The Rigid-flexible Coupling Assembly Deviation Modeling And Process Optimization Method Of The Aircraft Panel

Aircraft assembly is the key link of the aircraft manufacture, theworkload of which occupies about40~50percent of the whole aircraftwork output, and how to effectively control the assembly coordinationaccuracy of aircraft assembly is one of the key technologies of aircraftmanufacture. Furthermore, the assembly coordination accuracy of fuselagedirectly affects the overall shape and dimensions matching performance,flight safety and the fatigue life of structure.The structure and coordination route of aircraft panel is complex, sothe profile assembly quality is very difficult to be controlled. The accuracyof traditional dimension chain method is not high because it mainly takesrigid deviation into account. Along with the digital technology with digitalquantity transfer as the core in place of the traditional way of analogquantity transfer, the study on assembly deviation modeling of aircraftpanel has become the urgent problem to improve the assembly accuracy.Rigid model has solved the geometry motion deviation during the partsassembly process, suitable for analyzing the rigid assembly deviation ofhuge numbers of parts and complex deviation source. However, due to thelarge size and low stiffness of skin, it is easy to deform in the assemblyprocess, as a result that flexible model must be brought in. Flexible modeltakes part’s local deformation into account, suitable for analyzing theassembly deviation due to flexible parts’ deformation. Nonetheless,because of the large solution scale, time-consuming and low efficiency ofthe pure flexible model, it will influence the aircraft development andproduction cycle.According to the difficulty to control the profile assembly quality of aircraft panel, the thesis puts forward the combination of the rigid andflexible analysis method to establish the rigid-flexible coupling assemblydeviation model. To be specific, the thesis adopts the deterministicpositioning method to calculate the rigid deviation and the finite elementsimulation to calculate the deformation of skin in order to predict theprofile deviation of aircraft panel and optimize the tolerance and otherassembly process, and finally achieve the profile deviation control. At last,this method is verified in the assembly deviation analysis of a domesticaircraft panel test piece.The main research work of this thesis is as follows:（1）Assembly process and deviation analysis of aircraft panelFirstly, the structure and assembly process is introduced in detail.Afterwards, it introduces the quality control target and evaluation methodof aircraft panel. Finally, it introduces the processing technology and testmethod of different parts, analyzes the source of error, and summarizes thedeviation source factors existing in the present assembly process.（2）Rigid-flexible coupling assembly deviation modeling ofaircraft panelFirstly, this thesis calculates the rigid deviation of aircraft panel in the3-2-1positioning scheme by deterministic positioning method. And thencombined with the method of influence coefficients it calculates thedeformation by finite element method. Finally, it establishes therigid-flexible coupling assembly deviation transfer expression by the unionof the rigid and flexible analysis method, compiles the calculationprocedure, realizes the Monte Carlo simulation, and predicts the measurepoint deviation of aircraft panel.（3）Assembly process optimization of aircraft panelFirstly, sensitivity analysis is conducted on the out-of-tolerancedimensions by the rigid-flexible coupling assembly deviation analysismodel, and the tolerance of shear tie DA hole is optimized as well. Andthen it calculates t the normal deformation of skin on the positioning and clamping state by direct finite element method. Finally, combining themethod of influence coefficient and finite element method, the number ofstringer DA holes is optimized.（4）Application verification on the test piece of aircraft panelBased on the above research, the thesis applies the rigid-flexiblecoupling model to the assembly deviation analysis of the test piece of adomestic aircraft panel. Furthermore, it verifies the validity of the model.And through the optimization design of the skin clamping scheme, thefactory’s clamping scheme is improved.This thesis focuses on the assembly process of aircraft panel, bringsforward a rigid-flexible coupling assembly deviation modeling method ofaircraft panel, and achieves the control of profile deviation. This methodnot only is applied to the independent research of domestic regional jetARJ-21, domestic big civil aircraft C919and all kinds of other subsequentcivil aircraft but also has reference significance for the assembly deviationanalysis of all kinds of other thin-walled structures.