Accounting for the variability in 3D interlock fabric permeability through fluid flow simulations
Résumé
Variability of intra-yarn permeability within 3D interlock can have an effect on fabric’s permeabil-ity.
This has to be predicted by modelisation to better understand Resin Transfer Moulding (RTM) processes
involved in composite parts. To do so, numerical simulations of a dual-scale flow around and within the
carbon yarns are carried out, with an incompressible fluid flow and a newtonian fluid behaviour.
3D interlock reinforcements are performed by modeling yarns at sub-mesoscale. The yarn deformations
are computed with an enriched kinematics beam model and a contact-friction algorithm [1]. This kind
of modeling provides an intra-yarn fiber volume fraction (FVF) field and thus an intra-yarn permeability
distribution in whole over the unit cell. Then, the geometry is meshed using a robust conformal
adaptative technique based on a voxel representation [2]. Finally, a fluid flow simulation is performed
with a monolithic approach by using the ASGS (Algebraic Sub-Grid Scale) stabilization of Stokes-
Darcy coupled problem with a mixed velocity-pressure formulation [3]. Moreover, the transverse
isotropic permeability tensor of every intra-yarn region is computed in local coordinate system, defined
by the local orientation of the yarn path. The velocity and pressure fields are then upscaled through the
3D generalized Darcy law to compute macroscopic permeability.
Darcy’s permeability of yarns depends on the FVF field, while the inter-yarn pore morphology is
described by the Stokes equation. This approach, from a previous work [3], showed that the permeability
of the unit cell reaches an asymptotic value when the yarns become almost impermeable. However,
since the actual intra-yarn permeability is not constant, the effect of an higher value isotropic intra-yarn
permeability distribution onto the global fabric permeability will be shown in first approach. In a second
part, an anisotropic intra-yarn permeability tensor is introduced to quantify the effect on the variability
of the global fabric permeability. Both studies are carried out at different compaction steps in order to
determine the fabric permeability as a function of the global FVF. Finally, this work focuses on unsteady
dual-scale fluid flow simulations which are strongly affected by capillary phenomena [4].
References
[1] Durville et al. Determining the initial configuration and characterizing the mechanical properties of
3d angle-interlock fabrics using finite element simulation. International Journal of Solids and
Structures, 154:97–103, 2018.
[2] Alain Rassineux. Robust conformal adaptive meshing of complex textile composites unit cells.
Composite Structures, 279:114740, 2022.
[3] Geoffre et al. Influence of intra-yarn flows on whole 3d woven fabric numerical permeability: from
stokes to stokes-darcy simulations. International Journal of Multiphase Flow, 129:103349, 2020.
[4] Monica Francesca Pucci et al. Capillary wicking in a fibrous reinforcement – orthotropic issues to
determine the capillary pressure components. Composites Part A: Applied Science and Manufacturing,
77:133–141, 2015.