Process Mechanisms and Material Properties for Advanced VARI Flow Simulation

Vacuum-Assisted Resin Infusion (VARI) is a member of Liquid Composite Moulding (LCM), a family of process technologies for manufacturing a wide variety of structures from fiber-reinforced polymer composites. While simple in its working steps, VARI is surprisingly complex in terms of process mechanisms. As a result of a semi-rigid mould (single-sided, flexible vacuum bag), the pressure gradient changes during the infusion process. As a result, the preform thickness changes with time and spatial location, which directly impacts its porosity and permeability. Moreover, the material setup typically contains auxiliary materials such as single layers of peel ply and flow distribution media next to the fibrous reinforcement. Thus, an inhomogeneous material setup is obtained which leads to a combination of in-plane and out-of-plane flow effects. The purpose of this thesis is to provide a comprehensive data basis required as input for advanced VARI process simulation. In particular, (i) ply thickness and compressibility, (ii) in-plane permeability and (iii) flow progress in VARI experiments will be conducted by the candidate. Two different glass fiber based fabrics (a woven and a non-crimp fabric) as well as peel ply and flow distribution media, typically used as VARI consumables, will be characterized. Moreover, the data obtained from the experimental work will be used as input data for VARI flow simulations. The flow progress tracked in the experiments will be compared with the predictions from VARI flow simulation runs.