During typical compression resin transfer molding (CRTM), resin is first injected into a gap between the mold and fiber preform, and the preform is then impregnated in the out-of-plane direction. CRTM thus has an advantage of reduced molding time because of the short impregnation distance. This study predicts resin flow during CRTM of composite structures by performing a resin impregnation simulation using the finite-element method. In the case of the CRTM of a thin curved plate, resin penetrated the preform beneath the gate by the resin pressure, when the injection of the resin into the gap was finished. Reduction of the molding time cannot be achieved in such a case, because impregnation proceeds over a long distance in the in-plane directions. Furthermore, in CRTM with multiple gates and multi-axial compression for an L-shaped component connecting two plates, impregnation was concentrated near the connecting part, and a non-impregnated area remained after finishing compression of the preform. The molding time by CRTM was always longer than that of vacuum-assisted resin transfer molding even at an increased compression speed. These results indicated that optimization of the molding conditions is necessary to achieve the benefits of CRTM.
