The role of geometrical disorder on swelling anisotropy of cellular solids

The anisotropic swelling behavior of two-dimensional cellular solids is investigated using computational upscaling of periodic honeycombs and compared with direct finite element simulations of real cellular structure of wood as a complex cellular material. In both models, the anisotropy of the cell wall material has been taken into account. The real structure model is used for inverse determination of swelling coefficients of the wood cell wall by comparing the simulation results to free swelling experimental data. The obtained results reveal that the cell walls swell to a much less extent along the cell wall than in the thickness direction. A systematic study is carried out to investigate the influence of geometrical disorder on swelling properties. It is found that periodic symmetric honeycombs provide the upper bound for anisotropic swelling ratio, while disorder in arrangement of the cellular structure reduces the swelling anisotropy.

► The macroscopic swelling behavior of two-dimensional cellular solids is investigated.
► Symmetric and disordered honeycombs and real structure of wood are simulated with finite element.
► The influence of geometrical disorder on swelling anisotropy is studied.
► Periodic symmetric honeycombs show the largest anisotropic swelling ratio.
► More disorder in honeycomb structure leads to less swelling anisotropy.