Thermal Behaviors of the Resin and Mold in the Process of Resin Transfer Molding

The manufacture of polymer composites through the process of the resin transfer molding (RTM) involves the impregnation of the reactive polymer resin into a mold with preplaced fibrous reinforcements. Determination of RTM processing conditions requires the understanding of various parameters, such as material properties, mold geometry, and mold filling conditions. Modeling of the entire RTM process provides a tool for analyzing the relationship of the important parameters. This study developed a nonisothermal simulation model to simulate the thermal behaviors of the resin and mold during the resin transfer molding process based on the control volume finite element method. The model will be able to simulate the thermal and chemical changes of the resin and the thermal variations of the mold during the filling and curing stages. Thermal effect of the epoxy mold was shown to have large influence on the temperature distribution and curing process of the resin. Results of some numerical studies in RTM show the applications of the proposed model.

Gate Location Optimization in Liquid Composite Molding Using Genetic Algorithms

Manufacture of polymer composites using the process of liquid composite molding involves injection of a reactive resin into a closed mold with preplaced fibrous reinforcements. There are many studies that address the computer simulations for mold filling. The simulation programs provide the simulated mold filling results for a known gate location. However, they do not discuss the method for determination of the gate locations, which is one of the important issues in the total mold design. In this paper, a gate location optimization method was developed based on minimization of the mold filling pressure, uneven filling pattern, and temperature difference during the mold filling process. A genetic algorithm was used to search the optimal gate location. This method, in general, has a better chance to locate the near global optimum than the gradient based search method, especially in the problems with multiple variables and a large search space.