PVC폼 코어 탄소섬유샌드위치 복합재의 모드Ⅰ 층간분리특성에 대한 실험적 분석

Abstract

The light weight composite materials have been replacing in high performance structures. The object of this study is to examine the effects of the initial crack location on the delamination in a PVC foam cored sandwich composite that is used for the strength improvement of structures. To analysis the effects of the initial crack location on the delamination, the thickness of fiber laminates were changed with three types. The ModeⅠ specimen was used for evaluating the fracture toughness and crack behaviors. The material used in the experiment is a commercial twill carbon prepreg in CFRP material and Airex in PVC foam core. Sandwich laminate composites are composed by PVC foam core layer between CFRP face sheets. The face sheets were fabricated as three types of 3, 5 and 8 plies. The initial cracks were located in a PVC form core and the interface of upper CFRP sheet. From the results, the crack initiation was affected with the location of the initial crack inserted in the PVC foam core. The initiation of the crack irstly affected by the initial crack insertion location, and the initial crack insertion at the center of the PVC foam showed a rapid progress. Among them, the lamination of CFRP with 8 plies made the most rapid progress. And the critical energy release rate was 0.02 kJ/m², which is the lowest value when the initial crack was inserted into the interface between a PVC foam core and CFRP laminated with 3 plies at face sheet. Meanwhile, the highest value of 1.70 kJ/m² was obtained when the initial crack was located at the center line of PCV foam in case of the 8 plies face sheets.