A fatigue damage accumulation model based on stiffness degradation of composite materials

Abstract

Many of the stiffness-based fatigue damage models contain four main limitations for composite materials life determination: (i) lack of capability in simulating the whole periods of damage evolution, (ii) applicability for a specific type of composite and in a limited range of loading levels, (iii) existence of many parameters in the models requiring substantial experimental data, (iv) application for constant amplitude loading only. In this paper, a stiffness-based fatigue damage model is proposed aiming to address the posed shortcomings. Nine sets of experimental data are utilized for this purpose. The results show that the model succeeds in dealing with these limitations. Then, a life prediction model is developed based on the damage model for two-stage loading. The model is assessed by three sets of experimental data and compared with some existing models. The comparison demonstrates that the model predictions are promising for remaining fatigue cycles in comparison with the studied models.