31th Congress of the International Council of the Aeronautical Sciences

04.2 - Structural Analysis and Design, Structural Dynamics, Aeroelasticity


J. Qin¹, X. Gao¹, W.C. Huang¹, G. Yao¹; ¹ASRI, China

The blade is the key dynamic part in aero engine?whose employment circumstance of high speed rotating and strong impact gas flow is so severe, which bears centrifugal load, air-actuated load, vibration load and so on. When the exciting frequency is closed to the natural frequency , resonance vibration will happen for the blade, which induce major dynamic stress and HCF for the blade, as a result, the disaster consequence could be encounter. In order to enhance the safe reliability and service life of the turbine blade for aeroengine, it's necessary to obtain the natural frequency of the turbine blade.rnThe structure of blade is rather distinguished, the internal structure is complicated especally. what's more, the frequency of blade is high and the quality of blade is little. In modal test, it is difficult to confirm the boundary condition, the location of exciter and response and the setting of exciter and analysis parameter. In addition, the different test method and analysis method will influence the final result and the error consequence indeed. Therefore, the blade vibration test is hard to complete using general test method sometimes.rnWang and Cheng developed one method ,who had used free vibration information to identify multiple order mode parameter. In the method, the generalized eigenvalue problem converted to common eigenvalue problem adoping discrete sequential data, moreover, the method was validated by numerical simulation with noise. Chen Moli took the compress blade as the research object, and made sure the free vibration containing the high-frequency mode through the mode of unloading the force suddenly, then indentified the former 8 order modes's damper within 4300Hz.Because of the requirement of identifying the multiple order modes's frequency, elimination the effect of identified mode from original data had to operate step by step, so the operation was rather complex.rn In the previous liter

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