원공을 가진 샌드위치 복합재의 좌굴 및 후좌굴 거동에 관한 연구

다국어 초록 (Multilingual Abstract)

General jointing methods of sandwich composite have been using the adhesive bonding, mechanical jointing and hybrid joint. In case of mechanical joint, sandwich composites have holes. This study is covering the evaluation for the properties of sandwich beam with hole that is applied to compressive load. The sandwich composites was consisted of the face made of glass fiber/epoxy resin with 1.7 ㎜ thick and urethane-foam core with 23, 37, 48 and 61 ㎜ thick. The sizes of hole were considered 25 ㎜ diameter and 38 ㎜ diameter at center of beam. At first, on comparing the results of experiment with theoretical results, it is confirmed that the boundary condition of testing fixture expressed the pin-ended condition properly. As a result, the buckling load and maximum load of sandwich beam with 25㎜ dia. hole were declined less than 10 % of baseline. And, them of sandwich beam with 38 ㎜ dia. hole were dropped less than 30 %. Major failure modes were core shearing for thin beam. But, thick beam was broken such as delamination or debonding.