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もどる
Abstract: Carbon fiber reinforced facing/aramid honeycomb core sandwich beams were studied through three point bending test. In order to clarify the influences of water on the stiffness and strength, the dry and wet specimens were used. At the same time, the fractured specimens were inspected by a scanning electron microscope (SEM) and a scanning acoustic microscope (SAM) to observe the fracture surfaces and interior damages of the specimens, respectively, and the fracture mechanism was discussed. The experimental resulsts showed the following. (1) With 6 wt.% water absorption the flexural stiffness of the sandwich composites rises a little while the shearing stiffness falls by 11%. (2) The core shearing strength and core shearing strength are 9% and 18% lower, respectively. However, the decrease has a tendency to level off over 4 wt.% absorption ratio. (3) The bonding strength between the facing and the core is larger than the matrix. (4) The buckling axes observed in the compressive fracture surfaces are more seen in a small span length (<200mm), the wet specimens deflect more than the dry specimens, which is due to the degradation of the aramid fiber paper of the cell wall. Key words: Sandwich material, CFRP, Aramid honeycomb, Three point bending test, Bonding, Delamination, Strength, Stiffness, Water absorption, SEM, SAM |