Research And Structural Optimization Design Of Bolted Joint For Aero-engine Stator Casing

The bolted joint is a mode of connection which is widely adopted in Aeroengine Casing. As a connection, strength and reliability of bolt connectionstructure concern to the safety of structures which include it, the whole Casingeven Engine. And weight concerns to the effection of the whole engine whichaffects the engine performance index. The method for traditional structuredesign of Casing is mostly based on the design criterion and experience equation.Just bolt connection structure is concerned, these methods in some extent ensurethe structural strength and reliability, but causes the waste of material atthe expense of its weight for the price. Bolt most have strong stressconcentration in actual use process, some parts have greater strength margin.Therefore, problems which include reducing the maximum stress of bolted jointand guarantying the reliability of the structure and reducing the structureweight are urgently needed to be solved. The multi-objective optimization design of bolted joint for Aero engineStator Casing can be performed well by the effective combination of responsesurface method, finite element method and optimization method. At first, theorthogonal experimental design based on response surface method was used todetermine the combination of geometrical parameters (such as installation edgeheight, thickness and the number of bolts) for bolt connection structure. Theparametric modal and numerical calculation of bolted joint for which haddifferent geometrical parameters were simulated and analyzed by using APDLlanguage, and the calculated value of maximum equivalent stress and quality werealso calculated. Then, through the regression analysis, the response surfacemodal of maximum equivalent stress and mass were obtained. Next, the mathematicalmodal of multi-objective fuzzy optimization design which chose the maximumequivalent stress, quality and reliability index as the objective function wasestablished through the multi-objective fuzzy optimization design method, andthe optimal structural parameters and solution of bolted joint were obtainedby using MATLAB software. Finally, the optimization design results were analyzedand verified by finite element method to make sure the optimization method isfeasible. The results showed that the results of multi-objective fuzzy optimaldesign and finite element numerical simulation were basic consistent with eachother; After multi-objective optimization, The maximum equivalent stress forbolted joint was lower18.3%than that the original one, the mass of the structure was lower5.7%than that the original one, changes for reliability index is notobvious, but both met the reliability requirement, and the comprehensiveperformance of structure was significantly improved, which could offerreferences to the structure design and the weight reduction of Aero engineCasing.