| 초록 |
Interfacial shear stress (IFSS) can be affected by the stress distribution and stress concentration. Fiber fracture leads to stress transfer to the vicinity fibers immediately. 3D-hexagonal boron and glass fibers/epoxy composites were prepared to measure the effect of stress transfer, and the inter-fiber distances were controlled precisely. Flexibility of the epoxy matrix was controlled by the change in the relative proportion of D230 versus D400 in the curing mixture. The inter-fiber distances were adjusted with respect to the diameter ratio, respectively. The change in IFSS and debonded length between hexagonal fiber and matrix were measured using tensile fragmentation test. The specimen with short inter-fiber distance was affected by each fiber fracture, whereas in long inter-fiber distance case, they were almost independent to adjacent center and side fibers. A FEM simulation to clarify the effect of IFSS was performed by shear lag theory with Weibull parameters. For both boron and glass fibers, IFSS measured by FEM simulation was compared with the IFSS measured by tensile fragmentation test. Acknowledgement: This study was supported financially by KoSEF through the Research Center for Aircraft Parts Technology (ReCAPT), GNU. |
