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Norman M. Wereley - One of the best experts on this subject based on the ideXlab platform.

  • Gripping characteristics of an electromagnetically activated Magnetorheological Fluid-based gripper
    AIP Publishing LLC, 2018
    Co-Authors: Young T. Choi, Christine M. Hartzell, Thomas Leps, Norman M. Wereley
    Abstract:

    The design and test of a Magnetorheological Fluid (MRF)-based universal gripper (MR gripper) are presented in this study. The MR gripper was developed to have a simple design, but with the ability to produce reliable gripping and handling of a wide range of simple objects. The MR gripper design consists of a bladder mounted atop an electromagnet, where the bladder is filled with an MRF, which was formulated to have long-term stable sedimentation stability, that was synthesized using a high viscosity linear polysiloxane (HVLP) carrier Fluid with a carbonyl iron particle (CIP) volume fraction of 35%. Two bladders were fabricated: a magnetizable bladder using a Magnetorheological elastomer (MRE), and a passive (non-magnetizable) silicone rubber bladder. The holding force and applied (initial compression) force of the MR gripper for a bladder fill volume of 75% were experimentally measured, for both magnetizable and passive bladders, using a servohydraulic material testing machine for a range of objects. The gripping performance of the MR gripper using an MRE bladder was compared to that of the MR gripper using a passive bladder

  • characterization of stratification for an opaque highly stable Magnetorheological Fluid using vertical axis inductance monitoring system
    Journal of Applied Physics, 2015
    Co-Authors: Youngtai Choi, Lei Xie, Changrong Liao, Norman M. Wereley
    Abstract:

    A key requirement for the commercialization of various Magnetorheological Fluid (MRF)-based applications is sedimentation stability. In this study, a high viscosity linear polysiloxane (HVLP), which has been used for shock absorbers in heavy equipment, is proposed as a new carrier Fluid in highly stable MRFs. The HVLP is known to be a thixotropic (i.e., shear thinning) Fluid that shows very high viscosity at very low shear rate and low viscosity at higher shear rate. In this study, using the shear rheometer, the significant thixotropic behavior of the HVLP was experimentally confirmed. In addition, a HVLP carrier Fluid-based MRF (HVLP MRF) with 26 vol. % was synthesized and its sedimentation characteristics were experimentally investigated. But, because of the opacity of the HVLP MRF, no mudline can be visually observed. Hence, a vertical axis inductance monitoring system (VAIMS) applied to a circular column of Fluid was used to evaluate sedimentation behavior by correlating measured inductance with the v...

  • Magnetorheological Fluid composites synthesized for helicopter landing gear applications
    Journal of Intelligent Material Systems and Structures, 2013
    Co-Authors: Louise A. Powell, Norman M. Wereley
    Abstract:

    Magnetorheological Fluid composites were formulated in this study to investigate their performance for potential use in landing gear hydraulic systems, such as shock struts. The Magnetorheological Fluids synthesized here utilized three hydraulic oils certified for use in landing gear, two average diameters of spherical magnetic particles, and a lecithin surfactant. The magnetorheology of these Fluids was characterized, including (a) magnetorheology (yield stress and viscosity) as a function of magnetic field, (b) sedimentation analysis using an inductance-based sensor, (c) cycling of a small-scale Magnetorheological damper undergoing sinusoidal excitations at frequencies of 2.5 and 5 Hz, and (d) impact testing of an Magnetorheological damper for a range of magnetic field strengths and velocities using a free-flight drop tower facility. The goal of this research is to analyze the performance of these Magnetorheological Fluid composites, compare their behavior to standard commercial Magnetorheological Fluid...

  • Adaptive Snubber-Type Magnetorheological Fluid-Elastomeric Helicopter Lag Damper
    AIAA Journal, 2010
    Co-Authors: Grum T. Ngatu, Norman M. Wereley, Curt S. Kothera
    Abstract:

    A snubber-type Magnetorheological Fluid-elastomeric lag damper is developed to provide adaptive lead-lag damping augmentation for a hingeless helicopter rotor. The Magnetorheological Fluid-elastomeric lag damper consists of a flow valve, a flexible snubber body, and a flexible center wall separating the body into two Fluid chambers. Magnetorheological Fluid enclosed in the snubber body can flow through two Magnetorheological valves and be activated by a magnetic field in the valves. Consistent with the loading conditions for a helicopter lag damper, the Magnetorheological Fluid-elastomeric damper is tested under single and dual frequency excitations. The complex modulus method was used to compare the Magnetorheological Fluid-elastomeric device damping performance with the baseline passive Fluidlastic damper. A significant controllable damping range is observed as current is applied to the Magnetorheological valve in the Magnetorheological Fluid-elastomeric damper. Furthermore, to account for the nonlinear hysteresis behavior ofthe Magnetorheological Fluid-elastomeric damper and estimate the damping force, a time-domain hydromechanical model is formulated based on lumped parameters. Model parameters are established using damper geometry, material properties, and experimental data. The model is then applied to simulate the force vs displacement response and force time history under both single and dual frequency excitations.

  • hybrid Magnetorheological Fluid elastomeric lag dampers for helicopter stability augmentation
    Smart Materials and Structures, 2008
    Co-Authors: Norman M. Wereley
    Abstract:

    A laboratory demonstration of a hybrid Magnetorheological Fluid?elastomeric (MRFE) damper is investigated for adjustable or programmable lag mode damping in helicopters, so that damping requirements can be varied as a function of different flight conditions. The laboratory demonstration of this hybrid MRFE lag damper consists of a double lap shear elastomeric damper in parallel with two Magnetorheological (MR) flow mode dampers. This is compared to a damper where only elastomeric materials are implemented, i.e., a double lap shear specimen. The relationship between the output force and the quasi-steady harmonic displacement input to a flow mode MR damper is exploited, where the output force can be adjusted as a function of applied magnetic field. Equivalent viscous damping is used to compare the damping characteristics of the hybrid damper to a conventional elastomeric damper under steady-state sinusoidal displacement excitation. To demonstrate feasibility, a hybrid MRFE damper test setup is designed, and single frequency (lag frequency or rotor in-plane bending frequency) and dual frequency (lag frequency and rotor frequency) tests are conducted under different magnetic fields. The hybrid MRFE damper exhibits amplitude-dependent damping behavior. However, with application of a magnetic field, the damping level is controlled to a specific damping level objective as a function of displacement amplitude. Similarly, under dual frequency conditions, damping degradation at the lag frequency, because of lag motion at the rotor frequency, can also be recovered by increasing magnetic field. A time-domain analysis is developed to study the nonlinear dynamic behavior of the hybrid MRFE damper. Using rate-dependent elasto-slides, the amplitude-dependent behavior of the hybrid MRFE damper is accurately reconstructed using both constant and current-dependent (i.e.?controllable) parameters. The analysis is physically motivated and can be applied to the elastomer and MR Fluid damper components separately.

Dao-ming Wang - One of the best experts on this subject based on the ideXlab platform.

  • Influence of wall characteristics on transmittable torque of Magnetorheological Fluid
    Journal of Intelligent Material Systems and Structures, 2013
    Co-Authors: Tian Zuzhi, Fei Chen, Dao-ming Wang
    Abstract:

    Magnetorheological Fluid is a controllable Fluid that exhibits changeable yield stress and attractive rheological properties on the applied magnetic field. In order to enhance the yield stress of Magnetorheological Fluid and suppress wall slip effect in the case of transmission, the mechanism and corresponding influence factors of the wall slip effect were investigated theoretically and experimentally. Different transmittable disks and a Magnetorheological transmission test-bed were built, and the influence of wall characteristics on the transmission capacity of Magnetorheological Fluids was investigated on the test-bed. The results showed that the material types, surface roughness, and surface textures of transmission wall have distinct influence on the transmission capacity of Magnetorheological Fluid. The transmission wall with a groove depth of 0.2 mm, higher material magnetic permeability, higher surface roughness, radial grooves at the surface, and higher groove density was determined as the best tr...

  • Design and experimental evaluation of a multidisk Magnetorheological Fluid actuator
    Journal of Intelligent Material Systems and Structures, 2012
    Co-Authors: Dao-ming Wang, Youfu Hou
    Abstract:

    A new multidisk Magnetorheological Fluid actuator was proposed using the shear stress of Magnetorheological Fluid between rotating disks. The transmission torque was calculated based on the Bingham model, and the magnetic circuit was designed in accordance with electromagnetic theory. Then, a magnetostatic simulation was conducted to validate the designed magnetic circuit. Furthermore, an experimental study was performed to investigate the performance of the prototype. The results show that the transmission torque increases approximately linearly with the input current within the saturation range of Magnetorheological Fluid. Both the input current and the gap thickness have little influence on the dynamic response property of the proposed Magnetorheological Fluid actuator. Moreover, the temperature of Magnetorheological Fluid increases linearly with the time in the slip and loaded states, and the greater the slip power is, the faster the temperature rises. Furthermore, the temperature rise of magnetorheol...

Shuaishuai Sun - One of the best experts on this subject based on the ideXlab platform.

  • a variable resonance Magnetorheological Fluid based pendulum tuned mass damper for seismic vibration suppression
    Mechanical Systems and Signal Processing, 2019
    Co-Authors: Matthew Christie, Shuaishuai Sun, Lei Deng, Donghong Ning, Shiwei Zhang
    Abstract:

    Abstract Seismic events leading to catastrophic outcomes around the world, particularly in built-up regions surrounding fault lines, often have high death tolls and cause costly damages to societies’ existing infrastructure. To suppress damaging vibrations in multi-story buildings across a wide frequency spectrum, much research has been put into the study of variable-resonance tuned mass dampers, which maintain their usefulness across a range of frequencies, unlike passive alternatives. As a novel implementation of fast responsive Magnetorheological materials to enable variable resonance, this paper presents a prototype Magnetorheological-Fluid-based pendulum tuned mass damper, integrating a differential gearbox to yield a damper-controlled transmission between the pendulum mass and a mechanical spring. The device is demonstrated to be highly effective, at its best reducing peak relative displacement by 12.8%, and peak acceleration by 22.0%, in contrast to comparable passive tuning modes in scale-building seismic experiments. This is owed to its controllable resonance which can be increased by 104% from its base value at 2.24 Hz. Further, other performance benefits are demonstrated in RMS structure displacement, and interstory drift ratio.

  • development of a novel variable stiffness and damping Magnetorheological Fluid damper
    Smart Materials and Structures, 2015
    Co-Authors: Shuaishuai Sun, Jian Yang, Huaxia Deng, Gursel Alici
    Abstract:

    This paper reports a novel Magnetorheological Fluid (MRF)-based damper, which synergizes the attributes of variable stiffness and damping through the compact assembly of two MRF damping units and a spring. The magnetic field densities of the two damping units were analyzed. After the prototype of the new MRF damper, a hydraulically actuated MTS machine was used to test the damper's performance, including stiffness variability and damping variability, amplitude-dependent responses and frequency-dependent responses. A new mathematical model was developed to describe the variable stiffness and damping MRF damper. The successful development, experimental testing and modeling of this innovative variable stiffness and damping MRF damper make the true design and implementation of the concept of variable stiffness and damping feasible.

Gursel Alici - One of the best experts on this subject based on the ideXlab platform.

  • development of a novel variable stiffness and damping Magnetorheological Fluid damper
    Smart Materials and Structures, 2015
    Co-Authors: Shuaishuai Sun, Jian Yang, Huaxia Deng, Gursel Alici
    Abstract:

    This paper reports a novel Magnetorheological Fluid (MRF)-based damper, which synergizes the attributes of variable stiffness and damping through the compact assembly of two MRF damping units and a spring. The magnetic field densities of the two damping units were analyzed. After the prototype of the new MRF damper, a hydraulically actuated MTS machine was used to test the damper's performance, including stiffness variability and damping variability, amplitude-dependent responses and frequency-dependent responses. A new mathematical model was developed to describe the variable stiffness and damping MRF damper. The successful development, experimental testing and modeling of this innovative variable stiffness and damping MRF damper make the true design and implementation of the concept of variable stiffness and damping feasible.

Xiaojie Wang - One of the best experts on this subject based on the ideXlab platform.