Homogenization of flow in inflatable periodic structures with nonlinear effects

The paper presents a new type of weakly nonlinear two-scale model of inflatable periodic poroelastic structures saturated by Newtonian fluids. The periodic microstructures incorporate fluid inclusions connected to the fluid channels by admission and ejection valves represented by a 0D model. This induces a nonlinearity in the macroscopic Biot-type model, whereby the Darcy flow model governs the fluid transport due to the channels. Moreover, the fluid channels consist of compartments separated by semipermeable membranes inducing the pressure discontinuity. The homogenized model is derived under the small deformation assumption, however the equilibrium is considered in the Eulerian frame. Deformation-dependent homogenized coefficients of the incremental poroelasticity constitutive law and the permeability are approximated using the sensitivity analysis, to avoid coupled two-scale iterations. Numerical simulations illustrate the inflation process over time. Example of a bi-material cantilever demonstrates the inflation induced bending. The proposed two-scale model is intended to provide a computational tool for designing of porous metamaterials for fluid transport, or shape morphing with various potential applications.