High damping natural rubber seismic isolators

Fuller, K. N. G.; Gough, Julia; Pond, T.J.; Ahmadi, Hamid

doi:10.1002/stc.4300040202

Cited by 25 publications

(15 citation statements)

References 1 publication

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“…The multilayered MRE structure incorporates a traditional laminated rubber bearing [27][28] that consists of multiple layers of thin MRE sheets and thin steel plates. The inner steel plates give the required vertical load capacity and stiffness, while the MRE sheets offer horizontal flexibility which can be varied instantly under an applied magnetic field.…”

Section: Design and Fabrication 21 Fabrication Of A Multilayered Mrementioning

confidence: 99%

A novel magnetorheological elastomer isolator with negative changing stiffness for vibration reduction

Yang

Sun

et al. 2014

Smart Mater. Struct.

119

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Magneto-rheological elastomers (MREs) have attracted notable credits in the development of smart isolators and absorbers due to their controllable stiffness and damping properties. For the purpose of mitigating unwanted structural and/or machinery vibrations, the traditional MRE-based isolators have been generally proven effective because the MR effect can increase the stiffness when the magnetic field is strengthened. This study presents a novel MRE isolator that experienced reduced stiffness when the applied current was increased. This innovative work was accomplished by applying a hybrid magnet (electromagnet and permanent magnets) onto a multilayered MRE structure. To characterise this negative changing stiffness concept, a multilayered MRE isolator with a hybrid magnet was first designed, fabricated and then tested to measure its properties. An obvious reduction of the effective stiffness and natural frequency of the proposed MRE isolator occurred when the current was continuously adjusted. This device could also work as a conventional MRE isolator as its effective stiffness and natural frequency also increased when a negative current was applied. Further testing was carried out on a one-degree-of-freedom system to assess how effectively this device could isolate vibration. In this experiment, two cases were considered; in each case, the vibration of the primary system was obviously attenuated under ON-OFF control logic, thus demonstrating the feasibility of this novel design as an alternative adaptive vibration isolator.

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Section: Design and Fabrication 21 Fabrication Of A Multilayered Mrementioning

confidence: 99%

A novel magnetorheological elastomer isolator with negative changing stiffness for vibration reduction

Yang

Sun

et al. 2014

Smart Mater. Struct.

119

View full text Add to dashboard Cite

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“…(1) F y= = Cy ((1 − κ)zy + κuy ) (2) and the hysteretic variables zx and zy evolve according to the Park-Wen-Ang (1986) equations and the equations of motion are:…”

Section: Bi-axial Inelastic Transient Response Simulationmentioning

confidence: 99%

Performance of the Base-Isolated Christchurch Women's Hospital in the September 4, 2010, Darfield Earthquake and the February 22, 2011, Christchurch Earthquake

Gavin

Nigbor

2012

20th Analysis and Computation Specialty Conference

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The Christchurch Women's Hospital, completed in March 2005, is the only base-isolated building in the South Island of New Zealand. The displacement capacity of the base-isolation system and the super-structure ductility capacity are designed to meet 2000-year return-period demands. Detailed structural evaluations after the 2010 Darfield Earthquake and the 2011 Christchurch Earthquake revealed damage only to sacrificial non-structural components at the seismic gaps. Because the structure was not instrumented at the time of these earthquakes, basic design information, ground motion records from nearby sites, and first-hand accounts of the motion in the structure are used to estimate the responses to the main shock and a large after-shock. Results from this modeling effort are used to corroborate reports of structural response from staff present at the time of the main shock and aftershocks. Subsequent instrumentation of the structure is described and will be used to collect aftershock responses for validation of numerical models.

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“…Inspired by the commercialised traditional base isolator utilising natural rubber, Li et al developed a large capacity adaptive base isolator [18,19] that is the first adaptive base isolator utilising stiffness hardening MRE. This MRE adaptive base isolator consists of a classical laminated structure of steel and MRE layers from traditional rubber bearings [20,21]. The results obtained from testing the characteristics of this MRE adaptive base isolator showed it can increase lateral stiffness by up to 18 times [19].…”

Section: Introductionmentioning

confidence: 99%

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

Yang

Sun

Tian

et al. 2016

Mechanical Systems and Signal Processing

110

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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.

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High damping natural rubber seismic isolators

Cited by 25 publications

References 1 publication

A novel magnetorheological elastomer isolator with negative changing stiffness for vibration reduction

A novel magnetorheological elastomer isolator with negative changing stiffness for vibration reduction

Performance of the Base-Isolated Christchurch Women's Hospital in the September 4, 2010, Darfield Earthquake and the February 22, 2011, Christchurch Earthquake

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

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