The study on the decay law of Weibull distribution shape parameters for the residual strength of composite materials

Abstract

During the fatigue process, the variability in the residual strength of the composite gradually increased. This paper examined the transformation law of Weibull parameters for residual strength as a function of cycle count using experimental data and a literature review. The findings indicated that the attenuation of the shape parameters was tied to the degradation behavior of residual strength. Data from three distinct composite systems further indicate an approximately linear relationship between the shape parameter and residual strength, although additional validation is required under other loading and material conditions. A revised Weibull distribution model was introduced, enhancing the decay law of the shape parameters. The model better described the shape parameter, enabling accurate prediction of the variability in residual strength. With known Weibull parameters for material strength and fatigue performance, along with the law governing the weakening of residual strength, the probability distribution of strength after any number of cycles could be estimated.