| In this paper,vibration characteristic of an aeroengine stator system is analyzed under transient temperature field caused by uneven temperature distribution in some working condition.Three-dimensional finite element model of the stator system is set up.Incorporated temperature boundary condition,finite element method is used to calculate the steady temperature field and transient temperature field.General elasticity mechanics method is used,and temperature effect is taken as thermal load to calculate thermal stress.Metallic material thermal physical parameters,like modulus of elasticity,are also considered,as they are temperature-dependent.The new thermal stiffness was obtained to calculate the natural frequency of the structure.Alloy material thermal natural vibration characteristics were analyzed under normal atmospheric temperature,steady temperature field and transient temperature field respectively.And response characteristic under normal temperature and steady temperature is calculated and analyzed.In this paper,response of front and rear vertical support of the engine under transient temperature is analyzed in five seconds by transient dynamics method.Conclusions are as following:high-order natural frequencies descend faster as temperature increase.Thermal stress caused by temperature reduces natural frequencies.Frequencies drop faster under combined effect of temperature field and thermal stress.In convection temperature field,temperature change and vibration change are more obvious.In the beginning of heating-up,temperature change is very fast,and frequencies drop fast.When temperature field tends to balance,frequencies also tend to some stable values.Temperature has different effects on response at different supports.Resonance frequencies decrease.Between 0 and 285Hz,vertical displacement at supports increases.Near 195Hz,horizontal displacement at front and middle supports decrease,at other frequencies displacements increase. |
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