| With the rapid development of China's economy,large-span cable-stayed bridge has been built in large numbers.The cable-stayed cable is an important component of the structure,which plays a vital role in bridge safety.At present,the research shows that the special structure of cable,such as damping small,large sag,and small stiffness,can cause great vibration and fatigue damage in the external load,so it is very important to study the vibration reduction of cable stayed cable.At present there are three methods for passive control of cable,including aerodynamic measures,structural measures and mechanical damping measures,in which the most widely used viscous dampers,but a lot of practice shows that: the general structure of the viscous dampers are usually installed in The vibration displacement of the control cable is small,and it is connected with the bridge beam.The resonance effect is very easy under the action of external load,and its vibration reduction effect is much lower than the theoretical value.Tuned Mass Damper(TMD),which is not affected by the installation position,can overcome the above shortcomings of the general mechanical dampers,but the tuned mass dampers of the general structure are due to their own gravity problems,The control effect is not very satisfactory.This paper presents a new uned mass damper with elliptical thin-walled structure t for bridge cable vibration control.The damper is composed of a plurality of elliptical thin-walled structures.This structure is theoretically simple,needs no external equipment control,has a simple structure for easy installation and requires low maintenance costs,and the device can bear its own weight,so it can be easily used for large span Vibration control of bridge cable-stayed cable and tie-bar.The contents of this paper include the following aspects:(1)Study single elliptical thin-walled structures mechanical properties.By means of finite element software,the mechanical properties of single elliptical thin-walled structures with different design parameters were analyzed by parametric modeling.The simplified mechanical model of single elliptical thin-walled structures was established by fitting the finite element software.The relationship between the maximum yield range and the parameters is obtained,and the coupling effect of the horizontal and vertical stress directions of the single elliptical thin-wall structure is analyzed.In addition,the approximate calculation method of the relationship between the force and deformation of a single elliptical thin-walled structure is studied by energy method,and the effectiveness of the method is verified by numerical simulation(2)Study on Mechanical Properties of the Whole Tuned Mass Dampers.A plurality of elliptical thin-walled structures are organically combined to form a tuned mass damper for cable vibration control.The relationship between the force and deformation of the whole dampers is studied by the geometrical correlation of the elliptical thin-walled structures and the mechanical properties of their own forces and deformation.The mechanical model of the whole dampers is established.The results show that the dampers have different mechanical forces Performance changes little,can be used for cable multi-directional vibration control(3)Research on Cable Vibration Control Based on New Type Damper.In this chapter,the damping effect of the tuned mass damper is studied from the finite element model and the simplified model considering the bending stiffness and sag of the cable.The method of time-history analysis was used to solve the damping effect of the cable-TMD system under random wind load.The nonlinear TMD was linearized by the appropriate method.And verify its feasibility.The results show that the vibration effect is equivalent to that of the original nonlinear structure in the range of acceptable error.The simulation results show that the elliptical thin-walled structure tuned mass damper designed in this paper has a good effect on the cable-stayed cable. |
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