A model to describe the hysteresis damper character of rubber material is presented in this paper. It consists of a parallel spring and damper, whose coefficients change with vibration frequencies. In order to acquire...A model to describe the hysteresis damper character of rubber material is presented in this paper. It consists of a parallel spring and damper, whose coefficients change with vibration frequencies. In order to acquire these relations, the force decomposition is carried out according to some sine vibration measurement data about nonlinear forces changing with deformations of the rubber material. The nonlinear force is decomposed into a spring force and a damper force, which are represented by a frcquency-dependent spring and damper coefficient, respectively. Repeating this step for different measurements will give different coefficients corresponding to different frequencies. Then, application of a parameter identification method will provide the requested functions over frequency. Using those formulae, as an example, the dynamic character of a hollow shaft system supported by rubber rings is analyzed and the acceleration response curve in the centroid position is calculated. Comparisons with sine vibration experiments of the real system show a maximal inaccuracy of 8. 8 %. Application of this model and procedure can simplify the modeling and analysis of mechanical systems including rubber materials.展开更多
Recur to multi-hole and better elastic characteristics of metal rubber （MR）, a new squeezed film damper with MR （SFD/MR） throttle ring installed on the end of MR and MR damping ring installed on the radial directi...Recur to multi-hole and better elastic characteristics of metal rubber （MR）, a new squeezed film damper with MR （SFD/MR） throttle ring installed on the end of MR and MR damping ring installed on the radial direction of MR is implemented. Based on the D＇alembert principle, a locomotion equation and the mathematical model of stationary response of SFD/MR system is put forward. It proves that the SFD/MR has better ability to resist unbalance loads than the traditional SFD after the stationary dynamic characteristics of the traditional SFD and the new SFD/MR are researched.展开更多
Based on the principle of Tuned Mass Damper (TMD),the test of a new quake reduction system was investigated.The main structure of the system is connected with the top floor through Laminated Rubber Bearing (LRB) to m...Based on the principle of Tuned Mass Damper (TMD),the test of a new quake reduction system was investigated.The main structure of the system is connected with the top floor through Laminated Rubber Bearing (LRB) to make up a huge TMD system suspended structure. It was shown from the test that the new TMD quake reduction system can reduce the acceleration of the top floor by more than one quarter if the parameters are chosen efficiently.Since the good effectiveness and easy availability, this system has the practical value in earth quake engineering.展开更多
Based on the principle of tuned mass damper (TMD). the method of using laminated rubber bearing (LRB) to connect TMD with structure is discussed in this paper. This is a new type of TMD system-suspended structure. To ...Based on the principle of tuned mass damper (TMD). the method of using laminated rubber bearing (LRB) to connect TMD with structure is discussed in this paper. This is a new type of TMD system-suspended structure. To test the function of quake-reduction and the possibility of application, this paper explores the suspended top floor through shaking table test. In the model test, an electro-hydraulic shaking table was used. The main structure model was a four-story steel frame structure. The block to combat the structural quake was a concrete block. LRB was used to connect the block to the main structure. In order to analyze the efficiency of TMD, the fundamental frequencies of the main structure and block of TMD were measured separately first. Then. the frequencies of the main structure with the block and without the block were compared respectively under sine and imitative quake waves. The test shows that this new-typeTMD system is effective in combating the structural quake often reducing the acceleration of the top floor by more than 25 %. Because of the easy availability of the method, it is endowed with practical feasibility.展开更多
The report summarizes the observed damage to a variety of buildings near the epicenter of the M6.8 Luding earthquake in Sichuan Province,China.They include base-isolated buildings,multi-story reinforced concrete(RC)fr...The report summarizes the observed damage to a variety of buildings near the epicenter of the M6.8 Luding earthquake in Sichuan Province,China.They include base-isolated buildings,multi-story reinforced concrete(RC)frame buildings,and masonry buildings.The near-field region is known to be tectonically highly active,and the local intensity level is the highest,that is,0.4g peak ground acceleration(PGA)for the design basis earthquake,in the Chinese zonation of seismic ground motion parameters.The extent of damage ranged from the weak-story collapse that claimed lives to the extensive nonstructural damage that suspended occupancy.The report highlights the first observation of the destruction of rubber bearings and viscous dampers in the isolation layer of Chinese seismically isolated buildings.It also features the rare observation of the brittle shear failure of RC columns in moment-resisting frames in a region of such a high seismic design requirement.Possible reasons that may have attributed to the reported damage are suggested by providing facts observed in the field.However,careful forensic analyses are needed before any conclusive judgment can be made.展开更多
文摘A model to describe the hysteresis damper character of rubber material is presented in this paper. It consists of a parallel spring and damper, whose coefficients change with vibration frequencies. In order to acquire these relations, the force decomposition is carried out according to some sine vibration measurement data about nonlinear forces changing with deformations of the rubber material. The nonlinear force is decomposed into a spring force and a damper force, which are represented by a frcquency-dependent spring and damper coefficient, respectively. Repeating this step for different measurements will give different coefficients corresponding to different frequencies. Then, application of a parameter identification method will provide the requested functions over frequency. Using those formulae, as an example, the dynamic character of a hollow shaft system supported by rubber rings is analyzed and the acceleration response curve in the centroid position is calculated. Comparisons with sine vibration experiments of the real system show a maximal inaccuracy of 8. 8 %. Application of this model and procedure can simplify the modeling and analysis of mechanical systems including rubber materials.
基金This project is supported by National Natural Science Foundation of China (No.50075017)
文摘Recur to multi-hole and better elastic characteristics of metal rubber （MR）, a new squeezed film damper with MR （SFD/MR） throttle ring installed on the end of MR and MR damping ring installed on the radial direction of MR is implemented. Based on the D＇alembert principle, a locomotion equation and the mathematical model of stationary response of SFD/MR system is put forward. It proves that the SFD/MR has better ability to resist unbalance loads than the traditional SFD after the stationary dynamic characteristics of the traditional SFD and the new SFD/MR are researched.
文摘Based on the principle of Tuned Mass Damper (TMD),the test of a new quake reduction system was investigated.The main structure of the system is connected with the top floor through Laminated Rubber Bearing (LRB) to make up a huge TMD system suspended structure. It was shown from the test that the new TMD quake reduction system can reduce the acceleration of the top floor by more than one quarter if the parameters are chosen efficiently.Since the good effectiveness and easy availability, this system has the practical value in earth quake engineering.
文摘Based on the principle of tuned mass damper (TMD). the method of using laminated rubber bearing (LRB) to connect TMD with structure is discussed in this paper. This is a new type of TMD system-suspended structure. To test the function of quake-reduction and the possibility of application, this paper explores the suspended top floor through shaking table test. In the model test, an electro-hydraulic shaking table was used. The main structure model was a four-story steel frame structure. The block to combat the structural quake was a concrete block. LRB was used to connect the block to the main structure. In order to analyze the efficiency of TMD, the fundamental frequencies of the main structure and block of TMD were measured separately first. Then. the frequencies of the main structure with the block and without the block were compared respectively under sine and imitative quake waves. The test shows that this new-typeTMD system is effective in combating the structural quake often reducing the acceleration of the top floor by more than 25 %. Because of the easy availability of the method, it is endowed with practical feasibility.
基金the Natural Science Foundation of China(52122811).
文摘The report summarizes the observed damage to a variety of buildings near the epicenter of the M6.8 Luding earthquake in Sichuan Province,China.They include base-isolated buildings,multi-story reinforced concrete(RC)frame buildings,and masonry buildings.The near-field region is known to be tectonically highly active,and the local intensity level is the highest,that is,0.4g peak ground acceleration(PGA)for the design basis earthquake,in the Chinese zonation of seismic ground motion parameters.The extent of damage ranged from the weak-story collapse that claimed lives to the extensive nonstructural damage that suspended occupancy.The report highlights the first observation of the destruction of rubber bearings and viscous dampers in the isolation layer of Chinese seismically isolated buildings.It also features the rare observation of the brittle shear failure of RC columns in moment-resisting frames in a region of such a high seismic design requirement.Possible reasons that may have attributed to the reported damage are suggested by providing facts observed in the field.However,careful forensic analyses are needed before any conclusive judgment can be made.
