Development of a novel multi-layer MRE isolator for suppression of building vibrations under seismic events

Abstract

Protecting civil engineering structures from uncontrollable events such as earthquakes while maintaining their structural integrity and serviceability is very important; this paper describes the performance of a stiffness softening magnetorheological elastomer (MRE) isolator in a scaled three storey building. In order to construct a closed-loop system, a scaled three storey building was designed and built according to the scaling laws, and then four MRE isolator prototypes were fabricated and utilised to isolate the building from the motion induced by a scaled El Centro earthquake. Fuzzy logic was used to output the current signals to the isolators, based on the real-time responses of the building floors, and then a simulation was used to evaluate the feasibility of this closed loop control system before carrying out an experimental test. The simulation and experimental results showed that the stiffness softening MRE isolator controlled by fuzzy logic could suppress structural vibration well. AbstractProtecting civil engineering structures from uncontrollable events such as earthquakes while maintaining their structural integrity and serviceability is very important; this paper describes the performance of a stiffness softening magnetorheological elastomer (MRE) isolator in a scaled three storey building. In order to construct a closed-loop system, a scaled three storey building was designed and built according to the scaling laws, and then four MRE isolator prototypes were fabricated and utilised to isolate the building from the motion induced by a scaled El Centro earthquake. Fuzzy logic was used to output the current signals to the isolators, based on the realtime responses of the building floors, and then a simulation was used to evaluate the feasibility of this closed loop control system before carrying out an experimental test. The simulation and experimental results showed that the stiffness softening MRE isolator controlled by fuzzy logic proved to suppress any structural vibration.

Vibration Control of Magnetorheological Elastomer Beam Sandwich

“…MREs, also known as a magneto-sensitive elastomer, are a class of smart materials whose stiffness and damping properties can be adaptively tuned to attenuate (reduce force/amplitude/effect) both low and high-frequency vibration. It is usually achieved by varying the magnetic flux input and in full active mode using sensors and actuators or semi-active mode [5,[10][11]. Also, MREs have an improve properties in new structural materials.…”

“…Various methods and materials have been proposed to reduce vibration. The methods are broadly classified as a passive, semi-active, or active system [1][2][3][4][5]. These methods use different materials to achieve vibration reduction.…”

“…The high frequency requires low stiffness and low damping vibration isolator while the low-frequency vibration requires high stiffness and high damping vibration isolator [1][2][3][4][5][6][7]. Magnetorheological Elastomers (MREs) are a class of smart materials whose stiffness and damping properties can be adaptively tuned to attenuate both low and high-frequency vibration [2][3]6,[8][9].…”

Magnetorheological Elastomer Stiffness Control for Tunable Vibration Isolator

“…The semi-active method is preferable due to its stability and reliability for both low and highfrequency vibrations. The high frequency requires low stiffness and low damping vibration isolator while the lowfrequency vibration requires high stiffness and high damping vibration isolator [1,2,[7][8][9][10][11].…”

A torsional MRE joint for a C-shaped robotic leg

“…On the other hand, to potentially improve energy efficiency while offering robustness closer to passively tuned devices in similar designs, semi-active materials such as MREs may be considered. It is for this reason that MRE has been widely used in adaptivetuned-vibration absorbers (ATVAs) [17][18][19][20][21][22], as well as other devices benefitting from controllable stiffness. On the far end of the spectrum in terms of stiffness variation capability, Li et al [15] designed a vibration isolator using MRE in a laminated structure capable of an increase in stiffness of up to 1630%.…”