Compression behavior and in-plane permeability of 3D textiles via FEM and CFD simulation

Permeability measurement of easily deformable porous materials saturated with liquids represents a costly and time-consuming process, usually performed with complex experimental devices. This study proposes an alternative approach for evaluating the in-plane permeability of 3D warp-knitted spacer fabrics under compression. A 3D model was reconstructed from scanned images, and its behavior was analyzed using the finite-element method. The resulting deformed shapes of the representative cell were used in computational fluid dynamics simulation to assess the permeability across a wide compression range, approaching the densification phase. The permeability was determined from Darcy’s law at reduced flow speeds, whereas higher flow speeds were analyzed using the quadratic extension (Forchheimer) of the linear regime. Finally, simulation results at various compression ratios showed good agreement with experimental measurements, thus validating the numerical approach.