Research On Assembly Manufactur Ability And Tolerance Analysis Of The Tail Of An Airplane

Tolerance Analysis for digital assembly is the important means to verify the desirabilityof tolerance distribution, to improve the accuracy of assembly and ensure the success rate ofdisposable assembly. The research contents of tolerance analysis covers various aspects likeassembly process, tolerance modeling, dimension chain extraction and tolerance analysiscalculations. The research on tolerance analysis for aircraft components, not only for theapplication of tolerance analysis calculations, but also the system engineering established onthe study of assembly process for the entire aircraft components. In this paper, an aircraft tailsection as the research object, the assembly process and tolerance analysis problem arestudied system.By analyzing the manufacturing process characteristics of the tail section, contents of theassembly process design of the tail are studied. The difference between the traditional anddigital model is determined on aspects such as assembly structure division, assembly locationselection, and assembly reference determination and compensation methods application. Theassembled coordinated program of the class components is designed, such as planecomponents, double-curvature planes, door and cover components and fuselage components.According to the study of two coordination accuracy problem as shape coordination andintersection coordination on aircraft assembly, the positive impact of error accumulation bycoordinating with digital ways is analyzed and the assembly dimension chain about orderdifference of fuselage skin and center distance of installing fork of the structure of the tail isestablished.The MBD tolerance model is established based on the hierarchical structure of features.The definition of key characteristics and the representation in the structure tree is analyzed.The expression of tolerance information and the extraction of3D dimension are realizedbased on CAA. The principle of automatic generation of dimension chain is analyzed and thetolerance database is established based on SQL Server.The algorithm of tolerance analysis such as the extreme value method, the probabilistic method and Monte Carlo method is studied. With these methods, class dimension chains ofthe tail are calculated and the using condition and the pros and cons of the three methods aresummarized.Finally, with the technology of secondary development of CATIA, the tolerance analysisprototype system is developed to realize functions like tolerance modeling,3D dimensionextraction, reading&storage of dimension chains and tolerance analysis.