In the hybrid molding of CFRTP, short or long fiber-reinforced thermoplastics, which compose rib and complicated structures, are injected on top of the continuous fiber-reinforced thermoplastics that are used for the outer shell material. In previous studies, it has been reported that fractures often occur at the interface between short or long fiber-reinforced thermoplastics of the rib structures and the continuous fiber-reinforced thermoplastic laminate of the outer shell structure. By applying cut prepreg having high formability to flow into their interface, improvement of the bond strength of the interface at the rib root portion can be expected. In this study, the press and injection hybrid molding was conducted by supplying cut prepregs to the continuous fiber-reinforced thermoplastic laminate of the outer shell structure, and T-shape specimens extracted from the rib root portion were evaluated by the tensile tests to clarify the effect of the penetration height of cut prepregs to the rib structures on the bond strength of the interface. Higher interfacial strength can be obtained when the reinforced fibers of the penetrated cut prepregs in the rib were oriented to the vertical direction to the interface.
