Abstract
Resin transfer molding (RTM) is a manufacturing method of composite materials, which have been widely used in many areas including aeronautic, automotive industries, etc. In RTM, permeability of fiber reinforcement varies with its geometric formation and affects the property of resin flow, which influences the final product quality. Therefore, effective online estimation is crucial to achieve good process control and satisfactory quality product. In this work, a method for online measuring local permeability is proposed. It can deal with variation in local permeability within preform caused by irregular arrangement of fibers among different regions. This study is divided into two stages. In the first stage, flow visualization was realized and all hardware was integrated to acquire information in resin filling period. In the second stage, local pressure and flow front location were substituted into the Darcy's law, thus making online calculation of local permeability feasible. At the end of this study, we used the proposed methods in a trial RTM test and compared their results to those from the reference method to confirm their effectiveness.