The Vibration Characteristics Test And Analysis Of An Aero-engine Turbine Blade

As a major part of an aero-engine, the vibration failure of a blade may affect the reliability of the whole aero-engine. Hence, it's of great importance to study the vibration characteristics of blades. In this thesis, a specified aero-engine turbine blade is taken as a research object, whose vibration characteristics are tested and analyzed by using vibration table resonance method, hammering method and the finite element method in ANSYS software respectively. The main research contents are as follows:(1) A blade vibration characteristics test system based on the vibration table resonance method was built. According to the test system, the blade was excited by the electromagnetic vibration table. Then the stress distribution of the blade could be obtained by strain gauges; the first three order frequencies were tested by non-contact eddy current sensors; and the first three order modal shapes were described by using throwing sand method. Finally the influence factors of the blade's natural frequencies and vibration stresses were discussed.(2) The modal analysis test of the aero-engine turbine blade was done based on hammering method. The basic principles of the test were described in this part. Besides, more details about the inspected point planning, parameters setting, sensor installation, transfer function incentives and modal identification during the test were introduced. The test results were consistent with the results by using vibration table resonance method, which verified the modal analysis test process.(3) A 3D entity model of the aero-engine turbine blade was established based on Solidworks software, which was imported into ANSYS software to build the finite element model by finite element meshing. Then the inherent characteristics were solved by defining the boundary conditions according to the actual clamping state of the blade. The finite element model was verified by comparing the finite element analysis results with the test results through the above two methods. Finally the dynamic frequency analysis of the blade was done by combining with the working condition of the aero-engine. The analysis results were helpful for avoiding the blade resonant vibration.(4) By comparing with the test and analysis results through the above three methods, the advantages and disadvantages of each method were discussed. For the hammering method, its calculation speed was high. However, there could be some deviation in the modal shape. And it's unable to test the stress distribution of the blade. In terms of the vibration table resonance method, it not only had the advantages of high efficiency and stable test results, but also had the disadvantages of long preparation time. This method was suitable for the frequency test of blades in enterprise production. According to the finite element analysis method in ANSYS software, there were some difference between the analysis results and the test results, which were within the allowable range. Moreover, the dynamic model of the blade could be predicted. The time and cost could be saved as well. Therefore, the vibration table resonance method and the finite element method in ANSYS software can be combined to analysis the aero-engine turbine blade in this thesis. The results will provide scientific basis for the optimization design, vibration safety inspection and vibration characteristics test technology of the blade.