Effect of nesting on the compaction behavior of unidirectional fabrics

Based on the analysis on the change of the fiber bundle's cross-section and its constitutive model, compression model of two-layer fabrics was established with different nesting. The model associated fabric thickness with compression load, fabric structure and layer shifting could be used to describe the compressive behavior under any nested state. On this basis, the multilayer fabric compression model was further established. Through the numerical solution of the above model, the compressive response of different layers was predicted. The main conclusions are as follows:The average thickness decreases with the increase of shifting ratio at a given pressure. The distribution of average thickness per layer takes the shape close to a typical distribution at a given pressure and becomes narrow with the increase of the number of layers. When the number of layers is more than 10, the compaction properties of multi-layer fabrics can be described by the mathematical expectation of the thickness of inner layer as a function of external load. The model is in well accordance with the experimental data. The feasibility of the model is verified.