Performance of a large-scale magnetorheological elastomer–based vibration isolator for highway bridges

2018 ◽  
Vol 29 (20) ◽  
pp. 3890-3901 ◽  
Author(s):  
Siddaiah Yarra ◽  
Faramarz Gordaninejad ◽  
Majid Behrooz ◽  
Gokhan Pekcan ◽  
Ahmad M Itani ◽  
...  
Keyword(s):  
Large Scale ◽  
Compressive Force ◽  
Shear Stiffness ◽  
Highway Bridges ◽  
Loading Frequency ◽  
Vibration Isolator ◽  
Magnetorheological Elastomer ◽  
Lap Shear ◽  
Magnetorheological Effect ◽  
Bridge Bearings

This study presents an experimental investigation on the magnetorheological effect of a new magnetorheological elastomer–based adaptive bridge isolation bearing system. Two identical magnetorheological elastomer–based adaptive bridge bearings (isolators) were designed and fabricated. Electromagnets were incorporated to create a closed-loop magnetic path in the magnetorheological elastomer layers. A double-lap shear and compression test setup was utilized to characterize the mechanical properties of the system subjected to scaled structural cyclic forces and strains. Experimental results demonstrated that the effective stiffness of adaptive bridge bearings increases with increased applied magnetic field and a compressive force resulted in larger apparent shear stiffness. Also, increasing loading frequency resulted in larger apparent shear stiffness and lower magnetorheological effect and similarly, however, a compressive force resulted in smaller magnetorheological effects.

Fabrication and characterization of highly controllable magnetorheological material in compression mode

2020 ◽  
Vol 31 (14) ◽  
pp. 1641-1661 ◽  
Author(s):  
Amin Fereidooni ◽  
Afonso Martins ◽  
Viresh Wickramasinghe ◽  
Afzal Suleman
Keyword(s):  
Magnetic Fields ◽  
Loss Factor ◽  
Magnetorheological Fluid ◽  
Loading Frequency ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Equivalent Damping ◽  
Magnetorheological Effect ◽  
Equivalent Damping Coefficient

This article is focused on the development and characterization of highly controllable magnetorheological materials for stiffness and damping control in semi-active control applications. Two types of magnetorheological materials are developed in-house: magnetorheological elastomer with soft base elastomer, and magnetorheological fluid encapsulated in regular elastomer, namely magnetorheological fluid-elastomer. In both cases of magnetorheological elastomers and magnetorheological fluid-elastomers, the samples are evaluated using in-house-developed shear and compression test rigs, which are equipped with electromagnets and Hall effect sensors for measuring the magnetic field. These features provide the capability to precisely control a wide range of magnetic fields during the experiments. In the case of magnetorheological elastomers, the experimental results of the in-house magnetorheological elastomers are compared with commercially available counterparts made of hard base elastomer. It is shown that the controllability of the material, that is, the relative magnetorheological effect, is significantly improved in the case of magnetorheological elastomer with soft base elastomer. In addition to various magnetic fields, the samples are subjected to a range of loading amplitudes and frequencies. A general trend is observed where the frequency and strain amplitude cause an opposite effect on both the shear and compressive moduli: the increase in frequency gives rise to a higher value of modulus whereas the increase in amplitude reduces the modulus. Furthermore, the effect of bonding on the performance of the magnetorheological elastomers in compression mode is evaluated and the results indicate a significant increase in the modulus and decrease in the loss factor. In all the cases, however, the change of loss factor does not exhibit a predictable trend as a function of magnetic fields. In order to investigate a magnetorheological-based solution for controlling the damping of a semi-active system, magnetorheological fluid-elastomer samples are made in-house. These samples are fabricated using three different iron concentrations, and are tested in compression (squeeze) mode. The results of these experiments confirm that the equivalent damping coefficient of the material rises with the increase in magnetic field, and this effect becomes stronger as the iron concentration of magnetorheological fluids increases. It is also demonstrated that the magnetorheological effect is highly dependent on the loading frequency and amplitude, where the equivalent damping coefficient decreases with the increase in loading frequency and amplitude. In all the aforementioned cases, the stiffness of magnetorheological fluid-elastomers exhibits minor changes, which offers the in-house-developed magnetorheological fluid-elastomers as a damping only control option, a development that is different from the magnetorheological fluid-elastomers reported in the literature.

Performance of natural rubber and silicone-based magnetorheological elastomers under large-strain combined axial and shear loading

2018 ◽  
Vol 30 (2) ◽  
pp. 228-242 ◽  
Author(s):  
Siddaiah Yarra ◽  
Faramarz Gordaninejad ◽  
Majid Behrooz ◽  
Gokhan Pekcan
Keyword(s):  
Natural Rubber ◽  
Large Strain ◽  
Axial Stress ◽  
Shear Loading ◽  
Structural Vibration ◽  
Large Strains ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Lap Shear ◽  
Magnetorheological Effect

This study presents an experimental investigation on large-strain behavior of natural rubber– and silicone-based magnetorheological elastomers within a larger scope of structural vibration mitigation due to wind, traffic and seismic events. Magnetorheological elastomer samples with different weight percentages of iron particles, additives, and elastomer matrix were fabricated. The microstructures of specimens were examined, and their mechanical properties were investigated by a unique electromagnetic double-lap shear experimental setup capable of applying simultaneous compression and shear loads. The experimental results demonstrated that the isotropic natural rubber–based magnetorheological elastomers exhibit about 30% magnetorheological effect under large strains, while they achieve a higher magnetorheological effect under the combined axial and shear loading. The magnetorheological effect was 92% and 33% for 10% and 100% shear strains when 100 psi axial stress was applied. A natural rubber–based magnetorheological elastomer was further investigated applying dynamic cyclic load with and without compression load for different strains, frequencies, and magnetic field intensities. It was observed that for higher frequency, magnetorheological effect was reduced. Magnetorheological effects were 73% and 29% for 0.1 and 10 Hz frequencies, respectively, under 100 psi axial stress at 150% shear strain. The result of this study suggests that isotropic natural rubber–based magnetorheological elastomers may be suitable for high-demand-force applications, and in particular, in civil structures.

scholarly journals Experimental Study on the Behavior of X-Section Pile Subjected to Cyclic Axial Load in Sand

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Yiwei Lu ◽  
Hanlong Liu ◽  
Changjie Zheng ◽  
Xuanming Ding
Keyword(s):  
Axial Load ◽  
Large Scale ◽  
Cross Sectional Area ◽  
Load Test ◽  
Dynamic Responses ◽  
Scale Model ◽  
Loading Frequency ◽  
Sectional Area ◽  
Cross Sectional ◽  
Shaft Friction

X-section cast-in-place concrete pile is a new type of foundation reinforcement technique featured by the X-shaped cross-section. Compared with a traditional circular pile, an X-section pile with the same cross-sectional area has larger side resistance due to its larger cross-sectional perimeter. The behavior of static loaded X-section pile has been extensively reported, while little attention has been paid to the dynamic characteristics of X-section pile. This paper introduced a large-scale model test for an X-section pile and a circular pile with the same cross-sectional area subjected to cyclic axial load in sand. The experimental results demonstrated that cyclic axial load contributed to the degradation of shaft friction and pile head stiffness. The dynamic responses of X-section pile were determined by loading frequency and loading amplitude. Furthermore, comparative analysis between the X-section pile and the circular pile revealed that the X-section pile can improve the shaft friction and reduce the cumulative settlement under cyclic loading. Static load test was carried out prior to the vibration tests to investigate the ultimate bearing capacity of test piles. This study was expected to provide a reasonable reference for further studies on the dynamic responses of X-section piles in practical engineering.

Development and Modeling of a Highly-Adjustable Base Isolator Utilizing Magnetorheological Elastomer

2013 ◽  
Author(s):  
Yancheng Li ◽  
Jianchun Li
Keyword(s):  
Analytical Model ◽  
Seismic Isolation ◽  
Large Scale ◽  
Lateral Stiffness ◽  
Magnetorheological Elastomer ◽  
Isolation System ◽  
Vertical Loading ◽  
Base Isolator ◽  
Field Dependent ◽  
Dependent Property

This paper presents a recent research breakthrough on the development of a novel adaptive seismic isolation system as the quest for seismic protection for civil structures, utilizing the field-dependent property of the magnetorheological elastomer (MRE). A highly-adjustable MRE base isolator was developed as the key element to form smart seismic isolation system. The novel isolator contains unique laminated structure of steel and MRE layers, which enable its large-scale civil engineering applications, and a solenoid to provide sufficient and uniform magnetic field for energizing the field-dependent property of MR elastomers. With the controllable shear modulus/damping of the MR elastomer, the developed adaptive base isolator possesses a controllable lateral stiffness while maintaining adequate vertical loading capacity. Experimental results show that the prototypical MRE base isolator provides amazing increase of lateral stiffness up to 1630%. Such range of increase of the controllable stiffness of the base isolator makes it highly practical for developing new adaptive base isolation system utilizing either semi-active or smart passive controls. To facilitate the structural control development using the adaptive MRE base isolator, an analytical model was developed to stimulate its behaviors. Comparison between the analytical model and experimental data proves the effectiveness of such model in reproducing the behavior of MRE base isolator, including the observed strain stiffening effect.

scholarly journals Experimental and Numerical Study of Viscoelastic Properties of Polymeric Interlayers Used for Laminated Glass: Determination of Material Parameters

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2241 ◽  
Author(s):  
Tomáš Hána ◽  
Tomáš Janda ◽  
Jaroslav Schmidt ◽  
Alena Zemanová ◽  
Michal Šejnoha ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Shear Stiffness ◽  
Ethylene Vinyl Acetate ◽  
Material Model ◽  
Polyvinyl Butyral ◽  
Experimental Program ◽  
Model Parameters ◽  
Laminated Glass ◽  
Material Parameters ◽  
Lap Shear

An accurate material representation of polymeric interlayers in laminated glass panes has proved fundamental for a reliable prediction of their response in both static and dynamic loading regimes. This issue is addressed in the present contribution by examining the time–temperature sensitivity of the shear stiffness of two widely used interlayers made of polyvinyl butyral (TROSIFOL BG R20) and ethylene-vinyl acetate (EVALAM 80-120). To that end, an experimental program has been executed to compare the applicability of two experimental techniques, (i) dynamic torsional tests and (ii) dynamic single-lap shear tests, in providing data needed in a subsequent calibration of a suitable material model. Herein, attention is limited to the identification of material parameters of the generalized Maxwell chain model through the combination of linear regression and the Nelder–Mead method. The choice of the viscoelastic material model has also been supported experimentally. The resulting model parameters confirmed a strong material variability of both interlayers with temperature and time. While higher initial shear stiffness was observed for the polyvinyl butyral interlayer in general, the ethylene-vinyl acetate interlayer exhibited a less pronounced decay of stiffness over time and a stiffer response in long-term loading.

Study on the Mechanical Properties of Magnetorheological Elastomers

2013 ◽  
Vol 774-776 ◽  
pp. 54-57 ◽  
Author(s):  
Yu Fei Wang ◽  
Guo Fei Wang
Keyword(s):  
Mechanical Properties ◽  
Large Deformation ◽  
Shear Mode ◽  
Magnetorheological Elastomer ◽  
Test Set ◽  
Magnetorheological Elastomers ◽  
Magnetorheological Effect ◽  
Magnetic Filed ◽  
Mr Effect

A polyurethane-based magnetorheological elastomer (MR elastomer) was designed, and the magnetorheological effect (MR effect) under shear mode was systematically tested by the designed test set. The results show that the relative MR effect increases with the exterior magnetic filed strength and decreases as the incentive amplitudes increasing. The preload displacement also directly determines the relative MR effect and too large deformation will make the MR effect decreased sharply. But the incentive frequency has no very obviously influence on the relative MR effect.

Calculation of Horizontal Rigidity of the Plate Type Elastomeric Pad Bearing for Highway Bridge

2012 ◽  
Vol 204-208 ◽  
pp. 2244-2247
Author(s):  
Jie Wang ◽  
Jian Xin Liu
Keyword(s):  
Structural Parameters ◽  
Single Layer ◽  
Highway Bridges ◽  
Highway Bridge ◽  
Rubber Layer ◽  
Republic Of China ◽  
Communications Industry ◽  
Industry Standard ◽  
Bridge Bearings ◽  
Plate Type

The plate type elastomeric pad bearing is the most commonly used in highway bridge bearings. In the seismic design of bridges, the horizontal rigidity of the bearing is an important calculation parameters. The specific values of each parameter in the formula are not clear, and it can not provide a clear computation measures, although the formula of horizontal rigidity is given in the specification. Against Series bearings in plate type elastomeric pad bearing for Highway Bridge (JT/T4-2004), the People's Republic of China Communications Industry Standard, the structural parameters of the bearing are systematically introduced, including the shape factor, the bearing thickness, the thickness of the single-layer rubber and the total thickness of rubber layer. The methodology and detailed steps of the bearing horizontal rigidity are then analyzed and summarized by the formulas above. At last several examples of the different type of bearings are given. Some reference are Provided for the calculation of the stiffness frequently of plate type elastomeric pad bearing which are frequently used for highway bridges.

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