| As the starting of commercial aircraft project, the development and application of high performance panel is one of effective ways to improve the life, reliability, economics, safety and comfortableness of the airplanes. Thus, the research of civil aircraft fuselage panel is necessary. The thesis includes the analysis and experiments of the present fuselage structures under shear load and axial compression load, and the numerical analysis of ditching.At first, the test results of failure modes, failure loads and the curves of allowable shear flow with area of the stringers, frames and the thickness of the skin were implemented by 16 configurations of build-up panels under the shear loads. In the comparison between the test results using different panels made of imported materials and domestic materials respectively, the calculated stress has been modified. There are only four estimation values of panel configurations are higher than the test results under the corrected allowable shear flows. Moreover, the errors are less than 5% and meet the requirement of engineering. According to the comparison between the calculation of nominal panel thickness and measured thickness, it can be found that the panel failure shear flows are close. This indicates that once the error is controlled within the tolerance range, the deviation of the skin thickness would not affect the panel shear strength.Secondly, the experiments of 11 build-up panels under the axial compression loads have been carried out. And then the results of the failure modes and failure loads have been obtained. On the other hand, the assessments of three approximate computational methods have been implemented. Based on the experiment, it is found that Johnson's Parabola Method is the closest to test results. Nonlinear finite element models on the test validation have been built up. Through the analysis of the section dimensions sensitivity, it reveals that the main effect of axial compression load is the cross-sectional area of the stringer, whose sensitivity coefficient is 44.2%. And the panel precise response surface polynomial of the axial compression is given. According to the finite element calculation on the equal weight design, the failure mode is different from the build-up panel: the integral panel stringers do not show obviously crankle and reaches the plastic yield stress of the skin till damaged at last; moreover, the maximum of axial compression is improved 18.4% compared with the build-up panel. According to the finite element calculation result, the valid skin width in the Johnson's Parabola Method for the integral panel has been defined. Then, the integral structure has been optimized by using the Multi-Island Genetic Algorithm and Sequential Quadratic Programming. Compared to the initial design, the weight after optimization is reduced by 8.8% and the strength remains same, which is very valuable for the design of integral panel.At last, the rigid and elastic models of an aircraft ditching have been built respectively. Through the SPH unit simulation in a meshless method, the results both show effects of the splashing and sloshing flow to the airframe structure strike. Base on the simulation of ditching rigid model, it has been obtained the ditching track and deceleration-time curves of each part of the aircraft. The analysis result indicates that the release of the landing gears could cause transverse oscillation and increase the transverse instability, therefore, the best ditching attitude is identified as: landing gears retraction, flap deflection and the attitude angle to dipping water is 7°. On the other hand, the calculation of a partial elastic body in the passenger section is carried out, which obtains that the response of airframe structure under water strike, and also checks the structure integrity under the maximum sinking velocity of the aircraft. All the tests and calculations above provide a valuable reference to the design of fuselage and airworthiness verification.
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