Local impregnation behavior and simulation of non-crimp fabric on curved plates in vacuum assisted resin transfer molding

In the resin transfer molding (RTM) process, the existence of curved regions in a mold can significantly affect the resin filling process. To investigate the impregnation behavior in curved regions, a systematic experimental study was performed to detect the influences of bend angles, flow lengths, and preform layers on the resin flow-front progression. The results revealed that curved regions on molds would increase the resin flowing time by 15-30%, and this was attributed to the interaction between preform deformations and the race-tracking effect along the centerline. An analytical methodology was developed to simulate the flow progression on curved molds, where the pressure loss coefficient and overall permeability variations were evaluated. This analytical methodology provides a reliable and concise method for predicting the permeability variations on curved molds, without testing preform mechanical properties or building representative volume elements to model preform deformations.