Micro-Meso Draping Modeling of Non-Crimp Fabrics

Composite materials with textile reinforcements are showing rapid growth of integration in aerospace, automotive, sport and other industrial sectors. Especially non-crimp fabrics (NCF) are widely spread because of their high drapeability and good in-plane mechanical properties in main fibre directions. For prediction of mechanical response of composite parts in particular with high curvature it is important to consider the local orientations and gaps in textile structures obtained after draping. Draping simulations are performed on meso-scale structure for this reason. This requires both the geometrical and mechanical properties of the textile components. In the present work high nonlinear mechanical behaviour of textile tows is obtained from micro-scale modelling where filaments are represented as beams with friction contact between them. These simulations were performed for transverse compression, torsion and bending cases and compared with experiments. Obtained mechanical properties are implemented in a new material model using the UMAT interface. Then representative volume elements (RVE) of the textile structure needs to be created without interpenetrations. The detail level of RVE depends on further simulation application. In the present work a new method for generation of textile RVEs with consideration of geometrical parameters and local volume fractions of textile components is proposed and compared with micro cut images of real structure of leno-woven NCF for different detail levels. Results of draping simulations are validated with experiments on a drapeability tester called DRAPETEST lately brought onto the market by Textechno. These results for UD leno-woven glass NCFs are showing good agreement. Calculations of mechanical properties based on mesh superposition technique implemented in LS-Dyna are performed and compared with experimental results.