Faculty Publications
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Item Influence of additives on the synthesis of carbonyl iron suspension on rheological and sedimentation properties of magnetorheological (MR) fluids(Institute of Physics Publishing helen.craven@iop.org, 2019) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumar, H.Magnetorheological (MR) fluid is one of the major constituent element in structural suspensions and damping characteristic in automobile applications. The major drawback is sedimentation in MR fluids, in the present study an attempt has been done to address the sedimentation issue. The synthesis and characterization of MR fluid in combination with clay and additives leads to improvement in sedimentation rate. The four different types of MR fluid were prepared in combination with clay, friction reducing agent and poly-alpha-olefin (PAO) oil naming as MRFp-1, 2, 3 and 4 as tabulated in table 1. The cost effective MRFp-3 shows better result compared to commercially available MR fluid with respect to off/on state shear stress, viscosity. It is also observed that in-house prepared MRFp-3 has better sedimentation than commercially available (LORD-132DG) up to 700 h. © 2019 IOP Publishing Ltd.Item Design and experimental characterization of a twin-tube MR damper for a passenger van(Springer Verlag service@springer.de, 2019) Desai, R.M.; Jamadar, M.E.H.; Kumar, H.; Joladarashi, S.; Raja Sekaran, S.C.The smart behavior of magneto-rheological (MR) fluid is used in the present work in designing, experimentally characterizing and analyzing a MR damper for automotive application using the twin-tube damper concept. A commercially available passive damper of a passenger van was tested to find the characteristic damping requirement of the vehicle. With this as reference, a twin-tube MR damper working in valve mode was designed and fabricated. The magnetic flux density induced in the fluid flow gap is maximized using Taguchi analysis and finite element method magnetics (FEMM) software. The FEMM results are validated by verifying with results obtained analytically using electromagnetic circuit theory. The MR damper filled with commercially available MR fluid was experimentally tested in damper testing machine. The results demonstrate that the force developed by the MR damper is indeed increasing with the value of the current supplied. At various frequencies of input oscillation, the energy dissipated by the MR damper in a single cycle increases significantly with current supplied. The novelty of this work is that a twin-tube MR damper working in valve mode was designed as a replacement for the passive damper used in a passenger van. The MR damper thus developed is capable of producing practical levels of damping force at actual operating frequencies and amplitudes of the passive damper in the passenger van. For further analysis, the behavior of the MR damper is modeled by using the Bouc–Wen model for hysteretic systems. A proportional–integral–derivative controller is used to track the desired damping force in time domain to demonstrate the application of the MR damper in a semi-active suspension system. © 2019, The Brazilian Society of Mechanical Sciences and Engineering.Item Evaluation of a commercial MR damper for application in semi-active suspension(Springer Nature, 2019) Desai, R.M.; Jamadar, M.E.H.; Kumar, H.; Joladarashi, S.; Rajasekaran, S.C.; Amarnath, G.As the rheology of a magneto-rheological (MR) fluid can be controlled by an externally applied magnetic field, the damping force generated by a MR damper can be controlled by varying the current supplied to an electromagnet inside the damper. This paper presents the experimental evaluation of such a MR damper RD-8040-1 by Lord Corporation, USA, and its application in a semi-active suspension. The experiments were carried out in damping force testing machine. Sinusoidal displacement input was given to the test damper. The set of experiments were repeated for different levels of current (0–1.5 A in steps of 0.25 A) supplied to the MR damper. Plots of force versus displacement for each frequency of excitation and plots of maximum force versus frequency of excitation show that higher values of current lead to elevated values of MR damper forces. This increase in MR damper load with current supplied is studied and analyzed to develop a mathematical model of the MR damper under investigation. The nonlinear softening hysteretic behavior of the MR damper is simulated by using genetic algorithm provided in the optimization toolbox of MATLAB. Calculations on energy dissipation and equivalent damping coefficient of the MR damper show that the same damper can make the suspension system behave as an underdamped system, critically damped system or overdamped system depending on the value of current supplied to it. The application of this MR damper for heavy vehicle driver’s seat suspension is explored with the help of MATLAB simulations. © 2019, Springer Nature Switzerland AG.Item Investigation of sedimentation, rheological, and damping force characteristics of carbonyl iron magnetorheological fluid with/without additives(Springer, 2020) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumar, H.In the present study, the magnetorheological fluid (MRF) samples are prepared using pure carbonyl iron particles (CIPs), CIPs/Claytone APA/Molyvan 855 additive, and friction reducer dispersed in poly-alpha-olefin oil. The scanning electron microscopy reveals that the Claytone additive morphology looks like a surface abundant in small folds, which connect the gaps between the spherical pure CIPs and prevent sedimentation in the MRF. The magnetic saturation properties are investigated through the vibrating sample magnetometer. The pure CIPs MRF shows (Ms) value as 146.12 emu/g, and the CIPs/Claytone APA/Molyvan indicates (Ms) as 55.12 emu/g. The magnetorheological flow curves, such as shear stress and viscosity as a function of shear rate, are investigated for the MRF samples through the magnetorheometer. The sedimentation analysis of the MRF is observed by visual inspection and shows that the CIPs/Claytone APA/Molyvan improved the sedimentation rate than the pure CIPs MRF. Finally, the experimental characterization of the prototype monotube MR damper is carried out using the hydraulic dynamic testing machine at 1.5 Hz frequency for damper peak–peak displacement length of ± 5 mm at three intervals of 0 h, 24 h, and 72 h in damper to know the effect on damping force for the prepared MRF samples against the sedimentation rate. © 2020, The Brazilian Society of Mechanical Sciences and Engineering.Item Synthesis of magnetorheological fluid and its application in a twin-tube valve mode automotive damper(SAGE Publications Ltd info@sagepub.co.uk, 2020) Madhavrao Desai, R.; Acharya, S.; Jamadar, M.-E.-H.; Kumar, H.; Joladarashi, S.; Sekaran, S.C.R.The change in rheological properties of smart materials like magnetorheological fluid when brought under the influence of a magnetic field can be utilized to develop magnetorheological devices where the output has to be continuously and quickly varied using electronic control interface. In the present study, magnetorheological fluid is synthesized and used as a smart fluid in a twin-tube magnetorheological damper operating in valve mode. The behavior of the magnetorheological fluid is experimentally characterized in a rheometer and mathematically modeled using Herschel–Bulkley model. The parameters of the Herschel–Bulkley model are expressed as polynomial functions of strength of the magnetic field in order to find the shear stress developed by the magnetorheological fluid at any given strength of the magnetic field applied. The magnetorheological damper, which was designed for application in a passenger van, is tested in the damper testing machine. The performance of the damper at different damper velocities and current supplied is studied. The range of values for the parameters of the experimental testing are chosen to emulate the actual conditions of operation in its intended application. Nondimensional analysis is performed, which links magnetorheological fluid rheological properties and geometrical parameters of magnetorheological damper design with the force developed by the damper. Finite element method magnetics is used to find the strength of the magnetic field at the fluid flow gap. Analytical methods are used to calculate the damper force developed due to the field-dependent yield stress and compared with experimental force values. The resulting dynamic range of the magnetorheological damper is also assessed. © The Author(s) 2020.Item Influence of different fumed silica as thixotropic additive on carbonyl particles magnetorheological fluids for sedimentation effects(Elsevier B.V., 2021) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumar, H.; Bhat Panemangalore, D.B.The present work reports the influence of different types of surface area, hydrophobic, and hydrophilic fumed silica mixed in silicone oil as a thixotropic additive on carbonyl particles based magnetorheological fluids (MRFs) were prepared. Scanning electron microscopy analysis confirms the fumed silica particles attached to the surfaces of CIPs. The vibrating sample magnetometer result shows the MRF4 and 5 have a better magnetic saturation value of 30.12 emu/gm and 40.12 emu/gm, respectively. The experimental rheological flow curve behaviours are investigated using the magnetorheometer. The Herschel–Bulkley rheological model is found to be in good agreement with the experimental curves and suggested shear thinning property is observed. The results showed that the hydrophilic silica with larger surface area type presented (i.e.MRF 4 and 5) better magnetorheological fluid characteristics in terms of shear stress, with a high value of dynamic yield stress, and have much-improved sedimentation ratio up to seven days. © 2021 Elsevier B.V.Item Rheological Properties of the In-house Prepared Magneto-rheological Fluid in the Pre-yield Region(Materials and Energy Research Center, 2022) Nagiredla, S.; Joladarashi, S.; Kumar, H.The essence of the present work is to study the rheological properties of the in-house prepared magnetorheological (MR) fluids in the pre-yield region since the rheological properties play a vital role in better understanding of vibration damping capabilities of MR fluids. In the present work, two different compositions of MR fluid samples were prepared with 24 and 30 volume percentages of carbonyl iron (CI) particles. Prepared MR fluid samples contain CI particles as a dispersive medium, silicone oil as a carrier fluid and white lithium grease as an anti-settling agent. The oscillating driving frequency and amplitude strain sweep tests are performed to investigate the rheological properties within the pre-yield region. The influences of driving frequency, strain amplitude, magnetic field and CI particles volume percentage on the rheological properties of the prepared MR fluids were assessed. The linear viscoelastic region of the prepared MR fluid sample was identified and the yield strain obtained was around 0.371%. It is observed that the volume percentage of CI particles in the MR fluid strongly influenced the rheological properties. © 2022 Materials and Energy Research Center. All rights reserved.Item A study on magnetorheological and sedimentation properties of soft magnetic Fe58Ni42 particles(Elsevier B.V., 2022) Aruna, M.N.; Rahman, M.R.; Joladarashi, S.; Kumara, H.; Meena, S.S.; Sarkar, D.; Umesh, C.K.In this study, the samples with two volume fractions (ϕ) of Fe58Ni42 (permalloy) i.e. (ϕ1 = 25 and ϕ2 = 30 %) were used as magnetic particles, silicone oil as a carrier fluid, and aluminium disterate as an additive. As received Fe58Ni42 particles surface morphology and composition of the Fe58Ni42 were investigated using field emission scanning electron microscopy (FESEM) coupled with energy dispersive spectroscopy (EDS), respectively. The X-ray Diffraction (XRD) structural information analysis confirmed Fe58Ni42 particles have a face-centered cubic phase, corresponding with the result of the high resolution transmission electron microscopy (HRTEM) characterization technique. The magnetorheological properties were tested via rotational rheometer at four different magnetic field strengths. The results show that sample PMRF-30 has a maximum shear stress, shear viscosity, and dynamic modulus greater than the PMRF-25 sample. In addition, experimental shear stress flow curves are well fitted with Herschel-Bulkley rather than Bingham and Casson rheological models. The permalloy based magnetorheological fluid (PMRF) samples were prepared with a 25 % volume fraction and a 30 % volume fraction of permalloy particles with a sample abbreviation of PMRF-25 and PMRF-30, respectively. Furthermore, the sedimentation stability of suspensions of both the samples was observed using visual inspection. This method result shows the sedimentation ratio with respect to time of 72 h was 31 % and 29 %, respectively. © 2022 Elsevier B.V.Item Characterization of an in-house prepared magnetorheological fluid and vibrational behavior of composite sandwich beam with magnetorheological fluid core(Sharif University of Technology, 2023) Nagiredla, S.; Joladarashi, S.; Kumar, H.In this research work, two different compositions of MR fluid samples with 24 and 30 percentage (%) volume fraction of carbonyl iron (CI) particles are prepared. Prepared MR fluid (MRF) samples contain carbonyl iron particles as a dispersive medium, silicone oil as a carrier fluid, and white lithium grease as an anti-settling agent. Influence of oscillating driving frequency, strain amplitude, magnetic field, and the percentage of CI particle on the rheological properties of the MR fluid samples are presented. Storage modulus and loss factor equations are estimated from the rheometry results using a linear regression method. The properties of MR fluid samples are taken to design and model the sandwich beams using ANSYS ACP software, where carbon epoxy composite material is used as the face layer and MR fluid as the core material. Modal, harmonic, and transient analysis studies have been conducted on all the modelled sandwich beams. Influence of MR fluid core material thickness, face layer thickness, CI particle volume percentage in the prepared MR fluid sample, and magnetic field on the vibrational response of the sandwich beams have been presented. Carbon-epoxy composites with an in-house made MRF sandwich beam has shown some significant results in the vibrational response. © 2023 Sharif University of Technology. All rights reserved.Item Influence of magneto-rheological fluid pocket configuration on the dynamic response of the composite sandwich beam(Taylor and Francis Ltd., 2024) Nagiredla, S.; Joladarashi, S.; Kumar, H.The present study investigated the influence of magnetorheological (MR) fluid pocket configuration and magnetic field intensity on the dynamic response of the composite sandwich beam under various boundary conditions. The classical beam theory is used to develop the finite element (FE) formulations for the composite sandwich beam element and it is validated with the available literature. Four MR fluid pocket configuration types are considered. The configuration types include 1/4th, 1/2th, 3/4th and the full length of the MR fluid pockets at different locations. Further, a detailed study of the influence of each MR fluid pocket configuration type on the natural frequency, loss factor, and frequency response are presented. The maximum 32.27% of deviation in the first fundamental frequency is observed for the simply-supported boundary condition. From the results obtained, it is concluded that the length and location of the MR fluid pocket have a considerable impact on the dynamic response and also observed that the effect of the configuration depends on the type of boundary condition used. © 2022 Taylor & Francis Group, LLC.