| With high specific strength and high specific stiffness, carbon fiber/resin composite laminateshave been more and more widely used in modern aircraft structures design. As an important part incomposite, composite repair have a significant effect on the aircraft usability, maintainability and eventhe service time. We could predict the huge and hard repair work of composite aircraft structures infuture from the heavy repair workload of the mass of metal aircraft structure at present. As a result,the research of composite bonded repaired structures is important in both academic researches andengineering applications.With the3D hashin failure criteria used to judge the composite damage and the maximum shearstress criterion used to judge the adhesive damage, the progressive damage analysis is used to analyzethe scarf repaired structure based on the failure criteria and the predetermined stiffness degradationstrategy. Firstly, the ultimate strength of both unpenetrated scarf repaired laminate and the penetratedscarf repaired laminate has been calculated and compared to the experimental data to make sure themodel validation. And the analysis of the stress distribution and the process of progressive damage ofthe two structures is further conducted. Secondly, based on the mentioned progressive analysis model,the relationship between the scarf angle and the strength (the ultimate strength and the initiativeadhesive failure strength) is discussed under three kinds of in-plane load (tension, shear andtensile-shear). And how the scarf angle influences the ultimate strength is analyzed according to thestress distribution and the damage expansion.. And some useful conclusions for engineering have beenachieved. At last, the influence of the external layer to ultimate strength of the scarf repairedcomposite structure is discussed based on the stress distribution and the damage progress. And the theinfluence of the chamfer to the ultimate strength of the scarf repaired structure is also analyzed. |
