A multi-segment injection line and real-time adaptive, model-based controller for vacuum assisted resin transfer molding

To improve process controllability during VARTM, a new resin injection line was developed. The injection line, which consists of multiple segments each independently operated, allows for the delivery of resin to different locations within the mold. Simulation of different injection line configurations for various mold geometries is studied and validated with laboratory size molds used to demonstrate the potential value and benefits of this approach. Computer-based, closed-loop controller strategies have been designed that use point sensor feedback of resin location within the mold during injection to operate the segmented injection line. In addition to a simple closed-loop control algorithm, an adaptive controller was developed that uses a finite element model to simulate filling characteristics in real time and configure the segmented injection line to minimize dry, unfilled regions within the mold. Simulations and experiments with VARTM molds containing large permeability variations revealed that mold filling was significantly improved with closed-loop control compared to the open-loop response with a conventional injection line.