Research Of Dynamical Behavior And Characteristic Of Phase Space Fused For Rub-impact Rotor System

Rub-impact fault of rotor system is seriously non-linear phenomenon, and it shows strong nonlinear dynamical behavior. With the increasing of rotation speed and load as well as the use of new type material for rotor system, its nonlinearity is outstanding and shows chaotic characteristic. Complicated vibration phenomenon could be idetified in theory and experiment, and nonlinear rule could be understood, which plays an important part in design, use, and fault diganosis for rotor system.Rub-impact rotor is regarded as the primary research object in this paper, and from two aspects nonlinear characteristic of rotor system is analyzed. Firstly, nonlinear dynamic behavior of rub-impact rotor system is analyzed based nonlinear rotor dynamic theory. Secondly, chaotic characteristic parameters are extracted from the experiment data of rub-impact rotor based on technology of phase space fused. Summarily speaking, the detailed research content based on problem above is as follows:1.The establishment of nonlinear dynamical model for rub-impact rotor system. Considering the effect of nonlinear film force, nonlinear stiffness and nonlinear friction force, a nonlinear dynamical differential equation of rotor system with non-symmetry film force.2.The research of nonlinear dynamical behavior for rub-impact rotor system. The complicated dynamical behavior of rub-impact rotor system is researched by numerical analysis method. The evolutive rule of chaotic motion for rub-impact rotor system is comprehensively analyzed by bifurcation diagram, Poicnare section diagram, time domain wave diagram, axle center trail, phase diagram and frequency spectrum diagram. In addition, the effect of some system parameters (rotation speed, eccentricity, nonlinear stiffness ratio, stator stiffness and speed effect factor) on bifuration and chaotic behavior is principally researched. The analysis results show the effect of non-symmetry film force, nonlinear stiffness and nonlinear friction force on dynamical behavior of rotor system has serious smething with rotation speed.3.The research of phase space reconstruction parameters for rub-impact rotor system. As for the subjectivity and computation in determination of embedding dimension, a new method of embedding dimension determined by the number of intrinsic mode functions is presented. The physics meaning of this method is clear, and its computation process is simple. Above all, this method dosen't need prescient knowledge, and delay time dosen't affect the computation precision of embedding dimension.4.The research of phase space reconstruction for rub-impact rotor system. Through the analysis of chaotic attractor of univariate time series, the information reconstructed from univariate time series is imperfect, which is the abuse of phase space reconstruction from univariate time series. Then the method of phase space reconstruction based on Bayes estimate theory is presented. As for the difference between attractor reconstruted from univariate and the one reconstructed from multivariate, this method combine phase space reconstruction with data fusion, and the phase points of any univariate is fused in phase space by Bayes estimate theory, then, a new phase space fused could be obtained. And this method is applied to typical chaotic system and rub-impact rotor system, then the analysis results show the information reconstructed from multivariate includes the main characters of all univariate and represents the comprehensive information of system attractor, which makes phase space reconstructed more abundant.5.The research of chaotic characteristic extraction method for rub-impact rotor system. To ensure the integrality of fault information, maximum Lyapunov exponent and correlation dimension could be extracted in phase space fused. The analysis results show maximum Lyapunov exponent and correlation dimension for multivariate time series based phase point fused is more true and accurate. The typical chaotic system simulation of maximum Lyapunov exponent and correlation dimension and the fault diagnosis of three typical fault for rub-impact rotor system show maximum Lyapunov exponent and correlation dimension is effective in fault diagnosis.6.The experiment research of rub-impact rotor system. Auocal rub-impact equipment of rotor system is designed. Three typical fault (oil film instability, rub-impact and coupled fault) data are obtained from RK4 rotor experiment-bed.