Prediction of creep rupture of unidirectional carbon fiber reinforced polymer composite

A creep model, which was used successfully in a previous paper to model the creep of cross-linked epoxy resin as well as unidirectional carbon fiber reinforced epoxy composite, is used along with a fracture criterion to predict creep rupture at temperatures ranging from near Tg to far below Tg when the epoxy matrix of the composite is in the glassy state. This model, whose parameters have been measured by separate experiments, enables the separation of the part of the work stored from the part dissipated. A critical energy is proposed as the fracture criterion. Using the model, the time-dependent increase in stored elastic energy is calculated. Fracture occurs when the stored elastic energy equals the critical energy. The implication of temperature-dependent fracture mode in creep rupture prediction is discussed in terms of the temperature dependence of the critical energy.