Integrated design method of MR damper and electromagnetic induction system for structural control

Abstract

Magnetorheological (MR) dampers are one of the most advantageous control devices for civil engineering applications to natural hazard mitigation due to many good features such as small power requirement, reliability, and low price to manufacture. To reduce the responses of a structural system by using MR dampers, a control system including a power supply, control algorithm, and sensors is needed. The control system becomes complex, however, when a lot of MR dampers are applied to large-scale civil structures, such as cable-stayed bridges and high-rise buildings. Thus, it is difficult to install and/or maintain the MR damper-based control system. To overcome the above difficulties, a smart passive system was proposed, which is based on an MR damper system. The smart passive system consists of an MR damper and an electromagnetic induction (EMI) system that uses a permanent magnet and a coil. According to the Faraday law of induction, the EMI system that is attached to the MR damper can produce electric energy and the produced energy is applied to the MR damper to vary the damping characteristics of the damper. Thus, the smart passive system does not require any power at all. Besides the output of electric energy is proportional to input loads such as earthquakes, which means the smart passive system has adaptability by itself without any controller or sensors. In this paper, the integrated design method of a large-scale MR damper and Electromagnetic Induction (EMI) system is presented. Since the force of an MR damper is controllable by altering the input current generated from an EMI part, it is necessary to design an MR damper and an EMI part simultaneously. To do this, design parameters of an EMI part consisting of permanent magnet and coil as well as those of an MR damper consisting of a hydraulic-type cylinder and a magnetic circuit that controls the magnetic flux density in a fluid-flow path are considered in the integrated design procedure. As an example, a smart passive control system for reducing stay cable responses is considered in this investigation and it will be fabricated and tested through experiment in the future.

Design, performance test and analysis on magnetorheological damper for earthquake mitigation

“…The total damping force F produced by the MR damper contains a controllable damping force F τ , a plastic viscous force F η and a friction force F f . …”

“…Lee et al . has studied the integrated design method of a large‐scale MR damper and electromagnetic induction system and has also considered a smart passive control system for reducing stay cable responses in this investigation. Considering that most MR dampers have annular magnetically active area, Chooi et al .…”

A Novel Hydraulic Actuation System Utilizing Magnetorheological Fluids for Single-Port Laparoscopic Surgery Applications

“…When activated, the developed MR actuators should provide sufficient locking forces, through which the posture of the SLS tool should be maintained during SLS procedures. Since the designed MR actuator works under the shear mode, the total locking force (F t ) provided by the MR damper is equivalent to the sum of the magnetic field-dependent damping force (F τ ), the viscous damping force (F v ) and the friction force (F f ) [30,31].…”

Experimental analysis of vibration isolation using hybrid magnet and magnetorheological fluid damper

“…Nagaya et al [8] reported that the damping force varies with the magnetic field applied across the MR fluid but independent of the frequency input to the damper. Lee et al [17] discussed the conceptual design of the multistage MRF damper, and integrated design procedure for MRF damper was developed based on magnetic analysis. Sławomir et al [18] found that the response of dynamic viscosity of investigating MRF was faster to the applied external magnetic field.…”