평직 UHMWPE/탄소섬유 하이브리드 적층재의 혼합 Ⅰ/Ⅱ 모드 적층분리에 의한 파괴저항 거동

Abstract

Many studies on the light weighting of mechanical devices and structures have been carried out in order to improve efficiency and reduce the cost. As a result, the studies for various composite materials have been conducted and applied to the industries. Particularly, the performance of composite materials in case of hybrid laminates can improve using different types of reinforced fibers. The carbon fiber has a thermal expansion coefficient close to zero, and shows high specific strength and stiffness except brittleness property. UHMWPE fiber is also excellent in cutting resistance and chemical resistance. Thus, the hybridization of carbon fiber and UHMWPE fiber results in highly complementary improvement. In this study, plain carbon fiber and UHMWPE fiber are hybridized into laminated composite and evaluated its mechanical properties and delamination fracture resistance under mixed I/II mode. From the result, crack extension length was carefully monitored and the energy release rate was applied to the fracture resistance evaluation. G<SUB>Ic</SUB>, which represents the interlaminar fracture toughness as a critical energy release rate, was obtained as 107.3 J/㎡, 70.43 J/㎡ and 19.39 J/㎡ for a<SUB>0</SUB>/L = 0.3, 0.4 and 0.5, respectively. G<SUB>IIc</SUB><SUB></SUB>, which represents the interlaminar fracture toughness as a critical energy release rate, was obtained as for a<SUB>0</SUB>/L = 0.3, 0.4 and 0.5, respectively. It shows that the energy release rate decreases as the initial crack length increases.