Study On Vibration Reduction Of Tuned Negative-stiffness Inerter Mass Damper

In the natural environment,high-rise structures such as bridge towers and transmission towers are prone to large-scale vibration under the action of external loads such as earthquake and wind,which affect the normal use of the structure and even endanger the safety of the structure because of their special structural forms,such as light weight and small damping ratio.For such structures,tuned mass damper(TMD)is often used to control their vibration in engineering.However,in practical engineering,due to the problems of damper design,loading space and construction,the size and volume of TMD additional mass are often limited.Based on these defects in the actual engineering application of TMD,this paper proposes a tuned negative stiffness inertia mass damper(TNIMD),which combines TMD with inertia mass.The introduction of inertia and negative stiffness components into traditional TMD can not only reduce the weight of additional mass,but also expand the energy dissipation efficiency of the damper due to the existence of inertia and negative stiffness components,The damping performance of the new damper has been greatly improved.In order to analyze the damping performance of TNIMD,the single degree of freedom model is substituted for its parameter optimization design,and the corresponding optimization parameter formula is obtained to verify its damping capacity under random load.In order to analyze the damping capacity of TNIMD under multi degrees of freedom,the damping performance of a suspension bridge tower under seismic and wind loads is studied from the perspective of numerical analysis.The main work and conclusions of this paper are as follows:(1)This paper reviews the development of high-rise structures,summarizes the vibration problems of structures,and analyzes the background and significance of the topic.The development,application,advantages and disadvantages of tuned mass dampers,inertia capacitors and negative stiffness elements are summarized;(2)The negative stiffness and inertia elements are described.This paper introduces the negative stiffness from the basic concept,basic control principle and realization mechanism,and expounds that the negative stiffness assists the vibration control mainly by reducing the natural frequency of the structure.This paper introduces the basic concept and Realization Mechanism of the inertial capacity,and expounds the flexible connection mode of the inertial capacity components and the inertial efficiency enhancement.;(3)Starting from the single degree of freedom main structure,the motion equation of TNIMD main structure coupling system is analyzed,and the parameter optimization formula of TNIMD under simple harmonic load is derived by using the fixed point theory.It is found that the optimal frequency,optimal damping ratio and optimal negative stiffness coefficient of TNIMD are positively correlated with the inertia capacitance ratio,while the maximum amplitude frequency response is negatively correlated with the inertia capacitance ratio;Under the same design parameters,compared with variable tuned mass damper(VTMDI),it is found that TNIMD has a significantly better vibration reduction effect than VTMDI.The smaller the mass ratio and inertia volume ratio,the better the vibration reduction effect of TNIMD compared with VTMDI.Even under the condition of large mass ratio and inertia volume ratio,the vibration reduction effect of TNIMD compared with VTMDI has been improved by 27%;(4)By analyzing TNIMD under random load,it is found that TNIMD shows good damping performance under stationary random excitation and seismic random excitation,and has more obvious advantages than VTMDI under the same parameters.The effect of negative stiffness on damping is verified from the side;(5)Taking a suspension bridge tower as the research background,the dynamic characteristics of the bridge tower structure are analyzed,and the multi degree of freedom model is simplified.Through the modal superposition method,the responses of the bridge tower structure under various loads such as earthquake and wind are calculated.Six common seismic waves are used to load the simplified model of the bridge tower.The dynamic responses of the bridge tower under uncontrolled and TNIMD control are compared,It is considered that TNIMD has certain control effect on multi degree of freedom structures under earthquake;The Kaimal code wind spectrum is used to simulate and synthesize the fluctuating wind at each node height of the simplified structure of the bridge tower.By comparison,it is found that the simulated fluctuating wind energy is in good agreement with the Kaimal code wind spectrum.The dynamic response of the bridge tower under uncontrolled and TNIMD control is obtained by applying this fluctuating wind to the structure calculation.The results show that TNIMD has a certain control effect on the multi degree of freedom structure under wind load.