Research On Stiffness Caculating Methods Of Bolt Connected Thin-wall Casing Structures

The casing is a key component and a major bearing parts of the Aero-engine. And itsstructural performance is directly related to the reliability and longevity about the engine. Thebolt connection is the main connection of the Aero-engine casing. It has a great impact aboutthe casing vibration characteristics and stiffness. This paper focuses on the stiffnesscalculation about the bolt connection of the thin—walled casing.In the process of the engine design, analysis of its dynamic characteristics, the traditionalway to analysis the vibration characteristics of the bolt was usually ignored, when the enginecharacteristics were analyzed. The true vibrations characteristics of the engine can’t beaccurately reflected when the calculation was simplified. While during the design of thebolted jointed for the Aero-engine casing, it’s mainly depended on the design criteria and theexisting experience of the designer to determine the geometric parameters of the structure.And usually they only consider the structure of the characteristic parameters for the dynamicscharacteristics, but not considering the specific geometry of the structural dynamics. Thispaper is mainly based on the finite element method. The “L” shaped bolt connection structurewere analysis about the modal calculations、bolt simplified and transfer functions, thencompared with the experimental structure. Verify the parameter settings and the accuracy ofthe bolt simplified method about the calculations. On the basis of that, the parametermodeling about the horizontal and vertical casing was built. The installed casing thicknessand edge thickness, height, casing and edge transition radius were analysis，then find out itschange on the influence of the stiffness about the structure. Then the mass and stiffness of thestructure were regarded as the optimized objected, the parameters were the optimizationvariables. Respectively optimize the horizontal and vertical casing, and find out the bestcombination of the parameters. Finally the low pressure compressor casing of the aero-enginewas regarded for the example. Based on the above parameter setting method, bolt simplifiedabout the low pressure compressor’s modal analysis and stiffness was calculated. Throughthis study, it can verify the correctness of the method for calculating and the accuracy of the calculation results, it can provide some useful reference for the development and modificationof the bolt structure, and has a certain reference value for the similar bolt connectionstructure’s dynamic calculations.