941 一方向 FRP のクリープ寿命予測 : 繊維破断部近傍の界面はく離を考慮したクリープ破断モデル

Abstract

This paper describes the creep rupture model considering the interfacial debonding and its propagation from the end of broken fibers in unidirectional polymer matrix composites reinforced by glass fibers. Interfacial debonding is accompanied with fiber breaks under the tensile load, which develops longer. In the present study, the interfacial initial debonding length, the fiber strength and the interfacial shear stress are investigated by the fragmentation test. The interfacial debonding propagation is also investigated by the creep test or the constant strain test with the use of a single fiber within a polymer matrix specimen. The interfacial debonding length is taken into the modified Curtin-McLean's creep rupture model. This modified creep model does not have the threshold stress, because the failure stress in this model decreases according to the interfacial debonding propagation as time progresses. The predicted life of a creep rupture is shorter than that of the conventional model and there is no threshold stress in the long-term creep.