Strength And Stiffness Analysis Of A Test Module For Aero-engines Under Complex Load Conditions

The aero-engine is the heart of an aircraft,and its complex working conditions determines the difficulties of the designing and manufacturing process.As an aero-engine test platform,the test module for aero-engines undergoes multiple loadings including internal pressure,external pressure,thermal load,pipe load and seismic load.Due to the complicated structure and various loading conditions,it is hard to perform accurate strength design by rules based on available codes,letting alone the fatigue analysis.In this thesis,the numerical simulations of a test module for aero-engines under complex loading conditions were carried out.The main work and conclusions are as follows.(1)Geometry model and finite element model of the test module for aero-engines were established with ANSYS Workbench software.The solid shell elements were used for meshing the geometry model.Loadings considered in the analysis include internal pressure load,gravity load,temperature load,pipeline thrust load and seismic load.Twelve working cases were specified.(2)Thermo-mechanical analysis of the test module for aero-engines was performed.Conforming to JB4732-1995 Steel Pressure Vessels-Design by Analysis,strength assessment was conducted on all parts of the test module for aero-engines.To solve the problem of excessive deformation at the hatch frame,deformation-resistant ribs were specially designed and with them the deformation of the hatch frame is greatly reduced and the hatch door can open and close smoothly.(3)Fatigue analysis for the test module was conducted.According to the fatigue design curve and formulas,the allowable cycle numbers and the fatigue damage factors of shells of the pre-chamber section and the test chamber section under twelve operating conditions were calculated.The values of cumulative fatigue damage factors are 0.3942 and 0.91065 respectively,implying that both parts meet the fatigue strength requirements.(4)The test module for aero-engines may undertake external pressure.In order to ensure the tightness and integrity of the equipment,linear stability analysis under external pressure of 0.1 MPa was performed.The ratio of critical buckling load to design external pressure is 7.7855,more than the safety factor of 7 which is specially required by the user.So the device will not buckle under the designed external pressure.(5)The natural frequency of the test module for aero-engines was obtained by conducting modal analysis.According to NB/T47041-2014 Tower Container,the horizontal seismic acceleration is calculated and value is 0.07g.Thermo-mechanical analysis of the whole equipment under seismic conditions was completed.The strength assessment of pre-chamber section and the test chamber section were performed.Results show that their strength under the action of seismic conditions meets the relevant strength requirements.(6)The finite element analysis was also performed on the test module for aero-engines under the limiting explosion case involving the internal pressure of 0.2MPa.It is found that the strength and deformation of the shell of test chamber section and the hatch door under the explosion load case can meet the requirements.