Effect of layer shift on the out-of-plane permeability of 0°/90° noncrimp fabrics

Abstract

Layer shift has a great effect on the permeability which is a key parameter in resin transfer molding. In this paper, nine different unit cells were modeled based on the range of layer shift and decomposed into zones of characteristic yarn arrangement, respectively. For each unit cell, a set of equations was derived allowing description of the local permeability of each zone as a function of geometrical yarn parameters. The overall permeability was then modeled as a mixture of permeabilities of different zones with the electrical resistance analogy. Excellent agreement was found between predictions and experiment. Both results indicated that the channel flow had a dominant role in the whole flow through the fabrics. And the permeability values reached maximum when the empty regions were interconnected between upper and lower layers. In addition, the effect of fiber volume fraction on the differences of two extreme cases was also investigated.

Permeability models of 0°/45° alternating multilayer fabrics considering the effect of layer shift

“…As mentioned in Fang et al, 27 there are three extreme structures for 0 /45 alternating multilayer fabrics when layer shifts as shown in Figure 1. The three types are generally referred to as the ''min-min'' structure, the ''min-max'' structure, and the ''max-max'' structure.…”

“…This significant difference has not been paid enough attention to. Fang et al 27 established a permeability model to study the influence of layer shift on the out-of-plane permeability of 0 /45 alternating fabrics, but this model was only applied to ''min-min'' structure. They did not consider the ''min-max'' and ''max-max'' structures, which are the other two extreme lay-up conditions.…”

Numerical and experimental investigation of saturated transverse permeability of 2D woven glass fabrics based on material twins

“…The effect of nesting on transverse permeability of fibrous reinforcements was also investigated in several other studies. Fang et al and Jiang et al proposed theoretical models to predict the transverse permeability of unidirectional and noncrimp fabrics that were compared to experimental results. This analysis showed that layer shifts and nesting have a great effect on the permeability of these two types of fabrics.…”

“…The results show that the stacking sequence plays a significant role on the transverse permeability of engineering fabrics. However, these papers do not give a full picture on the effect of nesting on permeability, because in References , only two plies were tested which is not fully representative of real materials, and in References , only unidirectional fabrics were investigated. The effect of nesting on the transverse permeability of multilayer woven fabrics still needs to be studied.…”

In-Plane Permeability Model of 0°/90° Non-crimp Fabrics in Resin Transfer Molding

“…In our past studies [5], the permeabilities of unidirectional fabrics have been modeled with the electrical resistance analogy. In the reference [6], the out-of-plane permeability of 0°/90° non-crimp fabrics also has been studied with the same method.…”