Study On The Design Of New Clutch Inerter Devices And The Seismic Mitigation Performance Of Structures With New Clutch Inerter Devices

The vibration of civil engineering structures seriously endangers the safety of buildings.Optimizing the seismic performance of buildings only through traditional structural parameter design has gradually shown local limitations.Therefore,many domestic and foreign scholars began to focus on the research of vibration control.In the classification of vibration control,passive control without external energy input can realize the consumption or transfer of vibration energy by setting vibration damping and isolation devices,and is widely used because of its advantages of simple structure and easy maintenance.In recent years,a new type of energy dissipation and damping device-inerter has emerged in the field of passive control.Relying on the special performance of storing inertia under the force at both ends,the inerter breaks through the mass limit of the material itself,provides a virtual"mass"for the installation structure,and realizes the control effect of vibration damping for the structure by transferring and consuming part of the vibration energy.After the painstaking research and experimental analysis of scholars from all walks of life in recent years,there are many types of inerters proposed at present,but there are also some defects focusing on the mechanical structure and operation state of various inerters.The controllable range of inertance is generally limited and bound by materials and dimensions.From the application direction of inerter,most of the relevant research and application are also concentrated in the field of machinery and transportation,and the vibration reduction control for civil structures is still in the preliminary stage.Therefore,it is necessary to pay more attention to the device designt and performance research of inerter.The design of the new inerter devices carried out in this paper are mainly based on the gear and rack transmission mechanism and the idealized clutch inerter(CID)concept.It aims to develop a high-efficiency inerter device with excellent performance combined with the high-efficiency function of mechanical design and the flexible structure of electromechanical control.The research work completed in this paper mainly includes the following aspects:(1)The semi closed inerter devices of clutch inerter(CID)and clutch inerter with reducer(RCID)are designed.The motion equations of the two new inerter devices are derived in detail by considering the rotation angle relationship and additional rotation damping in the effective stage of the device.Under the input of a series of harmonics and two kinds of seismic waves,the shaking table experiments of CID and RCID devices are carried out,the dynamic performance of the two inerter devices about excitation amplitude,excitation frequency and actual inertance is analyzed,and the difference of vibration reduction effect between the two devices is compared.According to the force,energy change and hysteretic performance of different devices,the relevant mechanism analysis is given.Based on the data analysis of flywheel speed and additional rotational damping,the relevant change laws are summarized.The comparison of dynamic test results shows that the inertance of inerter can be effectively improved by increasing flywheel and installing reducer.When the reduction ratio is n:1,the inertance of RCID under low-frequency sinusoidal excitation can be increased to n~2 times of CID,and the speed and additional rotational damping of flywheel under sinusoidal excitation can be increased to n times.Finally,through the comparison between numerical simulation models and experiments,the theoretical model and relevant conclusions of inerter devices are verified.(2)Based on the basic structure of mechanical inerter,electromechanical inerters of energy consuming(ECID)and energy harvesting(EH＿ECID)are designed.With the help of electronic pulse switch controlled by d SPACE in real-time,the energy consuming electromechanical inerter is divided into all damping electromechanical inerter and partial damping electromechanical inerter.Through the theoretical derivation of electric damping and electric inertia,the motion models of several electromechanical inerters are established in turn.The shaking table experiments of electromechanical inerter devices are carried out under the same loading conditions and parameter settings as mechanical inerter experiments.The differences of force,flywheel speed and rotational damping between the all damping inerter and partial damping inerters are analyzed.In addition,the relationship between flywheel speed and motor output voltage and the change of rotation damping superimposed by motor and flywheel are studied in turn.Based on the vibration reduction performance of mechanical and electromechanical inerter,the advantages and new characteristics of electromechanical inerter are highlighted.Through the application of electric damping and electric inertia,the inertance and flywheel deceleration efficiency can be effectively improved.The subsequent numerical simulation comparison also verifies the reliability of the models and conclusions.(3)According to the failure forms of gear,the material parameter suggestions and strength design method of gear and rack in the new inerter device are described.Taking the experiment device in Chapter 2 as an example,the strength of gear and rack is checked and calculated.In order to verify the accuracy of the check section and understand the failure mode of gear and rack meshing transmission process in detail,ABAQUS finite element numerical simulation analysis is carried out.According to the simulation results,the maximum bending stress,contact stress and logarithmic strain of gear and rack are summarized in meshing transmission,and the element,node and surface positions of gear failure are determined.The failure section and failure mode in strength checking calculation are verified.Finally,through comprehensive analysis,the design suggestions of gear and rack of the new inerters are given.(4)Using the energy method of seismic strength analysis,the energy composition simulation calculation of single degree of freedom structures of inertial mass damper(IMD)and three kinds of clutch inerters(ideal,all damping and partial damping)is carried out under seismic load,a series of energy indexes are defined,and the distribution law and relationship of energy in each part of the structure are obtained.Through the numerical simulation analysis of multiple groups of parameters,the effects of additional rotational damping and inertia mass ratio are explored on structural displacement,and the displacement reduction effects of several inerter structures are compared,which shows that the clutch inerter has good vibration reduction ability.Taking the total input energy and invalid damping energy as the measurement indexes of vibration reduction control,the two key control parameters of additional rotational damping and inertia mass ratio are optimized.The optimal value should be the zero point of change rate on the relevant energy curve,the maximum value and critical value in special cases.The optimization results are also verified by the structural displacement.Finally,using the equivalent linear method of ideal CID,the analytical solutions of steady-state displacement,total input energy and optimal inertia mass ratio index under harmonic excitation are derived,and their effectiveness is verified by numerical simulation.(5)Based on the new inerter devices proposed in this paper,the single degree of freedom structural motion equations of the new inerters are established.Under the input of a series of harmonics and two kinds of seismic waves,taking the uncontrolled structure and the single degree of freedom system with ideal CID as the control model,the dynamic experiments of the single degree of freedom structure are carried out,and the basic parameter identification tests of the uncontrolled structure are carried out.Based on the results,the vibration reduction effects of several inerter structures are compared,and the correlation analysis is made from the inerter mechanism.The two degree of freedom structure examples of the new inerters are supplemented,and the effects of friction and gear backlash are considered in detail,and the multiple nonlinear models of CID and RCID are analyzed.The subsequent numerical simulation results are in good agreement with the experimental data,which shows that the clutch inerter with reducer and electromechanical inerter have superior vibration reduction performance.