A theoretical framework underlying an accelerated testing method and its application to composites under constant strain rates and fatigue loading

A theoretical framework that underlies an accelerated testing method for unidirectional (UD) composites is proposed in this article, based on the continuum damage mechanics and time-temperature superposition. By the way of demonstration, it has been applied to problems involving constant strain rates and fatigue loading conditions. The damage evolution law for the matrix of composites was constructed using the Weibull distribution of defects, which will develop into cracks as a result of deformation. In conjunction with the Wiechert model, the theoretical framework formulated here is capable of capturing the mechanical behaviour of UD composites. Demonstration and initial verification of this acceleration method were carried out through experiments. This work can provide theoretical and technical support for the durability verification and the evaluation of the high cycle fatigue performance of composite structures.