Abstract
In order to apply natural fiber reinforced biomass plastics, i.e. green composites, to load-bearing structures, the fatigue property of natural fibers should be well understood. In this study, fatigue property and fatigue damage accumulation process of jute monofilament was investigated by conducting axial loading fatigue tests. Fatigue strength of each jute monofilament was determined by using a cross sectional area corresponding to the fracture portion. Fatigue strength of jute monofilament decreased with increasing the number of cycles to failure. The fatigue strength at 106 cycles was about 50% of the tensile strength. SEM observation of fiber surfaces showed that fatigue cracks occurred in elementary fibers at low cycles and the fatigue cracks propagated with increasing the number of cycles, while reduction of fiber stiffness was not found at low cycles. This implies that the fatigue cracks which were observed in the early stage nucleated and propagated only in the intercellular layers and/or primary wall and did not penetrate into the secondary walls of elementary fibers.
