Faculty Publications

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Author: search.filters.author.Gurubasavaraju, T.M.

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    A study of influence of material properties on magnetic flux density induced in magneto rheological damper through finite element analysis
    (EDP Sciences edps@edpsciences.com, 2018) Gurubasavaraju, T.M.; Kumar, K.; Arun, M.
    Magnetorheological fluids are smart materials, which are responsive to the external stimulus and changes their rheological properties. The damper performance (damping force) is dependent on the magnetic flux density induced at the annular gap. Magnetic flux density developed at fluid flow gap of MR damper due to external applied current is also dependent on materials properties of components of MR damper (such as piston head, outer cylinder and piston rod). The present paper discus about the influence of different materials selected for components of the MR damper on magnetic effect using magnetostatic analysis. Different materials such as magnetic and low carbon steels are considered for piston head of the MR damper and magnetic flux density induced at fluid flow gap (filled with MR fluid) is computed for different DC current applied to the electromagnetic coil. Developed magnetic flux is used for calculating the damper force using analytical method for each case. The low carbon steel has higher magnetic permeability hence maximum magnetic flux could pass through the piston head, which leads to higher value of magnetic effect induction at the annular gap. From the analysis results it is observed that the magnetic steel and low carbon steel piston head provided maximum magnetic flux density. Eventually the higher damping force can be observed for same case. © The Authors, published by EDP Sciences, 2018.
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    Optimisation of monotube magnetorheological damper under shear mode
    (Springer Verlag service@springer.de, 2017) Gurubasavaraju, T.M.; Kumar, H.; Mahalingam, M.
    Magnetorheological dampers (MR) are one of the semi active devices, which has the capability of providing variable damping force for the variable input current. Induced force is directly dependent on the amount of magnetic flux density developed in effective fluid flow gap of the MR damper. In the present work, influence of material properties on the magnetic flux is investigated by considering magnetic and nonmagnetic material for the outer cylinder of shear mode type MR damper. Magnetostatic analysis is carried out to obtain magnetic flux density for the initial configuration of the MR damper. From the analysis, it is found that usage of magnetic material cylinder which is insulated with nonmagnetic material provided higher value of magnetic flux and damping force. The geometric optimisation of MR damper is carried out to obtain the maximum flux density in the fluid flow gap. The objective function of the optimisation includes the maximum magnetic flux density and minimising fluid flow gap. Design variables considered are fluid flow gap, number of turns in the electromagnetic coil, length of the flange and DC current input. The optimisation is performed through response surface method using finite element analysis software (ANSYS). The best optimal design parameters are obtained by choosing the appropriate value of objective function. The best configuration of the design parameters, which induce the maximum magnetic flux density, is identified. The force induced in the MR damper is estimated analytically and a comparative study of the optimised and non-optimised results was carried out. © 2017, The Brazilian Society of Mechanical Sciences and Engineering.
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    Evaluation of optimal parameters of MR fluids for damper application using particle swarm and response surface optimisation
    (Springer Verlag service@springer.de, 2017) Gurubasavaraju, T.M.; Kumar, H.; Mahalingam, A.
    The controllable rheological properties of MR fluid exhibit viscoelastic properties within pre-yield, which are essential for the characterization of MR dampers for the isolation of vibration. In the present work, using particle swarm optimisation (PSO), it is identified that the proportion of MR fluid constituents, fluid gap and current are the parameters which influence majorly on the rheological properties and damping effect of MR damper. Initially, rheological properties of the prepared MR fluid samples are determined using rotational plate–plate type rheometer with the magnetorheological device cell attachment by keeping three levels of gap between the parallel plates. Three different proportions of MR fluid are prepared based on the volume fraction of carbonyl iron particle, i.e., 25, 30 and 35% in the silicone carrier fluid along with 1% of lithium-based grease as stabiliser. The objective function of this optimisation problem is to maximise the shear stress and damping force of the MR damper. The design of experiment (DOE) is employed to obtain the various combinations of parameters and their respective responses. The interaction of the regression model obtained from the DOE is used in PSO to evaluate the optimal parameters. The results indicated that the MR fluid with the particle concentration of 31% is the optimal proportion for MR damper application. © 2017, The Brazilian Society of Mechanical Sciences and Engineering.
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    An approach for characterizing twin-tube shear-mode magnetorheological damper through coupled FE and CFD analysis
    (Springer Verlag service@springer.de, 2018) Gurubasavaraju, T.M.; Kumar, H.; Mahalingam, A.
    The most promising technology in the field of semi-active suspension systems is the use of magnetorheological property of MR fluid, whose material behavior can be controlled through external magnetic field. Devices developed based on this principle are adaptive and controllable as desired for a specific application. It is important to understand the damping characteristics of these devices before employing them, using experimental or computational approaches. In the present work, both experimental and computational methods have been adopted for characterizing a twin-tube MR damper with an intention to develop a computational approach as an alternative to experimental test in the preliminary design stage. Initially, experimental characterization of MR damper was carried out at 1.5 and 2 Hz frequencies for damper stroke length of ± 5 mm under different DC currents ranging from 0.1 to 0.4 A. Later, coupled finite-element and computational fluid dynamic analysis has been carried out to estimate the damping force under same conditions as used in the experiment. The results of computation are in good agreement with experimental ones. Furthermore, using this computational approach, the damping force at different frequencies of 1.5, 2, 3, and 4 Hz has been estimated and its time histories are also plotted. The influence of fluid flow gap on the damping force has been determined and results revealed that damping force behaves inversely with fluid flow gap. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.
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    Vibration analysis of fully and partially filled sandwiched cantilever beam with magnetorheological fluID
    (Taylor's University, 2020) Srinivasa, N.; Gurubasavaraju, T.M.; Kumar, H.; Arun, M.
    This paper presents the experimental and computational study on damping effect of the fully and partially filled sandwich cantilever beams. The sandwich beams referred as adaptive beams have a core layer filled with magnetorheological fluid (MRF) between two aluminium face plates. Forced vibration tests were conducted under different magnetic fields with the application of external force in the form of sinusoidal sweep excitation using an electrodynamic shaker. Effect on damping and natural frequency due to change in MR fluid core thickness of 2 mm, 4 mm and 6 mm for the fully filled beam and fluid core length of 75 mm, 150 mm and 250 mm for partially filled beam were investigated. Modal and harmonic analysis of the MR sandwich beams were carried out using FE analysis. The results indicated that in the case of the fully filled beam, a reduction in the natural frequency with the increase in MR fluid core thickness and a better damping at 2 mm fluid core thickness were observed. Also, in the case of the partially filled beam a reduction in natural frequency and improvement in damping is found with the increase in core length and magnetic field. The results of these analyses can be useful in designing the sandwich beams for structural application. © School of Engineering, Taylor's University