First,the equivalent relationship between single-degree-of-freedom structures with active variable stiffness (AVS) systems and special linear structures is established,and the equivalent additional stiffness ratio and...First,the equivalent relationship between single-degree-of-freedom structures with active variable stiffness (AVS) systems and special linear structures is established,and the equivalent additional stiffness ratio and the equivalent additional damping ratio are determined.Then,an approximate mode decomposition (AMD) method is proposed for multi-degree-of-freedom (MDOF) structures with AVS systems.The accuracy of the method is discussed and improved using revising parameters.Simulation results indicate that the AMD method is effective in estimating the maximum relative displacements and the maximum interstory drifts of MDOF structures with AVS systems.The study provides a foundation for the seismic design method of structures with AVS systems.展开更多
The theoretical study of a semi-active predictive control(SAPC) system with magnetorheological(MR) dampers to reduce the responses of seismically excited structures was presented.The SAPC scheme is based on a predicti...The theoretical study of a semi-active predictive control(SAPC) system with magnetorheological(MR) dampers to reduce the responses of seismically excited structures was presented.The SAPC scheme is based on a prediction model of the system response to obtain the control actions by minimizing an object function,which has a function of self-compensation for time delay occurring in real application.A double-ended shear mode combined with a valve mode MR damper,named MRF-04K damper,with the maximum force of 20 kN was designed and manufactured,and parameters of the Bouc-Wen hysteresis model were determined to portray the behavior of this damper.As an example,a 5-story building frame equipped with 2 MRF-04K dampers was presented to demonstrate the performance of the proposed SAPC scheme for addressing time delay and reducing the structural responses under different earthquakes.Comparison with the uncontrolled structure,the passive-off and passive-on cases indicates that both the peak and the norm values of structural responses are all clearly reduced,and the SAPC scheme has a better performance than the two passive cases.展开更多
文摘First,the equivalent relationship between single-degree-of-freedom structures with active variable stiffness (AVS) systems and special linear structures is established,and the equivalent additional stiffness ratio and the equivalent additional damping ratio are determined.Then,an approximate mode decomposition (AMD) method is proposed for multi-degree-of-freedom (MDOF) structures with AVS systems.The accuracy of the method is discussed and improved using revising parameters.Simulation results indicate that the AMD method is effective in estimating the maximum relative displacements and the maximum interstory drifts of MDOF structures with AVS systems.The study provides a foundation for the seismic design method of structures with AVS systems.
基金Projects(90815025,51178034) supported by the National Natural Science Foundation of China
文摘The theoretical study of a semi-active predictive control(SAPC) system with magnetorheological(MR) dampers to reduce the responses of seismically excited structures was presented.The SAPC scheme is based on a prediction model of the system response to obtain the control actions by minimizing an object function,which has a function of self-compensation for time delay occurring in real application.A double-ended shear mode combined with a valve mode MR damper,named MRF-04K damper,with the maximum force of 20 kN was designed and manufactured,and parameters of the Bouc-Wen hysteresis model were determined to portray the behavior of this damper.As an example,a 5-story building frame equipped with 2 MRF-04K dampers was presented to demonstrate the performance of the proposed SAPC scheme for addressing time delay and reducing the structural responses under different earthquakes.Comparison with the uncontrolled structure,the passive-off and passive-on cases indicates that both the peak and the norm values of structural responses are all clearly reduced,and the SAPC scheme has a better performance than the two passive cases.
