Research On Structural Optimization Design Of Four Web Fan Disk Of Aero-Engine

The fan disk,as one of the important components of the fan system,is subjected to huge centrifugal load from itself and the blade during normal operation,and its structure directly affects the overall performance of the aero-engine.The use of wide-chord fan blades can effectively improve the bypass ration of the engine,but it also results in the width of the fan disk rim and the mass of the disk to be increased.The four-web fan disk can effectively reduce the quality of the disk and improve the thrust weight ratio of the high bypass ratio turbofan engine.It has important theoretical significance and engineering practical value to optimize design for the four-web fan disk.This thesis mainly studies the optimization design of the four-web fan disk structure of the high bypass ratio turbofan engine,explores the two-dimensional simplified method of the three-dimensional four-web fan disk structure model and the load,and proposes a two-dimensional simplified model.Based on the two-dimensional simplified model,the optimization is taken for the four-web fan disk.The details are as follows:Firstly,the parametric modeling of the multi-web fan disk structure is implemented through the UG secondary development technology,and the solid model of the multi-web fan disk is created.In order to obtain a suitable fan disk structure,the fan disk structure of double-web,three-web and four-web fan disk are proposed,and the static strength analysis of this three different fan disk structures is carried out by finite element method.The static strength analysis results of this three finite element models are compared under two different constraints,the same total thickness of the web and the same stress level,to determine the suitable four-web fan disk structure.Secondly,the joint force of the four-web fan disk rim is extracted,which joint is on the common surface of the rim and the bump.The load simplification method of the three-dimensional four-web fan disk structure is studied,and a non-uniformly loaded axisymmetric model is proposed(two-dimensional simplified model).By comparing and analyzing the finite element simulation results of the periodic symmetric finite element model of the three-dimensional fan rotor,the two-dimensional axisymmetric model with uniform load and the two-dimensional simplified model,the feasibility of the two-dimensional simplified model is verified.The universal property of the two-dimensional simplified model was verified through applied it to double-web and three-web fan disk structures.Finally,the complex method is used to optimize the two-dimensional simplified model of the four-web fan disk.The optimal structure of the four-web fan disk is obtained,and the three-dimensional finite element model of the optimal structure is created for finite element strength analysis to verify the design result of the optimal structure.In summary,this thesis proposes a two-dimensional simplified model of multi-web fan disk by studying the load characteristics of the fan disk rim,and based on this,the structural optimization design of the four-web fan disk is carried out.The design method can effectively reduce the scale of the finite element model and the time of simulation,and improve the efficiency of optimization design.These efforts and results lay an important foundation for further research on the optimization design for four-web fan disk.