Experimental Verification of an Accelerated Test for Predicting the Lifetime of Organic Fiber Composites

Abstract

We have experimentally tested a model which is used to predict the stress-rupture lifetime of organic fiber composites. The experiment con sisted of a series of accelerated stress-rupture tests in which an aramid fiber impregnated with an epoxy resin was subjected to high temperatures and stresses. The resulting data were used to generate the model's material constants. The model was then used to predict the median lifetime of the composite at stresses and temperatures lower than those of the accelerated tests. A comparison of the model-predicted lifetimes at 25°C with 4 years of known stress-rupture data at room temperature showed that the experi mental data were in good agreement with model-predicted values. In a statistical analysis of the results, a Weibull distribution function with temperature-dependent parameters was assumed to describe the variability of lifetimes about the median lifetime.