라미네이트와 하니콤 샌드위치 구조물의 강도 특성에 미치는 Thermal Aging의 영향

Abstract

Composites are used in lots of field such as a part of aeronautic space, ship, machinery and so on because can make structure wished for necessary condition by control fiber direction and laminated sequence.

Aerospace industries are widely using honeycomb sandwich structures that it has high specific strength, stiffness, chemical material resistance and fatigue resistance. As the use of advanced composites increase, specific techniques have been developed to repair changed composite structures. In order to repair the damaged part, it is required that the material in the damaged area be removed first by utilizing the proper method, and prepreg be lay up in the area and cured under vacuum using the vacuum-bagging materials. However in curing process, either in an oven or autoclave is to be delamination can be occurred in the sound areas during and/or after the exposure to the elevated curing temperature in case that the repair process is repeated although autoclave curing using the vacuum-bagging becomes virtually mandatory for advanced composite repairs, in order to achieve the required compaction and proper consolidation of the repair materials and prepreg can sometimes be repaired with either or wet materials in field condition, autoclaves for repairs are rarely necessary. In order to repair the damaged part production high quality composites are completed by control the surrounding temperature and pressure in autoclave. The quality is influenced heat exposure degree by chemical reaction for processing.

Therefore, this study was conducted tensile, compressive, interlaminar shear strength tests of the laminate composites structures and flatwise, drum peel, long beam flexural strength tests of honeycomb sandwich structures by affecting thermal aging to evaluate how it affects to the composites materials of aircraft by measure the change of mechanical properties according to heat exposure degree for repairing. As the result, the change of mechanical strength was observed at the honeycomb sandwich structure which is exposed to hear several times, but the laminate composites structure was not .

Consequently, the control of curing cycle times and curing condition is recommended for parts in order to reduce the delamination phenomenon between laminate skin and honeycomb core to the minimum in case that the repair process is repeated.