi-static compression tests are run to establish a link between microstructure and mechanical behaviour thanks to digital image correlation (DIC). Cork agglomerate demonstrates strong strain localisation at its surface caused by its multi-scale structure.

Reinforcement of cellular materials with short fibres: Application to a bio-based cork multi-scale foam

“…Fig. 1(a) shows the two resulting directions: directions in the (Oxy) plane are called in-plane directions (IP) and (Oz) direction is called out-of-plane direction (OP) [20]. Afterwards the cross-linking was made under compression in an autoclave.…”

“…After this the bead scale has millimetric lengths. Beads can be defined by orientation, volume and shape descriptors [20]. This scale shows several porosities between beads.…”

“…This cell scale is characterised by micrometric lengths. Each bead has a specific cellular orientation [20]. Cork cells have variable dimensions [22] but also variable chemical compositions [23].…”

Novel hyperelastic models for large volumetric deformations

“…[13,17]), and cork (e.g. [62,5,63,47,5]). As seen in Section 4.2, Formulation 2 features the tan function creating a vertical sigmoid shape for the hydrostatic stress.…”

Thin-Rib and High Aspect Ratio Non-Stochastic Scaffolds by Vacuum Assisted Investment Casting

“…Cellular structures, in the form of composite materials, are a classic route to obtain high values of static and dynamic specific mechanical properties [1,2]. This characteristic has always been advantageous in many fields and applications, from diverse areas such as packaging, the transportation industry (e.g., railway [3][4][5] and aeronautic [6][7][8]), and medical implants [9][10][11]. This class of materials, when using a metallic matrix, are classically manufactured by foam blowing agents/gas injection [12][13][14][15][16][17] and casting with space holders with leachable [18][19][20][21][22] or non-leachable [23][24][25] particles.…”