Long-Term Creep Rupture Prediction in Unidirectional Composites

Abstract

In many articles, analyses about creep behavior and creep rupture in unidirectional composites have been done in the past two decades. McLean [1] formulates the creep behavior in unidirectional composite with a simple constitutive equation in matrix. Curtin establish the GLS theory that can determine a rupture strain in unidirectional composites. By combining these two models, Du and McMeeking et al. [3,4] and Ohno and Miyake [5,6] predict the creep rupture in unidirectional composites. However, several problems are pointed out: an interfacial debonding is not considered, McLean model can not express the exact creep behavior. On the other hands, the previous author’s works [7] and Okabe et al. [8] show that micro damages such as an interfacial debonding causes the composite rupture strain to decrease. That is to say, the rupture strain in unidirectional composite has time-dependency on an assumption that the interfacial debonding propagates or the stress recovery length increases with time. However, the decrease of the rupture strain has not been formulated on a consideration of history dependent accumulation of micro damages. The fact results in that the predicted creep rupture time is overestimated. This is because despite of there is an interaction between stress recovery length and fiber breaks probability, the formulation has not been done.