ANALYSIS OF COMPOSITE MOLDING USING THE HOMOGENIZATION METHOD

In this paper, we present an application of the homogenization method to the analysis of Resin Transfer Molding (RTM) and Structural Reactio n Injection Molding (SRIM). RTM and SRIM are relatively new molding pr ocesses for manufacturing continuous fiber reinforced polymer composit es. First, the mold flow is analyzed. In the molding process, the resi n experiences significant temperature changes as it fills the mold and forms a free boundary with air as it pushes out the air. In addition, the flow domain is the mold cavity packed with fiber preform, which i s a porous medium. Here, the homogenization method is used to model th e non-isothermal flow through porous media with free boundaries. A com puter program is developed which is capable of simulating a three-dime nsional mold how using the finite element approximation, An example is provided for a three-dimensional part. Then, an analysis of the resid ual stress developed in the curing stage is given, The curing stage st arts when the mold is completely filled and it involves chemical react ion and large temperature variation. In curing, the resin part undergo es larger volume shrinkage than the fiber part, and the residual stres ses are developed due to this volume mismatch. In some cases, these st resses are large enough to cause micro-cracking and to exhaust the str ength of the material. Here, a brief discussion of the application of the homogenization method to a residual stress analysis is given and o ne example is provided.