The driven flow vacuum infusion process: An overview and analytical design

This article describes a novel variant of the vacuum infusion process based on a multifunctional elastomeric reusable vacuum bag. The main innovation of this process is an elastomeric membrane having resin flow channels that can be controlled during the infusion process: they can be activated for the impregnation stage to enhance resin flow and removed during the curing stage to provide a smooth surface finish to the part. In addition, the size of the resin flow channels can be modified during the infusion providing control on the impregnation rate. This article describes the driven flow vacuum infusion (DFVI) process and presents analytical calculations regarding the effect of the geometrical design of the membrane and the processing variables on the porosity, permeability, and volume of resin transported by the flow medium. Preliminary results of unidirectional resin infusion tests comparing the DFVI process to traditional vacuum infusion and SCRIMP are also presented.

An experimental investigation on infusion time and strength of fiber metal laminates made by vacuum infusion process

The vacuum infusion process can be used to fabricate fiber metal laminates with reduced manufacturing time and cost. In this method, the holes in the aluminum layers are created due to the better flow of the resin and to ensure that the fibers are completely impregnated. Created holes can cause problems in using these fiber metal laminates. For example, structural strength is reduced and some parts of the composite layers are exposed to environmental conditions. A proper solution to these problems has been proposed and investigated in this article. If a non-perforated aluminum layer is used as the first layer to be in contact with the mold, this layer becomes the outer layer of the structure made of fiber metal laminates. This non-symmetric fiber metal laminate will still be resistant to moisture and other environmental conditions due to the presence of an intact aluminum layer on the outermost layer, such as conventional fiber metal laminates. This aluminum layer also increases the strength of fiber metal laminates in comparison with fiber metal laminates that its all aluminum layers are perforated. In this paper, the effect of holes diameter of aluminum layers on the resin flow rate (consequently the duration of the fabrication) and the mechanical strength of the structure were investigated. The results showed that holes in the upper and middle layers of aluminum can significantly increase the speed of fabrication, but the presence of the holes causes a slight decrease in the final strength of the sample.

Enhanced Tensile and Wear Properties of CFRP Composites Manufactured Using Vacuum Infusion Process

The properties of a composite are depending on the manufacturing process, fiber and its configuration, epoxy used etc. The present research deals with the tensile and wear behaviour of the composites manufactured using Hand Layup (HL) and Vacuum Infusion Process (VIP) with structural and non-structural epoxy combination. 4-layerd (all the layers are oriented in the longitudinal direction) unidirectional CFRP was manufactured using VIP and those results were compared with the HL made samples. The addition of structural epoxy in the resin mixer have shown a significant effect on its fiber volume fraction, tensile and erosion properties. The effect of vacuum pressure in mould cavity on the tensile strength of the CFRP composite was also studied. The morphologies of the CFRP composites made with VIP and HL were studied with the help of the scanning electron microscopy (SEM). The CFRP composites manufactured through VIP have shown a greater tensile strength but it was poor in wear resistance. The addition of structural adhesive to the resin system enhanced the wear resistance. Hence it made the VIP a recommended process for composite manufacturing where both tensile and wear properties are required.