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

In this paper, the effect of layer shifting on out-of-permeability of 0 degrees/45 degrees alternating multilayer fabrics was studied. Three mathematical models with three extreme structures were developed to predict the out-of-plane permeability, respectively. By segmenting the unit cell into several different zones according to characteristic yarn arrangement, the global permeability was modeled by using a rule of mixture of local permeability. The influences of local permeability of each zone on the global value of unit cell were carefully researched. In addition, experimental measurements of the permeability were carried out to validate the analytical models. And the differences of the results of three extreme structures with respect to fiber volume fraction were also investigated.