장섬유강화 복합재료 구조물의 기계적 접합을 위한 스테인레스 강 인서트 설계

초록

Long Fiber-reinforced composites have advantages of excellent production efficiency and formability of complex shapes compared to conventional continuous fiber reinforced composite materials. However, if we need to make complicated composite shapes or to assemble parts made of different materials, a variety of joining methods are needed. In general, long fiber prepreg sheet (LFPS) contains mold release agent to facilitate demolding after thermoforming. Therefore, mechanical fastening is required in addition to the adhesive bonding to get proper joining strength. In this study, we proposed a stainless steel insert for co-cure bonding which cures LFPS and bonds the stainless steel insert through thermoforming process. The wing of the insert which is spread during the thermoforming process induces adhesion and mechanical wedging effect and serves as a hook to resist the pulling force. The burn-out method was used to confirm the unfolded state of the stainless steel insert wings inserted into the composite material. The static pull-out test was performed to quantitatively evaluate the joining strength. From these experimental results, the condition which guarantees the most appropriate joining strength was derived.

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