The Design And Control Of The Transverse Magnetorheological Elastomer Isolation Bearing

The large bridge has important strategic significance in the transportation,military and social life,and its service security has been paid more and more attention.The bridge health monitoring system is based on the modern photoelectric sensing technology,large data processing and structural analysis and evaluation theory,which provides the basis and guidance for the maintenance,repair and administration of the bridge.However,the horizontal vibration of the bridge caused by wind and vehicle operation will reduce the accuracy and service life of the optical instrument in the bridge health monitoring.Therefore,effective vibration isolation measures must be taken.The parameters of the traditional passive vibration isolation system are fixed,and cannot be adjusted according to the external excitation.Therefore,based on the vibration isolation requirements of optical instruments in bridge monitoring,this paper presents the design and manufacture of an intelligent vibration isolation device using magnetorheological elastomers(MRE).By adjusting the stiffness and damping of the MRE device in real time,the broadband and time-varying lateral excitation is suppressed,and the verification experiment is carried out.The specific work of this paper includes the following aspects:(1)The mechanical properties of the silicone rubber based MRE were tested,and a kind of transverse MRE isolation bearing was designed according to the characteristics of the material.The working principle,the design process of the mechanical structure and the simulation method of the magnetic circuit for the MRE isolation bearing were described systematically.(2)The force-displacement measurement system and the sweeping-frequency measurement system of the MRE isolation bearing were setup to study the change of effective stiffness and equivalent damping under different exciting amplitudes,different exciting frequencies and different excitation currents.Moreover,a Kelvin model was built to describe the force-displacement relationship,and prepare the transfer analysis and semi-active control of the MRE isolation bearing.(3)The thermal stability of the MRE isolation bearing was studied firstly,and the on-line temperature measurement system was designed and established.A temperature sweeping-frequency measurement system and a temperature repeated experimental system were setup to research the temperature characteristics of the bearing.The influence of temperature on its natural frequency,effective stiffness and equivalent damping was discussed deeply,and a cooling system was proposed to reduce the temperature of the MRE isolation bearing in the continuous working process.(4)A MRE isolation platform was setup by using the four MRE isolation bearings and its vibration transmission characteristics were tested.Its semi-active control condition was derived,and then the semi-active fuzzy controller was designed based on transmission characteristics of the isolation platform and the sky-hook control method.The fuzzy control simulation system was built to study controlling effect with single-frequency sine excitation and random excitation,and to prove the validity of the fuzzy control in the field of transverse vibration control.On the basis of this,a semi-active vibration isolation control system was established,which could effectively attenuate the transverse vibration in the frequency band of 8Hz to 17Hz.