Simulation Based Optimization of Sequential Vacuum Infusion with Controlled Post-Infusion Stage for Thin-Walled Composite Parts Forming

The article presents an approach and method for numerically solving the forward problem of modeling vacuum-infusion molding of thin-walled composite structures with the ability to control the external pressure applied to the preform, the pressure in the vacuum port and temperature to optimize the process. Its objectives are the fiber volume fraction level, the uniformity of its distribution in the preform and the thickness of its walls, the filling of the preform with resin, the duration of the process until completion and unproductive resin waste. Using the examples of three different temperatures, a method for assigning rational moments for increasing and stabilizing controlled pressures is presented, taking into account the rate of filling the preform with resin, depending on its shape, dimensions, permeability, compressibility and rheological state of the thermosetting binder. It is shown that the correct choice of controlled parameters ensures the maximum achievable level, uniformity of reinforcement and, consequently, the best strength characteristics of the molded structure, reduces the variation in the wall thickness of the structure by 10 or more times while achieving acceptable economic indicators of the process.