Dipl.-Math. Bart Verleye (K.U.-Leuven), Prof. Dr. Dirk Roose (K.U.-Leuven), Prof. Dr. Stepan Lomov (K.U.-Leuven)

The calculation of permeability presumes a thorough characterisation of the textile reinforcement, which is provided by the WiseTex software [3] developed at the Katholieke Universiteit Leuven in Belgium. In cooperation with the Composite Materials and the Scientific Computing Research Group in Leuven we are developing a new module for their software package FlowTex for the computation of the permeability of textile reinforcements [1]. This module is based on the freely available flow solver NaSt3DGPF, a CFD package which is developed at the Institute of Numerical Simulation. Results of the permeability predictions can be compared to results obtained by a Lattice Boltzmann model [2] and can be validated by experimental data.

Textile composites are hierarchically structured materials. Therefore, a model for fluid flow in textiles should be able to account for porosity on several length scales of the material. That means, if we want to calculate the permeability on the scale of the composite unit cell (inter-yarn flow), we should be able to decide if the porosity of the yarns is to be taken into consideration (intra-yarn flow).

Hierarchy of Structure and Models of a Textile Composite | ||

Structure | Elements | Fluid Flow Parameters and Equations |
---|---|---|

Yarn (tow) | Fibres | Calculation of permeability if yarns are porous |

Fabric (woven, knitted) | Yarns | |

Composite unit cell | Fabric | Flow Modelling by Navier-Stokes or Navier-Stokes-Brinkman |

Calculation of the permeability tensor by Darcy's law | ||

Composite part | Deformed unit cells | Flow of the resin |

where denotes the permeability of the yarn, is the fluid viscosity and the fluid density . On the other hand, if intra-yarn porosity is neglected, yarns are merely treated as solid obstacles for the standard Navier-Stokes equations.

where and are the volume averaged fluid velocity and pressure.

**Example 2: Monofilament Fabric Natte 2115**

KULeuven: Scientific Computing Research Group

[1] | Verleye B., Klitz M., Croce R., Roose D., Lomov S., Verpoest I., Computation of permeability of textile reinforcements. 17th IMACS World Congress, 2005. |

[2] | Belov E.B., Lomov S.V., Verpoest I., Peters T., Roose D., Parnas R.S., Hoes K., Sol H., Modelling of permeability of textile reinforcements: lattice Boltzmann method. Composites Science and Technology 2004; 64(7-8):1069-80. |

[3] | Lomov S.V., Huysmans G., Luo Y., Parnas R.S., Prodromou A., Verpoest I., Phelan F.R., Textile composites: modelling strategies. Composites Part A 2001: 32(10):1379-94. |

[4] | Griebel M., Dornseifer T., Neunhoeffer T., Numerical Simulation in Fluid Dynamics, a Practical Introduction. SIAM, Philadelphia, 1998. |

- Development of CFD Code NaSt3DGP