| The reinforced concrete frame structure is widely used in residences,office buildings,industrial plants and other buildings due to its advantages of clear transmission path,simple construction,and light weight.However,many destructive earthquakes have occurred in recent years,and a large number of reinforced concrete frame structures have collapsed,causing huge casualties.The corresponding regulations in our country still have some limitations on the design method of reinforced concrete frame structures.How to make reinforced concrete frame structures have better seismic performance,The introduction and research of structural vibration control technology will be very meaningful.Nonlinear energy sink(NES)is a tuned mass damper in structural vibration control technology.It has a wide vibration absorption band and uses its own motion to dissipate seismic energy,thereby improving the seismic performance of the structure.Based on the principle of NES damping,this paper systematically completed the earthquake simulation shaking table test of RC frame structure with NES damping between layers,in order to provide favorable data reference and technical support for the application of damping technology engineering.The research contents of this paper include:In this paper,a novel NES nonlinear tuned mass damper was designed first,and the NES dynamic equilibrium equation was established.The mechanical properties and the damping mechanism were described.The relevant parameters of the NES damping system,such as optimal mass,frequency and stiffness were determined.According to the seismic simulation of the similarity rate,the shaking table test was carried out.The scaled model of the five-story RC frame structure was established according to the ratio of 1:4.The NES layout scheme and the model test loading system were determined.Through dynamical time history analysis under octave moderate and octave earthquakes,the dynamic response,displacement response and structural damage of the structure under three different NES layouts were obtained.The results were compared and analyzed.The law of seismic response of the NES structure with and without NES installed in the same magnitude was further obtained.Finally,the correctness of the software was verified by ABAQUS finite element simulation.When two-layer and four-layer shock absorbers are installed,the top X-axis acceleration peak value is reduced by a maximum of 40%,the Y-direction acceleration peak value is reduced by a maximum of 28.6%%,the three-layer X-direction acceleration peak value is reduced by a maximum of 25.0%,and the three-layer Y-direction acceleration The peak value decreases by a maximum of 28.6%,and the displacement of the top layer with respect to the X-direction of the mesa decreases by a maximum of 47.5%;When four-layer and five-layer shock absorbers are installed,the top X-axis acceleration peak decreases by 43.9%,the Y-axis acceleration peak decreases by a maximum of 47.3%,the three-layer X-axis acceleration peak decreases by a maximum of 32.5%,and the three-layer Y-direction acceleration peaks.The maximum decrease is 35.7%,and the displacement of the top layer relative to the tabletop in the X direction is reduced by a maximum of 46.3%;Second,the installation position of the NES in the same layer does not affect the damping effect,but the higher the number of installed layers,the better the shock absorption effect.In this paper,according to the 7-degree fortification intensity design,NES can be used to achieve significant shock-washing effect under octave-middle shock and octave-shock,so the RC frame structure can reduce the 1-1.5 degree fortification intensity to design and reduce the project cost.The results show that the establishment of NES damping system greatly reduces the seismic response of structures under large earthquakes. |
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