Abstract:
Liquid Composite Moulding (LCM) process simulations are increasingly used as process design tools to select optimal manufacturing parameters for fibre reinforced polymer (FRP) composite materials. Accurate permeability data of textile preforms is an essential input for these simulations. For maximum accuracy it is desirable to capture both the preform’s permeability and its spatial variation. An automated tool has been developed for generation of permeability predictions for multi-layered unit cells utilising textile modelling techniques. A reinforcing textile is initially scanned and its geometric parameters determined using image analysis techniques. Textile models of a single layer are then created and combined to replicate the stacking step during preform manufacturing. Compaction simulations are applied to these stacks, capturing changes in geometry as well as nesting. Voxel meshes representing the volume of resin around the compacted geometries are then exported. The voxel meshes are automatically cleaned, deleting any floating elements, and the boundary regions defined based on the unit cell size. By executing flow simulations on these meshes, the permeability characteristics of the preform are obtained. The tool has been used to study the effect of preform structure on its permeability, including consideration of the number of layers, stacking sequence and ply shift. The analysis is verified by computing the full three-dimensional permeability, and comparing this to in-plane permeability data obtained experimentally.