Modeling strategies for fabrics unit cell geometryapplication to permeability simulations.

Numerical approaches at the elementary cell level represent a promising method to determine fabrics mechanical properties and permeability for example. But, these simulations generate lots of difficulties linked to the multi-scale constitution of the fabric and the large strains. A key point for meso 3D finite element simulation is the necessity to have an accurate 3D geometry of the fabric cell. The goal of this paper is to present an efficient strategy to obtain a consistent geometry of complex interlock unit cells. It is based on the commercial CAD software CATIA V5 and a new iterative algorithm. It enables to ensure both accuracy and consistency, i.e. contacts between yarns of the two networks are well described (no voids or interpenetration). Since complex fabrics are concerned, the iterative approach is dedicated to enable the user to get a consistent model using a various number of parameters depending on the fabric structure, the number of available data and the accuracy needed.