Research On The Vibration Control Of Passive Adaptive Suspension Mass Pendulum

High-rise structures are more sensitive to extreme effects such as wind loads and earthquakes,and are prone to fatigue damage,thus affecting the safety and service functions of the structures.Therefore,it is very necessary to control the vibration of high-rise structures.Suspended mass pendulum as a passive vibration reduction system,it has many advantages such as obvious vibration reduction,simple design,high reliability,easy installation and so on,has been widely used in practical projects.However,the problem of large swing angle frequency detuning due to the large dynamic response of the main structure will reduce the vibration suppression performance of suspended mass pendulum.Most of the current adaptive suspended mass pendulum vibration reduction systems are adjusted by sensors and actuators.Although the effect of its vibration reduction is good,it needs precise electromechanical and sensing system,which is usually expensive to maintain,also its reliability and stability are difficult to guarantee in practical large civil engineering.The damage of some electronic components in harsh environment may cause the vibration reduction system to fail to work properly.In this paper,the passive adaptive suspended mass pendulum vibration reduction system will be studied,which can avoid the use of actuators and sensors,more easily implemented in the project with low cost and good reliability,only by designing the support to change the effective swing length,so as to achieve the purpose of adaptive vibration reduction.(1)Considering the large swing angle non-linearity of suspended mass pendulum,the mathematical equation of arc-shaped support which can keep the period of suspension pendulum constant in large swing angle vibration is derived,and the vibration suppression performance of suspended mass pendulum is improved.Taking a single-degree-of-freedom system as an example,the equation of motion is established and solved by Lagrange equation.Finally,the influence of parameters such as pendulum length and mass ratio on the vibration suppression performance of adaptive pendulum is studied through parameter analysis.(2)Taking a high-rise structure as an example,the three-dimensional finite element model of a high-rise structure is established by using SAP2000 software.Then the sinusoidal excitation is input to calculate and compare the dynamic response,of the structure-pendulum system under the control of uncontrolled,traditional pendulum and adaptive pendulum respectively to verify the effectiveness of the adaptive suspended mass pendulum.Finally,8 different seismic waves under four site types are selected,and the seismic intensity and site type are analyzed to analyze the relationship between traditional p and seismic intensity.(3)Making a two-story frame model and taking the vibrating platform for the vibration suppression effect of adaptive suspended mass pendulum system.Using vibrating platform to apply different sine excitation and earthquake excitation as the test model.By comparing the dynamic response at the top of the structure under the control of uncontrolled and adaptive pendulum,to analysis the vibration suppression effect of the additional pendulum and the adaptive pendulum.Then verify the rationality and effectiveness of the adaptive pendulum proposed in this paper.