I need your help regarding FEM modeling of textile. I am dealing with fabric made of PET (Polyethylene terephthalate). The structure of this fabric is shown on the attached picture. The textile is placed in a sandwich between two rubber or PTFE layers. Its purpose is structural reinforcement of these parts. However this textile layer is not embedded or otherwise tied to outer layers. Therefore in my opinion I cant apply homogenization approach as used in reinforced materials. The other problem is that I need to know what is happening in this layer, so the layer has to be discretized as well.
For this simulation I am using Abaqus. My approach is to discretize the fabric layer through membrane elements, since textile has no bending stiffness. The problem is how to model or rather how to calibrate this model. As you can see from the attached picture, the textile consists of thicker yarns and thinner warps (or vice versa 🙂 ), so that the orthotropic elasticity (or hyperelasticity, but lets leave this aside for a moment) seems like a natural approach. In this case I would need to measure the corresponding moduli of elasticity and poisson ratios, which I have no idea how to do. The contact friction between yarns and warps can affect the mechanical behavior of textile, in my opinion significantly. Any idea how to tackle this problem? Are there some good references you can recommend me on modeling of textile?
All constitutive models for textiles I have found relate the deformation of fabric (i.e. extension) to force acting on fabric. If I have noticed this well the dimensions of threads are not important. Any idea how can I translate this to stresses? How to represent the porosity then?