Simulation of the Complete Resin Infusion Process

Abstract

Resin Infusion (a.k.a. VARTM) is one of the Liquid Composite Moulding processes, for which liquid resin is drawn into dry fibre reinforcement. Resin Infusion is a closed mould process in which half of the mould is formed by a flexible vacuum bag. Significant cavity thickness changes occur during processing, due to the flexibility of the vacuum bag and the complex stress balance within the laminate. While the magnitude of thickness change is often small, the influence is significant on reinforcement fibre volume fraction. Dynamic changes in permeability during mould filling and post-filling have the potential to significantly affect the process. To simulate this behaviour, it is important to accurately model the compaction and relaxation of reinforcement in the dry and wet state. A series of tests have been completed to determine the compaction behaviour of an isotropic glass fibre mat. From these tests several non-linear elastic compaction models have been determined, and applied within a new Resin Infusion simulation. The process simulation, which addresses the pre-filling, filling and post-filling stages, is compared to an experiment employing a full field cavity thickness measurement apparatus, as well as measurement of resin pressure at three discrete points within the laminate.