Resin transfer molding is a widely used composite material manufacturing process that produces high-strength and lightweight parts for various industrial applications. In order to manufacture defect-free parts with consistent material properties, it is important to control process parameters throughout the entire volume of the molded part. Usually a curing schedule includes a pre-warming to the resin viscosity reaches a minimum, further applying of pressure, and finally consolidation of resin at elevated temperature to its full polymerization. To ensure the uniformly state of the composites across the thick-walled products, we propose a model-based approach to the problem of optimal control synthesis using a mathematical model for curing an epoxy-based composite structure with varied thickness. The PDE system linking a kinetic equation with heat transfer equation takes into account an exothermic heat, a phase transition of resin from liquid to gel and further to the solid state, and well describes the cure process which is controlled by independent heat sources. To synthesize the multi-objective optimal control law, we perform the transient analysis of the developed model to calculate the coordinates of Pareto points in the 8-dimensional space of design variables. An efficiency of such approach in the manufacturing applications we demonstrate on example of cured glass-epoxy composite part with a varied thickness.
Ключевые слова: Composite material; Curing process; Optimal control; Kinetic equations; PDEs in connection with control and optimization, Finite element modeling – FEM, Pareto frontier