Parameter Identification Of Blade Torsional And Bending-torsional Coupling Vibration Based On Blade Tip Timing

In many important fields,the rotating blade is the core component of the function transformation of large rotating machinery,which is an important guarantee for the operating efficiency and work safety of the equipment.Under working state usually occurred under high load and vibration,thereby causing serious consequences,but at present most of the vibration measurement based on the bending vibration,torsional vibration and bending torsional coupled vibration due to measurement method is complicated,difficult parameter identification is seldom mentioned,for the blade twist and bend torsion coupling vibration research helps more realistic simulation of blade vibration state of actual work,It is a very important research direction to monitor and obtain blade vibration parameters more accurately.In this paper,the blade tip timing method with wide frequency band,low cost and strong anti-interference ability is adopted to measure vibration.For parameters identification and experiments are carried out for the measurement of torsional and bending-torsional coupling vibration of blades.The important contents are as follows:(1)The static frequency experimental platform was built to measure the natural frequency of the blade,and the finite element model of the blade was established to make the measured data identical with that of the static frequency experimental platform.Then the blade model was imported into ANSYS finite element analysis software for analysis.The multi-order modal analysis of the blade model was carried out to obtain the formation diagram of each order vibration,obtain the torsional and bending-torsional coupling vibration parameters of the blade at various rotating speeds,draw the Bell diagram of the blade,and discuss the characteristics and resonance areas of the torsional and bending-torsional coupling vibration of the blade.(2)The bending and torsional vibration were coupled into bending-torsional coupled vibration by MATLAB,and the simulation model and vibration measurement model were established.The parameters of torsional and bending-torsional coupled vibration were identified by the designed parameter identification algorithm.The identification results and simulation results were analyzed and compared together to verify the feasibility and parameter identification accuracy of the torsional and bending-torsional coupling vibration parameter identification algorithm,which proved that the identification algorithm could effectively identify the parameters of the blade vibration measurement experiment.(3)Processing sensor fixed bracket to the original single tip timing sensor into multiple columns tip timing sensor,the reconstruction of the laboratory bench experiment,measurement of blade bending and torsional vibration parameter,get the blade vibration displacement,the parameter identification algorithm is applied to the experimental results with finite element analyzes and compares the simulation results verify the accuracy of parameter identification algorithm.