Graphene nanoplatelets 첨가 및 아라미드 섬유의 적층 구조가 CFRP의 충격 특성과 인장 및 굴곡 물성에 미치는 영향

다국어 초록 (Multilingual Abstract)

Although Carbon Fiber Reinforced Plastic (CFRP) is extensively utilized in high-performance industries due to its superior specific strength and stiffness, its application is often constrained by inherent brittleness and susceptibility to impact loading. To address these limitations, this study investigates a hybrid design approach that combines aramid fiber hybridization with the incorporation of Graphene Nanoplatelets (GNPs). The primary objective is to enhance the impact resistance of CFRPs while simultaneously mitigating the degradation in tensile and flexural properties typically associated with the hybridization of high-toughness fibers.
Hybrid composites were fabricated using carbon and aramid fibers via a vacuum resin infusion process, varying the stacking sequences and GNP concentrations (0.3, 0.6, and 0.9 wt.%). The mechanical and morphological properties of the fabricated composites were comprehensively evaluated using tensile tests, flexural tests, and drop-weight impact tests, complemented by Scanning Electron Microscopy (SEM) and ultrasonic C-scan analyses.
Experimental results identified 0.6 wt.% as the optimal GNP content. Concentrations exceeding this threshold induced particle agglomeration, which acted as stress concentrators and consequently degraded mechanical properties. Among the stacking configurations, the CAC structure (comprising outer carbon layers and inner aramid layers) exhibited the highest impact energy absorption. This superior performance is attributed to the high stiffness of the outer carbon layers, which resist initial impact, and the ductility of the inner aramid layers, which facilitate energy dissipation. While aramid hybridization alone resulted in decreased tensile and flexural properties due to the relatively lower stiffness of aramid fibers and interfacial stress concentrations, the incorporation of 0.6 wt.% GNPs into the CAC structure (CAC 0.6) effectively compensated for these mechanical losses. Consequently, this study demonstrates that reinforcing the CAC hybrid stacking sequence with 0.6 wt.% GNPs is an optimal strategy for improving impact resistance while preserving mechanical integrity.

목차 (Table of Contents)

• 1. 서론 1
• 1.1. 연구 배경 1
• 2. 실험 및 방법 5
• 2.1. 실험 재료 5
• 2.2. 시편 제작 7
• 2.2.1. GNPs 분산 공정 및 Matrix 준비 9
• 2.2.2. 복합재 시편 제작 11
• 2.3. 점도 측정(Viscosity measurement) 14
• 2.4. 미세 구조 분석(Scanning electron microscope, SEM) 15
• 2.5. 인장 강도 시험(Tensile test) 16
• 2.6. 굴곡 강도 시험(Flexural test) 19
• 2.7. 낙하 충격 시험(Drop weight impact test) 22
• 2.8. 손상 평가(C-scan) 24
• 3. 결과 및 고찰 25
• 3.1. GNPs 첨가 에폭시 수지의 유변학적 분석 25
• 3.2. SEM 분석을 통한 GNPs 분산 상태 평가 28
• 3.3. 인장 강도 결과 및 분석 31
• 3.3.1. GNPs 첨가에 따른 인장 강도 변화 31
• 3.3.2. 아라미드 섬유 혼성화에 따른 인장 강도 변화 33
• 3.4. 굴곡 강도 결과 및 분석 38
• 3.4.1. GNPs 첨가에 따른 굴곡 강도 변화 38
• 3.4.2. 아라미드 섬유 혼성화에 따른 굴곡 강도 변화 40
• 3.5. 낙하 충격 시험 결과 및 분석 44
• 3.5.1. GNPs 첨가에 따른 낙하 충격 특성 분석 44
• 3.5.2. 아라미드 섬유 혼성화에 따른 낙하 충격 특성 분석 48
• 3.6. CAC 0.6 시편의 기계적 물성 평가 53
• 3.6.1. CAC 0.6 시편의 낙하 충격 특성 53
• 3.6.2. CAC 0.6 시편의 인장 및 굴곡 강도 평가 54
• 3.7. 복합재 시편의 충격 손상 분석 60
• 3.7.1. 충격 손상 시편의 거시적 분석 60
• 3.7.2. C-scan 분석을 통한 내부 손상 평가 64
• 4. 결론 68
• 참고문헌 70
• Abstract 77