Rotor Dynamics Analysis With Consideration Of The Modulus Deterioration

Rotating machinery is widely used in industrial and agricultural production.It is an extremely important power equipment.Rotor failure will lead to great economic loss,touch the ground is a type of rotor system fault,rotor bump grinding happenwhen relative offset in the center of the trunnion axis and the bearing exceed clearance,the elastic modulus degradation of the rotor shaft increases unbalance response of the rotor system,namely the offset increasing.Therefore,based on the degradation of elastic modulus,this paper studies the influence of elastic modulusdegradation on the unbalance response,rotor vibration model and critical speed of rotor bearing system.The main contents of this paper are:Firstly,Choosing medium carbon steel specimen in elastic modulus degradation experiments to test,we can obtain hysteresis degradation curve diagram and the elastic modulusunder different stress conditions by analysisanalyzingthe test data.We get the degradated elastic modulus model has to do with the loading frequency and stress by McQuart method.Secondly,The elastic shaft of the rotor is simplified to be the Euler-Bernoulli beam,and we can use the method of form function method to get the the maximum stress of the euler beam,which is used to solve the maximum stress of the rotor shaft at work.Through finite element method to establish the dynamics equation of the rotor-bearing system,combined with elastic modulus degradation model and the axial period of maximum stress formula,we apply the dynamic modulus of elasticity for the rotor system dynamics integral equation of motion.Then we study the influence of the elastic modulus of degradation on rotor unbalance response amplitude,the critical speed and vibration mode.Thirdly,In a rotor system as an example,using the Latin hypercube sampling,using the response surface method fitting system response and the function relation between the random variable parameters,and then using mean a second moment method,calculation and analysis the reliability of the rotor system don’t happen to touch the ground and the reliability sensitivity of the stochastic parameters.Through the above research work,combining the model of elastic modulus deterioration with the maximum stress formula,we find that the deterioration of elastic modulus will increase the unbalanced response of the rotor system,and the critical speed of the rotor system will also deteriorate increase with the deterioration rate ratio,at the same time,the deterioration of elastic modulus also increases the possibility of the rotor system rubbing occurs.Therefore,this study will provide some guidance for analyzing the influence of the elastic modulus’ deterioration on the mechanical properties of the rotor.