Al/CFRP 하이브리드 복합재료 인장 파괴에 관한 연구

Abstract

The hybrid composite materials are recently used in many field as an advanced materials due to its high specific strength and the resistance to fracture. However, hybrid composite materials have several problems, especially delamination, compared with common materials such as an aluminum alloy, etc. In this study, we carried out the tensile test to study the failure appearances of CFRP/Al/CFRP and Al/CFRP/Al hybrid composite material. The results show the inserted aluminium thickness has an effect on CFRP failure mode. The material used in the experiment is a commercial material known as CU175NS in unidirectional carbon prepreg (Hankuk Carbon Co.). A universal dynamic tester (50kN) of H. Co. was used for measuring. The crack length was measured by a traveling microscope. The following conclusions could be drawn from this study. 1) In case of CFRP/Al/CFRP hybrid composite for Al thickness 0.3mm, it can't prevent an abrupt brittle fracture, because CFRP and Al are completely fractured in the same time. In case of CFRP/Al/CFRP hybrid composite for Al thickness 0.5, 0.8mm, prevent an abrupt brittle fracture even though the interfacial fracture is occurred in the entire specimen. 2) In case of Al/CFRP/Al hybrid composite for Al thickness 0.3mm, Al has a rapid crack growth as soon as CFRP is fractured. In case of Al/CFRP/Al hybrid composite for Al thickness 0.5mm, Al has a rapid crack growth as soon as CFRP is fractured, but an entire specimen fracture is prevented. In case of Al/CFRP/Al hybrid composite for Al thickness 0.8mm, Al prevents a rapid crack growth and abrupt fracture when CFRP is fractured. In addition an entire specimen fracture is prevented. 3) In Al/CFRP/Al hybrid composite, KIC was respectively obtained 93, 184 and 191MN/m^(3/2) along a0/W for Al thickness 0.3mm. Those of Al thickness 0.5mm was respectively obtained 117, 157 and 187 MN/m^(3/2). Those of Al thickness 0.8mm was respectively obtained 87, 123 and 151 MN/m^(3/2). Δa was decreased according to the increasing Althickness.