Numerical simulation of three-dimensional flow and analysis of filling process in compression resin transfer moulding

Abstract

In compression resin transfer moulding (CRTM), resin flows inside a mould filled with fibrous reinforcement as a result of resin injection and mould compression. This process facilitates the resin flow through the fibrous reinforcement particularly for high fiber content parts. This paper presents the numerical simulation of filling process of CRTM in full three-dimensional domain. A mathematical model of three-dimensional resin flow inside the CRTM mould is presented. An effective elastic modulus is introduced for multi-layer preforms connecting the mould closing speed to deformation rate of individual layers. Control volume/finite element method (CV/FEM) is used and the numerical algorithm developed to progress the flow front is based on a quasi-steady state approach, previously employed for resin transfer moulding (RTM), which is here modified for a deformable medium. Element characteristic height (ECH) and element characteristic surface area (ECSA) are introduced to take into account irregular elements in the simulation which are often observed in complex mould cavity. The numerical algorithm presented is coded and the resulting computer code is used to predict the necessary filling parameters such as flow progression, pressure distribution and mould clamping force. The validity of the numerical algorithm is verified by comparison with analytical solutions for simple moulds. Computer code developed is also used to analyse the CRTM process with different filling modes by providing various numerical examples. The results show the effectiveness of the numerical simulation in predicting the CRTM process.