Research Of Rotor’s Dynamic Fault Characteristics For Full Vector Spectrum Analysis

The structure parameters (such as stiffness and damping) and eccentric mass (external excitation) of rotor systems have great effect on dynamic characteristics. The fault diagnosis process, which is based on vibration detection, is to analyze the possible change of stiffness, damping and drive according to dynamic response characteristic of rotor system. Full vector spectrum (FVS) is the practical technology that describes dynamic response of rotor-bearing system objectively using information fusion method. Characteristic parameters of FVS can be a basis for fault diagnosis of rotor systems. So it has very important significance that analyzing and establishing the relation between dynamic parameters (such as brace stiffness) of rotor system and FVS parameters (such as main vibration vectors, eccentricity and vibration vector angle) according to rotor dynamics and FVS theory.Support components of most rotating machinery are anisotropic. That is to say different directions of support components have different stiffness or damping. In this paper, the finite element model of rotor-bearing system is built in order to analyze the distribution of stiffness, damping and eccentric mass in horizontal and vertical directions. Numerical simulation is applied using finite element method. Then the experiment is performed to check the results by rotor test-bed.The relation between stiffness in horizontal and vertical directions and FVS parameters is analyzed. The result shows that main vibration vectors, assistant vibration vectors and azimuth will change with the stiffness in perpendicular direction under a constant speed. It is checked by experiment. The fault distinguishing which according to eccentricity is presented. The installation principle for sensors is given according to the result. So the veracity of fault monitoring for rotor system can be improved.The relation between bearing damping and FVS parameters is analyzed by finite element method. It shows that damping has effect on main vibration vectors, assistant vibration vectors and azimuth. Because of the damping, vibratory quantity of rotor system the same as vibration vector value and eccentricity reduces. So the bearing damping restrains the vibration.The relation between eccentric mass and FVS parameters is analyzed. It shows that eccentric mass only has effect on main vibration vectors and assistant vibration vectors, not the eccentricity and vibration vector angle. That is to say eccentric mass only affects size of axis motion trajectory not the shape or position.The relation between rotor system parameters and FVS parameters which is analyzed in this paper can be used in fault mechanism research of rotating machinery. So it can improve the veracity of fault diagnoses.