Injection gate definition for improving the accuracy of liquid composite molding process simulation

Computer simulation has become an efficient and cost-effective toot for the liquid composite molding (LCM) processes, including the RTM, VARTM, and resin infusion, compared to trial-and-error. The purpose of simulation is to accurately reflect the real situation. Since the simulation is predominantly based on the control volume finite element method (CVFEM), the boundary conditions such as gate and vent definition need to be properly defined. In this paper, the errors of the CVFEM based mold filling simulation were analyzed. The error sources were identified as the mesh near gates and vents, and gate definition. By conducting 3-D and 2-D simulation case studies, the influence of the gate definition on the simulation result was studied. Because many composite parts are shells and can be regarded as surfaces, 2-D simulation is favorable because of the better efficiency and simpler pre-processing. For this purpose, a method for mold filling simulation incorporating the gate size effect - the effective gate method (EGM) - was developed. This method was validated through case studies. It shows that the EGM provides an effective and efficient approach to the CVFEM mold filling simulation incorporating the effect of injection gate size.