Study On The Performance Of New Type Of Deformation-amplified Dampers And Their Vibration Control For Structures

Structural vibration control makes up for the shortcomings of traditional seismic design methods.In the field of structural vibration control,passive control is widely concerned by scholars because of its advantages of simple structure,low cost,easy maintenance and independence of external energy.The technology of energy dissipation damper is an effective method to realize structural passive control and to reduce the dynamic response of structure under earthquake and strong wind.However,for most of the building structures,due to the characteristics of the structure itself or the constraints of engineering conditions,the deformation of the damper installed in the structure is relatively small under the earthquake,and the damper can not bring its work into full play to achieve the purpose of energy dissipation.So it will be limited in practical engineering applications.Therefore,it is very necessary to study anew type of damper with the function of deformation amplification.This kind of damper is also sensitive and applicable to small deformation,and can fully drive the energy dissipation material to exert its energy-consuming characteristics so as to achieve more ideal vibration control effect.In this paper,two corresponding kinds of new-type energy dissipation dampers with deformation amplification mechanism are developed respectively based on the control of node rotational deformation and interlayer lateral displacement of building structures.The performance test and theoretical model derivation of the two dampers are carried out,and the seismic control effect of each kind of damper on the structure are studied respectively.On this basis,a vibration-reducing structure system with deformation-amplified composite dampers is established and its aseismic performance is verified.The main research contents and conclusions are as follows:(1)The performance test on rubber viscoelastic material is carried out and the effects of shear deformation,loading frequency and the number of loading cycles on its mechanical properties are comprehensively investigated.An improved mechanical model considering a variety of nonlinear factors is proposed,and the shear hysteretic behavior of the rubber viscoelastic material is numerically simulated.The simulation results are in good agreement with the experimental results,which verifies the effectiveness of the mechanical model.It also provides a theoretical and experimental basis for the selection of materials in the design of rotation-amplified damper in the following chapter.(2)In view of the rotational deformation at the joints of building structures,a new type of rotation-amplified rubber viscoelastic damper is proposed.Cyclic loading test is carried out to study the influence of the rotational deformation and loading frequency on the mechanical properties of the damper.The mechanical model of the damper is derived and then verified by numerical simulation.The seismic response analysis of a frame structure with the damper is conducted and the control effect is discussed.Results show that the control effect of the damper can be improved by 2?4 times by amplifying the angular displacement response at the beam-column joint by 2.5 times.(3)Aiming at the lateral displacement of building structures,a new type of re-centering deformation-amplified SMA(Shape Memory Alloy)damper is proposed.The mechanical properties of the damper are tested and the effects of different loading conditions on its mechanical properties are studied.The hysteretic model of the damper is established and then verified by numerical simulation.The seismic control effect of the damper on the structure and the influence of different displacement amplification coefficient on the control effect are studied.The results show that the control effect can be increased by 2?3 times when the interlayer displacement deformation is amplified by 2.5 times.In engineering applications,the recommended range for the deformation amplification coefficient of the damper is 2.0-3.0.In order to achieve the best energy dissipation effect,the parameter design criterion of the damper is proposed.(4)Based on the design philosophy of improving energy dissipation and vibration reduction,two kinds of dampers with the function of deformation amplification are installed on the structure at the same time to form a vibration-reducing structure system with deformation-amplified composite dampers.The elastic-plastic time history analysis of the structure is conducted,and the contribution of the two kinds of dampers to the vibration reduction is discussed.The results show that the aseismic ratio of the composite dampers system is basically greater than the linear sum of the two structures equipped with only one kind of damper.The performance of the two kinds of dampers is complementary,and the synergistic energy consumption effect is obvious.The ratio of the total energy consumption of the two kinds of dampers is close to 1.Each kind of damper gives full play to its advantages and the composite system effectively improves the overall seismic mitigation performance of the structure.