Catastrophe Failure Analysis Of Nonlinear Rotor System Based On Catastrophe Theory

This dissertation is based on the project provided by National Natural Science Fund,the project name is: Research on catastrophe failure prognosis of non-linear rotarymechanical system (50975105). Rotating machinery is widely used in modern industrialproduction. With the vigorous development of the modern industry and the improvement ofscience and technology, many different systems of rotating machinery are closely connected.The rotor is one of the core units of rotating machinery, and rotor often causes problemsbecause of different fault. Mechanical failures affect the regular work of the rotatingmachinery, cause serious consequences and irreparable loss. So the research of rotor fault isnecessary and has fundamental significance.In nonlinear rotor system，according to the law of development and characteristicsfaults can be divided into two different kinds consist of gradual fault and catastrophe fault.Catastrophe fault is a kind of frequency fault for nonlinear rotor system, which brings greatdestructive and dangerous because of its external form of unexpected features. Based on thenonlinear vibration theory and catastrophe theory, average method is used to derive thefrequency-response equation of nonlinear rotor’s rub-impact fault, and cusp catastrophe andbifurcation set of rub-impact fault are established. Then, catastrophe impact factors areidentified, and catastrophe performance development laws of rub-impact are analyzed andsystem’s catastrophe areas are divided. Finally, fourth-order Runge-Kutta method is usedfor nonlinear rotor system’s rub-impact numerical analysis. The analysis results verify thefeasibility and correctness of catastrophe performance analysis based on catastrophe theory.Again based on the nonlinear vibration theory and catastrophe theory, harmonic balancemethod is used to derive the frequency-response equation of nonlinear rotor’s aerodynamicexcitation, and cusp catastrophe and bifurcation set of aerodynamic excitation areestablished. Then, catastrophe impact factors are identified, and catastrophe performancedevelopment laws of aerodynamic excitation are analyzed and system’s catastrophe areasare divided. Results of this study provide some technical support for the catastrophe fault’sdescription and prevention for rotating mechanical system.