| Composite structures will inevitably be damaged in use,so it is necessary to repair the damaged parts.The scarf repair of composite materials is a new repair technology by removing damaged materials and adding patches to fill them.The purpose is to recover the shape,strength and stiffness of the structure before damage and to meet the requirements of mechanical properties by removing as little material as possible from the original structure.Composite structures are not only subjected to static loads,but also to fatigue loads,so it is also very important to study the fatigue performance of scarf repaired structures.In this paper,the static strength and fatigue residual strength of composite material repair structure are mainly studied.Firstly,on the basis of three-dimensional progressive damage theory and three-dimensional failure criterion,a model of scarf repaired structure is established.The model is simulated under static tension load,thus the failure damage process of the repaired structure is explored,and the final failure strength of the repaired structure is predicted.The predicted data are in good agreement with the experimental results.Secondly,the main influencing parameters,such as patch size,adhesive thickness and repair angle,are selected in this paper.The effects of these parameters on the repair effect are analyzed by numerical simulation,and some suggestions are put forward for the selection of parameters in the process of scarf repairing.Finally,the fatigue performance of scarf repaired structure is studied.According to the theory of progressive fatigue damage,a program is compiled to observe the fatigue damage propagation process of the structure by applying a certain number of fatigue loads.The fatigue residual strength of the structure subjected to fatigue load is predicted and compared with the static strength.And the effects of patch size and adhesive thickness on fatigue properties were investigated.In addition,two-stage fatigue loading was also studied. |
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