Resin infusion of sandwich structures - Core/skin interactions and void formation

This paper presents results of experimental and modelling work exploring aspects of fibre, core and resin interaction during the infusion process. In particular we observe the nature of regions of flow front convergence in areas containing various types of core, such as wood, sealed wood and closed cell foam. Data on comparative resin absorption for the various cores are presented. It is found that sealing porous core materials such as balsa does not prevent the absorption of significant quantities of resin. More importantly, completely impervious cores are unable to absorb either air or resin. The result of this is that air trapped during flow front convergence causes a higher degree of void content in the skin laminate, compared to more porous core materials. These phenomena appear to have attracted little research attention to date, and provide significant challenges for both experimentation and process simulation.