Manufacturing routes of vacuum assisted resin infusion: Numerical investigation

Abstract

The vacuum assisted resin infusion (VARI) process is a cost-effective technique for manufacturing lightweight large complex composite components. It belongs to the liquid composite molding (LCM) family. In this process, a fibrous preform is placed into a mold cavity, and covered by a vacuum bag, then a sealant tape is used to adhere it to the mold in order to avoid air-resin leakage. A vacuum pump is used to evacuate the air from the closed cavity which leads to compact the fabric preform. The inlet gate is opened and resin impregnates the preform under atmospheric pressure. Based on the tripping of compaction and resin infusion phases, several manufacturing routes manifest and have influence on the process time, resin pressure distribution and preform thickness uniformity. In this paper, a numerical simulation, based on the finite difference method, is conducted to investigate the effect of four major manufacturing routes of VARI process on the aforementioned parameters. The obtained results reveal that the merging of the air vacuuming and resin infusion phases has no mentioned effect on the reduction of the process time. While, the fourth manufacturing route, where the resin injection precedes vacuuming phase, is the best practice of vacuum assisted resin infusion process. In its optimum scenario, this route can reduce the process time with 19.9% as compared to the optimum scenario of the first manufacturing route.

Simulation Study and Optimization Strategies for Vacuum Infusion of GFRP Hoses Based on Resin Time-Viscosity Variables

“…The polynomial fitting method gave the best fitting result in this study and was therefore selected as the best method to use (as demonstrated by the red solid line in Figure 4). The expression for this method is shown in Equation (8).…”

“…Vacuum-assisted resin transfer molding (VARTM) utilizes negative pressure from a vacuum to facilitate resin impregnation into fiber fabrics [8]. In comparison to conventional resin transfer molding (RTM), the vacuum properties in the pre-filled region of VARTM enhance the ratio of fiber to resin after impregnation, effectively reducing porosity and increasing the strength of the product after curing [9].…”

Effects of vacuum infusion configuration on homogeneity of glass fiber reinforced polymer composites for automotive components

“…VARIM techniques are applied by stacking the layers on the mold until the desired thickness is reached and after that vacuum is applied to remove air inside the mold cavity. The matrix material (liquid resin) is introduced to the preform via vacuum force and the excess resin is removed from the layers [6]. With this technique, it is possible to fabricate composite materials with minimum resin usage and no air cavities in the material structure that deteriorates the mechanical properties.…”

A Constructal-Theory-Based Methodology to Determine the Configuration of Empty Channels Used in the Resin Impregnation of a Square Porous Plate

“…The deployment of numerical approaches for the prediction of LCM processes has been widely explored in various studies [1,[9][10][11][12][13][14][15][16][17][18][19]. For example, Pierce et al [12] developed a computational model to estimate resin infusion considering the permeability heterogeneities along the preform and tissue deformation.…”

“…The Navier-Stokes equations are solved in the region of free flow, whereas the tracking of the flow front of the resin is modeled using the Cahn-Hilliard equation. Ouezgan et al [19] performed a numerical investigation to identify strategies for manufacturing routes that improve parameters such as resin pressure distribution and infusion time. The authors verified that the strategy of resin injection preceding the vacuum step reduced the infusion time in the fibrous medium.…”