Analysis of Transversal Permeability for Different Types of Glass Fiber Reinforcement

Abstract

In some of the new processes to produce elements in composite materials, the innovation is due to the fact that the resin flow is perpendicular to the plane of the reinforcement during the impregnation. So a very important parameter is the transversal permeability of the reinforcing materials used in these processes. In fact for a high value of this parameter it is possible to increase the product quality and to reduce the process time. In this work, using Darcy's law and a particular permeameter, the transversal permeability of preforms constituted by fabric and mat layers of fiber glass has been valued for different injection pressures. In particular, the permeability of two types of preform, consisting respectively of only mat layers and of only fabric layers, have been determined by tests and calculated by Kozeny–Carman equation. The research has been also focalised on the evaluation of the permeability of preforms constituted by a mix of the two different types of reinforcement. Furthermore an analytical model has been studied to calculate the permeability of preforms consisting of layers of different reinforcement types, starting from the permeability data characterizing the single reinforcement type and determined by the tests or by Kozeny–Carman equation.