Computer modelling of cellular structures under uniaxial loading

For structures with uniform cell size, wall thickness, and shape, the fundamental question arises whether the same volume of cell wall material has the same effect when arranged as many small cells or as fewer large cells. A combination of finite element modelling (FEM) and experimental work was conducted to investigate the effect of the number of cells for a fixed volume of nonlinear hyperelastic material subject to large uniaxial tension. Three different structural geometries were analysed using FEM, with all models created within the FEBio software suite. For all structures analysed, the computer results show that the stiffness of the cell walls increases as the number of cells increases while the total volume of solid material is fixed, suggesting that the stiffness of the overall structure also increases. Experimentally, digital image correlation (DIC) was employed to investigate the behaviour of silicone structures of neo-Hookean material under tensile loading. This allowed displacement and strain maps to be created over the surface of the specimen whilst observing also the mechanical behaviour of the overall structure. The experimental results were compared to the FEM results to validate the computer models and to show the influence of the local finite deformation effects in the cell walls on the global mechanical performance of the structures