Elastic Properties and Compressive Mechanical Behaviour of Closed-Cell Porous Materials: Effect of Microstructural Morphology

This paper studies the effect of different combinations of morphological parameters of porous closed-cell materials on their elastic properties and mechanical behaviour. Three-dimensional representative volumes of porous media with different polyhedral void shapes are investigated, considering variation of statistical realisations of morphological features, such as shape, size and distribution of pores. Description of morphology of each investigated representative volume is formalized using second- and fourth-order correlation functions. The effective properties of representative volumes are calculated with finite-element analysis. Additionally, samples of the studied models were additively manufactured with polystyrene, using fused filament fabrication (FFF/FDM) 3D-printing technique, and subjected to compression. Experimental results for elastic mechanical properties and distributions of strain fields on the surface of the samples, obtained with micro-DIC (digital image correlation), are compared with results of numerical finite-element computations. This is accompanied by analysis of internal-stress distributions to assess the mechanical state of the structures. Patterns and trends observed in mechanical responses of porous materials depending on their different morphological parameters are outlined and discussed.