| As a world cultural heritage,museum cultural relics have important cultural,artistic and historical values,and are non-renewable.At the same time,museum cultural relics has the common characteristics of light weight and easy to float,so it is very sensitive to the response of vibration load,especially the earthquake load.The vibration isolator of floating cultural relics is the decisive factor in the preventive protection of the cultural relics.However,the research on the performance design of the "museum structure-display cabinet-isolation device-floating cultural relics" system is very rare at home and abroad.Therefore,in this paper,a kind of isolator——Rolling Friction Pendulum Isolator(RFPI)is developed for the exhibition and display of floating cultural relics in the museum,taking the safety of floating cultural relics as the research center.The research focuses on the seismic response of floating cultural relics based on RFPI isolation.The main contents of the study include the following aspects:(1)Based on the characteristics of earthquake damage of floating cultural relics,a rolling friction pendulum isolator for floating cultural relics was developed,and the dynamic analysis model of the isolator was established.Firstly,the whole process of resonant response of RFPI was deduced theoretically,and the steady state response and its isolation mechanism were analyzed emphatically.Then,the influence of radius of curved surface,weight of cultural relics and excitation characteristics on the response of RFPI system was discussed.Finally,the resonant response of the device system under horizontal and vertical coupling loads was solved by numerical method,and the effects of amplitude ratio and frequency ratio on the system response were emphatically analyzed.(2)The dynamic response and isolator efficiency of RFPI system were studied by seismic simulation shaking table test.Firstly,the horizontal acceleration conduction ratio curves of RFPI system under different cultural relics weight were obtained by inputting harmonics of different frequencies.The second chapter validates the rationality and validity of the dynamic analysis model.Then,based on the acceleration transmission ratio of the RFPI system when the harmonic excitation was input,the response model of the RFPI system with the excitation frequency was established.Finally,the influence of different types of ground motion on the response of RFPI system was analyzed,and the response model of acceleration transmission ratio,ground motion intensity and cultural relics quality under random wave excitation was established.The influence of excitation characteristics and cultural relics quality on the dynamic response of RFPI was studied.(3)The seismic response of floating cultural relics based on RFPI isolator was studied by seismic simulation shaking table test.The influence of seismic ground motion frequency spectrum,intensity,ratio of height to width of cultural relics,height of mass center and mass on seismic response were discussed,and the response model of dynamic magnification factor of floating cultural relics with different ratio of height to width was established.The performance index of RFPI isolator under different fortification intensity was obtained,and the reliable application range of the isolation device was given.(4)Based on the engineering background of a museum in Chengdu,combined with the structural vibration characteristics,cultural relics characteristics and boundary conditions of the exhibition cabinet,the RFPI characteristic parameters were designed,and the finite element simulation model of the design device was established to study the dynamic response of the design device under the action of floor wave.The rationality and validity of design parameters are discussed in order to realize the design method of "isolator-cultural relics" system,and then to popularize the application of RFPI in the earthquake protection of cultural relics in the collection. |
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