Vibration Reduction Design And Resonance Response Of Cable-stayed Beams Based On Time Delay

With the development of modern materials and construction technology,the bridge is developing in the direction of large span,flexibility,light weight and low damping.The cable-stayed bridge occupies a very important position in the long-span bridge due to its large main span,good stress performance,excellent seismic performance and mature construction technology.However,the stay cable has the characteristics of low damping and high flexibility,and it is easy to produce large vibration under the load of earthquake,vehicle,wind and rain.In this paper,for the cable-stayed beam structure,the internal actuator is designed at the joint of the cable and the beam,and the cable-stayed beam is damped based on the time-delay vibration damping technology to further study the nonlinear resonance response.The details are as follows:1.Nonlinear time-delay vibration reduction design of cable-stayed bridge and establishment of its nonlinear model.Based on the Hamilton variational principle,a finer nonlinear dynamic model of the cable-stayed beam structure is established.By designing an axial actuator at the coupling of cable and beam to control the vibration of the cable-stayed beam.The control strategy is based on the theory of time-delay vibration reduction,the nonlinear vibration control equation of the cable-stayed beam is established,and the Galerkin discretization is used to obtain the functional differential equation of the cable-stayed beam with feedback control.2.Research on the vibration reduction mechanism of cable-stayed beam under single-input and multi-input time-delay feedback control.The effect of the control parameter time lag and control gain on the damping effect is analyzed through a specific example.The multi-scale method theory was used to solve the nonlinear primary resonance response of the cable-stayed beam under single-input and multi-input time-delay feedback.Through theoretical analysis and numerical simulation,the effects of control gain and time delay on the vibration damping effect are studied,and the vibration damping mechanism under super / subharmonic joint resonance under different frequency excitations,different excitation effects,and different feedback control effects is further analyzed.3.The resonance response of the elastic beam under the control of moving load and time-delay feedback is studied.Based on servo actuation and time-delay technology,the multi-scale method is used to analyze the main resonance and 1/3 sub-harmonic resonance of the beam under moving load,and the nonlinear response under the action of velocity time delay feedback and acceleration time delay feedback.