Effect of Nesting in Laminates on the Through-Thickness Permeability of Woven Fabrics

The layer nesting phenomenon of multilayer fabric has a great influence on the through-thickness permeability, which is a key parameter for the simulation of the through-thickness LCM (Liquid Composite Moldling) processes. In this paper, based on the analyses of the formation reason and characterization parameters of layer nesting, the geometry models of fabric unit-cells with nesting are established. The through-thickness flow in the unit-cell is analyzed to built the governing equations of the resin flow. The inter-yarn and intra-yarn regions of the unit-cell model are discretized uniformly, then the governing equations of the through-thickness flow are numerically solved based on Adams-Bashforth scheme and Chorin projection method, so the through-thickness flow parameters is obtained and the through-thickness permeability of the fabric with nesting can be predicted. The verification of the above method is implemented by comparisons with the available experimental results. A series of simulation experiments are carried out to investigate the nesting behaviors under different layer shifts, and the effects of nesting on the total thickness and through-thickness permeability of woven fabric are researched in detail.