Study On Cable Vibration

The vibration behavior of inclined cable is studied in this thesis. Inclined cable are most easily prone to exhibit vibration of large amplitude that may be excited by environmental excitation. Because of the small mass, large flexibility and small damping, fatigue failure and large economic loss may occur due to change of destroyed inclined cables. On the other hand, the vibration of large amplitude can also make passers-by worry about the safety of the bridge. So the study of cable vibration mechanism has important engineering significance.The calculation theories of cable vibration are also introduced in the thesis. Taking into account the effect of the chord component of the gravity in the nonlinear vibration of cables,the nonlinear equations of motion for an inclined cable are developed. Galerkin’s method is used to convert the nonlinear partial differential equations into ordinary differential equations. The approximate solution of the equations is obtained with perturbation method. Develop the corresponding numerical method, and compile the computer program for solving nonlinear differential equations. A more precise function is chosen to approximate the catenary sag.A program about the cable vibration is developed under windows system. The basic methods of the program design about Finite Element Method using object-oriented programming is explored. In the windows program, a great many truss elements is used to represent a cable, and structural object is designed with the inheritance mechanismThe dynamic response of a cable-stayed bridge is analyzed with the time history method, in order to make preparation for the local dynamic analysis of the inclined cable. The acceleration process of its key points under seismic waves is recorded.The finite element program Ansys will be applied to establish a finite element spatial analysis model of a inclined cable of the cable-stayed bridge. Taking the key points’ acceleration schedule of the overall analysis as input parameters, the time-history analysis of the inclined cable is made with the high-mass method in the Ansys.