ANALYTICAL AND NUMERICAL STUDIES INTO THEVACUUM INFUSION PROCESS: IN-PLANE FLOW INCOMPRESSIBLE POROUS MEDIA

摘要

Vacuum infusion (VI) and Resin Transfer Moulding (RTM) are among the most significant and widely used Liquid Composite Manufacturing processes. Both rely on resin infusion of dry reinforcement materials inside closed moulds but are fundamentally different in terms of mould construction and fluid pressures used. Unlike RTM, vacuum infusion (also known with slight variations as VARTM, SCRIMP?, VM, RIFT, etc.), is commonly used to produce large components and is acknowledged for its relative low cost and superior quality when compared with traditional open mould techniques. Furthermore, the use of a flexible polymeric film in VI has profound implications in the fluid mechanics of the process. This flexibility of the vacuum bag is responsible for a fluid pressure dependent compaction of the reinforcement and consequently local time dependent thickness and permeability. VI has been the object of intensive study in the past decade; nonetheless a number of problems still need to be addressed such as further analytical developments of the flow model, identification of relevant parameters, and sensitivity studies. This work?s main contribution is then to explore these issues and reveal the implication of different fibre architectures, compaction and permeability models and parameters on flow and mould filling. The parametric studies are also focused on the modelling of natural permeability variations for control oriented applications of this model.