Manufacturing routes of vacuum assisted resin infusion: Numerical investigation

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.