Browsing by Author "Shenoy, K.P."

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A novel approach to characterize the magnetic field and frequency dependent dynamic properties of magnetorheological elastomer for torsional loading conditions
(Elsevier B.V., 2020) Shenoy, K.P.; Poojary, U.; Gangadharan, K.V.
Magnetorheological elastomers (MRE) are potential resilient elements to improve the operating frequency range of a vibration isolator. The field-dependent characterization of MRE properties for varying input frequencies under lateral shear conditions has been well researched in past studies. In the present study, a novel approach to assess the magnetic field dependent rheological properties of magnetorheological elastomers under dynamic torsional loading is presented. Field and frequency-dependent properties are estimated from the dynamic blocked transfer stiffness method specified by ISO 10846. Viscoelastic properties represented in-terms of complex torsional stiffness and loss factor are estimated from the Lissajous curves within the linear viscoelastic (LVE) limit. Experiments are performed at a frequency range of 10 Hz–30 Hz under a constant input angular displacement. Magnetic field sensitive characteristics of MRE are evaluated under the field produced by a custom-made electromagnet. The results reveal a strong influence of field dependent variations on the complex stiffness in comparison with the input frequency. Variations observed in the loss factor suggests a dominance of the imaginary part of the complex stiffness on the energy dissipation. The reduced field induced enhancements in the complex stiffness are interpreted from the Magneto-static and structural based numerical simulations using ANSYS 19.1. © 2019 Elsevier B.V.
A novel approach to characterize the magnetic field and frequency dependent dynamic properties of magnetorheological elastomer for torsional loading conditions
(2020) Shenoy, K.P.; Poojary, U.; Gangadharan, K.V.
Magnetorheological elastomers (MRE) are potential resilient elements to improve the operating frequency range of a vibration isolator. The field-dependent characterization of MRE properties for varying input frequencies under lateral shear conditions has been well researched in past studies. In the present study, a novel approach to assess the magnetic field dependent rheological properties of magnetorheological elastomers under dynamic torsional loading is presented. Field and frequency-dependent properties are estimated from the dynamic blocked transfer stiffness method specified by ISO 10846. Viscoelastic properties represented in-terms of complex torsional stiffness and loss factor are estimated from the Lissajous curves within the linear viscoelastic (LVE) limit. Experiments are performed at a frequency range of 10 Hz 30 Hz under a constant input angular displacement. Magnetic field sensitive characteristics of MRE are evaluated under the field produced by a custom-made electromagnet. The results reveal a strong influence of field dependent variations on the complex stiffness in comparison with the input frequency. Variations observed in the loss factor suggests a dominance of the imaginary part of the complex stiffness on the energy dissipation. The reduced field induced enhancements in the complex stiffness are interpreted from the Magneto-static and structural based numerical simulations using ANSYS 19.1. 2019 Elsevier B.V.
Semi-Active Vibration Isolation of a Modular Magnetorheological Elastomer Device with ON-OFF and Fuzzy Logic Control
(Institute of Physics, 2025) Sathiyasai, S.; Kamath, N.; Shenoy, K.P.; Vinod, N.; Rao, G.; Gangadharan, G.
A modular device incorporating a magnetorheological elastomer (MRE) has been developed for vibration isolation applications. Following characterisation of its open-loop dynamic behaviour, this study investigates semi-active control strategies - ON/OFF control, proportional-integral-derivative (PID) control, and fuzzy logic control - targeting vibration attenuation at a dominant frequency of 12 Hz. These controllers dynamically adjust the MRE's damping properties by modulating the electromagnet's magnetic field in response to input vibration signals. Performance was evaluated using a shaker setup with a defined vibration spectrum, with the electromagnet's power consumption serving as a key metric. Experimental results show that ON/OFF control consumed the highest energy, drawing an average current of 2.5 A (26 W) and using 130 J over 5 s. While fuzzy logic control achieved the lowest consumption, a 72.5 % reduction compared to ON/OFF and 37.2 % less than PID. These findings highlight fuzzy logic control as the most energy-efficient strategy, offering significant power savings without compromising vibration isolation performance. Â© Published under licence by IOP Publishing Ltd.
Tunable Vibration Control in Power Tool Handles Using a Magnetorheological Elastomer Device
(Institute of Physics, 2025) Sathiyasai, S.; Kamath, N.; Shenoy, K.P.; Rai, S.K.; Tanappagol, P.S.; Rajesh; Gangadharan, G.
A novel modular device integrating a magnetorheological elastomer (MRE) has been designed for adaptable attachment to various power tool auxiliary handles using their standard circular clamp and T-headed bolt mechanism. The core of the electromagnet of the device serves as the primary attachment interface. A relative validation approach was adopted to characterize its vibration control capabilities across different tool configurations. Instead of device-specific testing, the modular unit, loaded with supplementary masses of 1 kg and 1.5 kg to simulate various power tool weights, was mounted on a shaker and exposed to a defined vibration spectrum. The effect of varying the magnetic field strength on the dynamic behavior of the MRE-based isolator was examined. Experimental results reveal a notable positive shift in the system's natural frequency of approximately 3 Hz, transitioning from 12 Hz to 15 Hz when the maximum magnetic field was applied. Concurrently, the transmitted vibration amplitude was substantially reduced, averaging around 12%, under the same maximum field conditions. These findings highlight the potential of this modular MRE device as a versatile and easily integrable solution for tunable vibration damping in a wide array of power tools. Its semi-active nature offers a pathway to significantly enhance user comfort, reduce operator fatigue, and improve overall operational stability across diverse applications. Â© Published under licence by IOP Publishing Ltd.