Assembly Variation Analysis And Prediction Of Flexible Parts Of Aeronautical Panels

The structure of aircraft is complex, which contains various types and numerous parts and a large number of compliant thin-walled structures composed of sheet metal parts. In order to ensure the aerodynamic shape accuracy of aircraft, these kind compliant parts need a lot of special assembly fixtures and other process equipment during assembly. Due to the manufacturing error of parts and the locating variation of assembly fixture, compliant parts are subject to complex assembly forces during assembly, and inevitably generate assembly deformation and deviation, which seriously affect the manufacturing quality and performance of aircraft. According to the existing researches are not apply well to aircraft assembly process, this paper focuses on the aeronautical panel as the typical thin-walled structure, and analyses the formation mechanism of the assembly fixture locating error and assembly deviation, and establishes the analysis model of fixture locating error and assembly deviation. The main research contents and results are as follows:The typical structure and the assembly process of aeronautical panels are combed. The methods of assembly variation analysis are introduced, which include the assembly variation analysis models and the solving methods. The scope of application and the method of modeling for rigid and compliant assembly variation analysis are summarized. The advantages and disadvantages of these solving methods are discussed. On that basis, the technical route of assembly variation analysis of aeronautical panels is raised.A locating variation model of working surface of fixture board and A statistical analysis method for the model are proposed. On the basis of the analysis of the characteristic of the location and the stress state of fixture board, a relation model of the locating variation of working surface of fixture board caused by the locating deviation based on an enhanced dimensional reduction method is proposed. Because of the high nonlinear of the variation model and in order to improve the solving efficiency of variation statistical parameters, a method of statistical analysis of assembly variation based on an enhanced dimensional reduction method is proposed. Finally, the experiments of assembly variation of fixture board are carried out. The method of variation statistical analysis based on an enhanced dimensional reduction method, the assembly simulation based on a 3DCS software, and the direct Monte Carlo simulation based on the locating variation model are contrasted. The result shows that the method proposed by this paper has a good consistent with the latter two methods, and improves computational efficiency significantly.A model of assembly in parallel for the assembly of aeronautical panels is proposed. And then the assembly deviation propagation for the assembly of aeronautical panels is modeled. According to the locating method and the characteristics of the assembly of aeronautical panels, a model of compliant assembly in parallel is proposed. Mechanical analysis for the model based on the assumptions of small deformation and linear elastic is carried out. Then according to the characteristics of the assembly of aeronautical panels, the assembly deviation propagation for the assembly of aeronautical panels is modeled. Finally, for two assembly cases, the methods proposed by this paper and the assembly simulations based on ABAQUS are applied to solve assembly deviation. And the result shows the effectiveness of the proposed assembly variation model, which provides theoretical and technical means for the assembly variation analysis prediction of aeronautical panels, as well as a theoretical basis for the further tolerance analysis.