Three-dimensional modeling of the advanced grid stiffened structures in the co-curing process

Advanced grid stiffened (AGS) structures are made of carbon fiber reinforced polymer composites, which consists of a main panel with isogrid stiffeners. During the co-curing process, the autoclave pressure will compress the surface of the AGS structure to repel excess resin and voids. Because of the thermal expansion of the rubber, the rubber mold can provide the necessary lateral compacting forces on the rib stiffeners. This study constructs a three dimensional numerical model to simulate the consolidation behavior between the skin prepreg and the silicone rubber under a preset temperature profile. The model could provide the thickness distribution and fiber volume fraction of the AGS after the co-curing process. The consolidation pressure of the silicone rubber is proportional to its CTE and the curing temperature. With the numerical model, a suitable type of silicone rubber can be selected for the tooling.