Analysis On Nonlinear Dynamics Of Cable-beam Structure

In recent years, a new type of structural system named cable-beam structure has been put forward. The cable-beam structure is provided with straightforward load and compact form. It is widely adopted in machinofacture and civil engineering owing to the characteristics of the tensile strength of cables and compressive/bending strength of beams. Either flexible cables or elastic beams have been widely and deeply studied, both theoretically and experimentally, however the combination of them as a whole still attracts research efforts and remains an open area for contribution. The vibration of cable and beam interconnect closely, which influences the security, amenity and service life of the composite structure. Therefore, it is to the point and of great theoretical and realistic significance to study the mode and mechanisem of structural nonlinear vibrations. This thesis is a systematic research on nonlinear dynamics behavior of the cable-beam structure. The main research results obtained in this paper are as follows.1. The state of the art in research and the related knowledge of nonlinear dynamics of the cable-beam structure are introduced. In the first chapter of the paper, the reasearch of nonlinear vibration of the cable-beam structure are expounded. The major works that domestic and foreign scholars have done in the field of vibration are reviewed, and the related mechanism are briefly analyzed.2. The nonlinear free vibration of the cable-beam structure is analysed. By leveraging the most simple coupling structure, which is composed of single-cable and single-beam, as the object of the research, we establish the partial differential equations of motions of the cable-beam structure by following the Hamilton principle. Considering the special condition that three natural frequencies of the system are approximately in the ratio of 1:1:2, we work out an approximate solution to the equations by the perturbation method of multiple time scales, and get the differential equations of motion and the nonliear equations of steady state responses of internal resonance.3. The influence of the structural parameters on the motion is studied. Using the runge-kutta method, we conduct some numerical simulative studies on the influence of parameters on the motion. The parameters aforementioned include the tuning parameters, the initial disturbance, the viscous damping ratio, the angle between the cable and beam, the tensile/compressive stiffness, and the initial stress. The control methods of the nonlinear vibration of cable-beam structure have been summarized.4. The nonlinear forced vibration of the cable-beam structure is analysed. Considering the more common situation in real life, we apply the harmonic force with the same frequency to the three degrees of freedom respectively and analyse the external resonance of the system when the excitation frequency approaches the horizontal and the vertical natural frequency of the beam. The variation of the frequency and the amplitude of structure applied on the external force are studied.5. Thermally induced vibration of cable-beam structure is explored. Using the aforementioned method, this thesis makes thermal deformation equivalent elastic deformation. How the vibration of the cable-beam structure changes as the environment temperature varies are studied theoretically. Meanwhile, it discloses that the in-depth mechanism of the nonlinear vibrations of cable-beam structure is affected by the temperature.