Dynamic Characteristics And Performance Evaluation Of The Cracked Rotor System

The rotor system is the core component of the revolving weapon.It is easy to cause damage and failure when working in complex environment such as high temperature and high speed.The cracked rotor is the most common failure of rotor system.Once the rotor system fails,it will cause great harm to the national economy and safety.Therefore,studying the dynamic characteristics of the cracked rotor system is very important guiding significance for the application of rotor system in engineering practice.Using ABAQUS,finite element analysis software,to establish a 3D model of the cracked rotor system.According to practical application,the traditional hanged support mode is improved.Using the extended finite element method(XFEM)to simulate the crack.The appropriate cracked fracture and damage criteria are selected.The settings of grid partition,dynamic analysis and the crack growth and vibration parameters are studied.Based on the finite element model of the cracked rotor system,the dynamic characteristics of the rotor system are analyzed from gravity,high speed,crack,and crack angle.Research shows:due to the influence of gravity,the amplitude of vibration in vertical direction is larger than that in horizontal direction and the axis orbit is the regular ellipse.It is revealed that the high speed makes the system complicated nonlinear phenomenon.The change of the vibration characteristics of the rotor system caused by the existence of crack.High frequency components such as 2X and 3X are excited.The axis orbit is deformed.The vibration characteristics of the rotor system with different crack angle are summarized,and the vibration characteristics of the 45 degree cracked rotor system with the change of speed are further studied.Finally,according to the vibration response and structural modal experiments for the crack-free,30 and 45 degree cracked rotor system,the vibration characteristics of three kinds of rotor systems are discussed.The correctness and reliability of the simulation analysis conclusions of the cracked rotor system are verified.The influence laws of different crack depth,speed,temperature and eccentric mass on the dynamic characteristics of the transverse-cracked rotor system are systematically analyzed,and the performance evaluation is obtained.The results show that the change of frequency multiplication amplitude in frequency domain can be used to detect the change of the depth of the transverse crack at low speed.When the rotor speed is less than the first order critical speed,the vibration response caused by the crack plays a major role.When the speed is close to or equal to the first order critical speed,the vibration characteristics caused of the disc eccentricity is dominant and the vibration characteristics caused by the crack are covered up.With the increase of temperature,the growth trend of the amplitude of 3X in frequency domain is the most obvious and the deformation degree of the axis orbit is larger.With the increase of the eccentric mass,more fractional frequency components are excited in frequency domain.The deformation of the the axis orbit is obvious and nonlinear phenomena is gradually enchanced.