Permeability Tests of Fiber Fabrics in the Vacuum Assisted Resin Transfer Molding Process

A special device is designed to measure the in-plane and through-thickness permeability of a preform for the vacuum assisted resin transfer molding (VARTM) process. The device is composed of pressure control module, aluminum experimental platform, thickness test module, and pressure test module, which is controlled by a computer. Two kinds of experiments were conducted for carbon fiber noncrimp biaxial fabrics to verify the reliability of the new device based on constant pressure injection. The two experiments are composed of: (1) testing of in-plane permeability for 1, 5, 10 and 20 layers with the method of the line injection by comparing the two conventional methods; (2) testing of the through-thickness permeability for the laminate denoted as [±45] ₂₀ with the central injection method. The results show: (1) the in-plane permeability decrease with the increase of layer number and the permeability for 20 layers is only 62 % of the one layer; (2) the in-plane permeability is an order of magnitude greater than through-thickness permeability based on experimental results of laminate denoted as [±45] ₂₀. A good agreement obtained between the device and two comparison methods proves the validity of the device.