MODELING OF DISTRIBUTION MEDIA AND VACUUM BAG PROPERTIES ON PERMEABILITY VARIATIONS DURING VACUUM ASSISTED RESIN TRANSFER MOLDING (VARTM)

摘要

This paper investigates the deformation of the vacuum film into the distribution media, its effect on the change of the unit cell porosity and ultimately the reduction of permeability of the overall system in a Vacuum Assisted Resin Transfer Molding (VARTM) process. Experimental results have shown the obvious effects of the vacuum bagging penetration into the distribution media on permeability; however, there is no analytical model to explicitly characterize this phenomenon. In this paper, we proposed an analytical model to capture the vacuum film penetration into the distribution media based on an energy approach for the first time, and then we connect this analytical model with Carman-Kozeny equation to predict the permeability variations in terms of the parameters of plastic vacuum bag and distribution media. Design curves are obtained in parametric studies to predict the permeability reduction as a function of bag modulus and thickness, and distribution media geometry. These reduction factors can be used in flow simulations to accurately predict the resin filling time for a wide variety of distribution media/flexible bag systems. Simulation results are compatible with observations from the preliminary experiment results.