Research On The Characteristics Of Torsional Vibration And The Loss Of Fatigue Life Of Flange Coupling

In this paper,the dynamic characteristics and fatigue life loss of low-pressure cylinder-generator coupling near the dangerous cross-section in the torsional vibration fault of turbo-generator are studied.Firstly,researchfor the contact theory and contact type of non-linear contact and the solution algorithm,expounded the principle and process of discretization of three-dimensional solid model by finite element method;The finite element model of bolted joint and surface unit is established intheory;the three-dimensional model is established by using SolidWorks,and the finite element software workbench is used toestablish thecontactpair.It is defined that the contact type between the circumferential surface of the stud and the pair of wheels and the gear wheel of the steering wheel is frictional and the friction coefficient is set to 0.15;the contact type between the two pairs of wheels and the gear wheel of the steering wheel is frictional and the friction coefficient is 0.15;The type of contact with the tread is bonded.The type of contact between the nut and the tread is bonded,anda total of 122 pairs of contact pairs are provided.By setting different boundary conditions,the paper analyze the static state of the low-pressure cylinder-generator coupling by finite element method,.Through the finite element simulation,the relationship between the coupling torque and the stress value of the positionofbolt central screw?contact surface near the outer edge of the coupling areaof the gas side of the screw and the contact surfacewhere bolt surface gear wheel and two pairs of wheels was obtained.Onthe basis oft here search,the relationship curve was drawn by fitting and,the s-n curve was established by using the three parameter power function model.Combined with the rain flow method and Massion-coffin formula and miner theory,the cumulative fatigue life loss of the dangerous parts of the couplingis calculated.