Torsional Vibration Modal Parameters Identification And Software Realization For Rotating Machinery

With the development of technology,the working conditions of rotating machinery have been greatly changed.More and more extreme conditions are taken account,such as heavy load,high pressure,high temperature,high speed,unstable and so on.Torsional vibration of rotating machinery because of high load of rotating machinery under extreme conditions.Therefore,in order to monitor and analyze the torsional vibration of rotors,taking rotors of rotating machinery as object,the measurement of rotor torsional vibration and modal parameters identification are analyzed.The traditional torsional vibration measurement method has been improved,a double tooth torsional vibration measurement method is proposed.The correctness and reliability of the measurement are confirmed by simulation.The influence of multiple factors such as noise,bending vibration and signal trend in signal measurement are analyzed and the processing method is given.The influence of measurement error in torsional vibration measurement with double teeth method is analyzed.The corresponding relationship between the number of gear teeth and sampling frequency is given.The gear indexing error and teeth eccentricity error are analyzed,and the relative solutions are put forward.Rotor torsional vibration test bench and measurement process are designed based on double teeth method.The feasibility of the method is verified by torsional vibration test with double teeth method.Torsional vibration signals are measured by changing rotational speed and gear teeth number.Indirect estimation of natural frequency of torsional vibration by maximum angular displacement of torsional vibration.The results show that:(1)The instantaneous rotational speed of the rotor can be accurately obtained by the double-tooth method;(2)It is feasible to estimate the natural frequency of torsional vibration by extracting the maximum angular displacement of torsional vibration at different rotational speeds.The extraction of rotor instantaneous speed is studied by using time-frequency analysis algorithm.Three methods of Short-time Fourier Transforms,Wigner-Ville Distribution and Wavelet Transforms are compared.The results show that the extraction result of wavelet transforms is better.A wavelet ridge extraction method based on wavelet denoising is proposed,and the experimental signal is analyzed.The results show that the wavelet ridge extraction method based on wavelet denoising can effectively extract the instantaneous speed.The identification algorithm of torsional vibration modal parameters is studied,and the experimental data are analyzed.The results show that the identification algorithm can achieve the identification effect of torsional vibration modal parameters.According to the method of torsional vibration measurement and signal processing,a software for identifying torsional vibration modal parameters is developed based on the MATLAB platform.The software can realize the function of torsional vibration measurement and analysis of rotor.