Vakum destekli reçine transfer kalıplama yönteminin dolum sonrası aşamasının sonlu eleman yöntemi ve malzeme karakterizasyon verileri kullanarak modellenmesi

Large composite parts are produced using Vacuum Assisted Resin Transfer Molding (VARTM) process; however, the major challenge in VARTM is to fill the mold completely with acceptable dimensional tolerances in the part. Simulation codes based on Darcy law are commonly used for flow modeling in Resin Transfer Molding (RTM) in which the thickness and permeability are fixed, i.e., do not vary with time. However, both thickness and permeability vary spatially and with time in VARTM due to the flexible vacuum bag used as the upper mold part. VARTM simulation codes should be incorporated with compaction models by coupling flow and fiber compaction. This also allows the simulation of post-filling stage of VARTM, where control actions are performed to exit the excess resin and minimize the variation in the part thickness.The present study models the post-filling stage of VARTM using experimental material characterization data for permeability and compaction. Continuity equation is solved using Finite Element Method (FEM) with triangular elements. The coupled distributions of pressure, thickness and permeability are calculated at the end of complete mold filling by using an iterative scheme. The solution is validated with several case studies such as single inlet single exit boundary conditions resulting in a 1D flow, and inlet/exit combinations resulting in 2D flow. Global mass conservation is used for validating the solution algorithm by comparing inlet and exit flow rates.Post-filling stage following a boundary condition update is simulated by starting from the simulated results of the end-of-mold-filling stage; and then applying the change in the boundary condition. The coupled distributions of pressure, thickness and permeability are calculated by using an explicit Eularian time integration; and the stability of algorithm is ensured by modifying the time step size.Modeling of mold-filling and verifying the simulations with experiments remain as future work.