Fatigue life prediction of composite suspension considering residual stress and crack propagation

Composite materials are widely used in the automobile industry, compared with traditional mechanical connection, in terms of efficiency and manufacture cost structure, adhesively-bonded joints are usually the material most appropriate connection technology. Adhesively-bonded joints have good performance under fatigue load and the stress concentration is smaller. Lack of reliable design methods, long-term aging behavior, and fatigue life assessment of the adhesive joint, which are limits the bonded joints technology popularization and application. In order to describe the crack propagation process more accurately, an improved generalized crack propagation model was proposed to predict the fatigue life of composite bonded parts. The crack propagation process is divided into three stages, and the influence of machining technology, residual stress, and actual temperature in the process of machining are considered. The model provides an effective theoretical basis for accurately predicting the residual life of composite bonded structures. Experimental and simulation results show that the proposed model expands the prediction range of the existing theoretical model, and the prediction accuracy is significantly improved.