Simulation of Vacuum Assisted Resin Infusion (VARI) process for the production of composite material parts

Abstract

The Vacuum Assisted Resin Infusion (VARI) is manufacturing process used worldwide to produce composite parts having great diversity of dimensions (from small to very large ones) and geometrical complexity. This manufacturing process is particularly versatile, to produce small series of high performance structural parts. In these cases, the simulations of the VARI process is a very useful tool to define the infusion strategy and to plan and predict the resin flow progress in order to reduce the material waste and manufacturing cycle time and obtaining lighter structures, having lower void fraction and higher fibre content and mechanical performance. The numerical simulation of the VARI process implies the modelling of different complex phenomena, such as flow in porous media, mechanical deformation, heat exchange and chemical reaction. Therefore, a finite element software was used to solve a combination of governing equations based on a combination of pre-defined theoretical assumptions, by considering a moving mesh and appropriated boundary conditions. In this work, results obtained from simulations of VARI process were used to define the best strategy to be applied in the production of composite parts with different geometries, sizes and materials and predict the possibility of defects occur. In order to validate the accuracy of simulations, the numerical results were compared with those experimental ones obtained from the production of different composite parts where the best processing strategies were implemented. After analysing and discussing the theoretical and experimental obtained results, changes were applied to the numerical model to improve simulation accuracy.