Faculty Publications
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Item Experimental investigation of frequency and damping characteristics of magneto-rheological fluid core sandwich beams(American Institute of Physics Inc. subs@aip.org, 2020) Nagiredla, S.; Joladarashi, S.; Kumar, H.In dynamic systems mechanical vibration amplitudes may range from a few nanometres to meters. When the vibration amplitudes are high the system may lead to failure or lost it function. Structures often tend to failure because of the high vibration amplitudes. These vibrations can be reduced by changing the stiffness or damping of the structure. One of the approaches is semi-active damping achieved by using Magneto-rheological fluid (MRF) as core material in a sandwiched beam. Magneto-rheological(MR) fluids change from fluid state to quasi-solid state when it is activated by a magnetic field. Adding MR fluids to mechanical systems may significantly improve their dynamic response. This study aims to analyse the free vibration response of the cantilever sandwich beam filled with the MR fluid as core material with Magnetic field intensity. A sandwich cantilever beam with Composite material as face layer and Magneto-rheological fluid as core was fabricated. Free Vibration test is performed on a sandwich beam filled with MR fluid under the external magnetic field generated by permanent magnets. Magnitude of Viscoelastic moduli of the MR fluid increases with magnetic field intensity as the fluid becomes semi-solid. The aim of the work is to analyse the influence of Magneto-rheological effect on the beam response with respect to externally applied magnetic field. Vibrations of the beam are registered with magnetic field and without magnetic field strength. Obtained data is utilized to analyse the dependency of magnetic field strength on the beams natural frequency and damping. © 2020 Author(s).Item Passive and Active Vibration Control of Hybrid Composite Sandwich Beam(Springer Science and Business Media Deutschland GmbH, 2024) Nagiredla, S.; Joladarashi, S.; Kumar, H.Vibration control is a rapidly developing field and research is being carried out on different methods to attenuate the harmful vibration levels. Composite materials carry the advantage of providing enhanced material properties compared to that of conventional materials. This work mainly focuses on conducting the transient analysis on hybrid composite sandwich beams with viscoelastic core and to implement the linear quadratic regulator (LQR) and Proportional, Integrate and derivative (PID) controllers. The transient response of the hybrid composite sandwich beam with the viscoelastic core is presented and the active vibration control study was implemented on the sandwich beam’s transfer function which is obtained by using system identification technique. It was found that there is a substantial change in settling time as well as vibrational amplitude. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Influence of Material and Geometrical Properties on Static and Dynamic Behavior of MR Fluid Sandwich Beam: Finite Element Approach(Institute for Ionics, 2023) Nagiredla, S.; Joladarashi, S.; Kumar, H.Magnetorheological (MR) fluid can transform its rheological properties when it is exposed to a magnetic field. This nature of the MR fluid provides an additional stiffness and damping for the sandwich beam applications. The Lagrange’s method is used to derive the equations of motion for the current finite element formulation. The influence of an applied magnetic field, thickness ratio and the length parameter on the static deflection, loss factor and natural frequency for different boundary conditions are presented. Further, the study is extended to plot the real and imaginary mode shapes corresponding to the fundamental frequencies. The geometrical and material properties considered in the present study showed a significant influence on static deflection and vibration amplitude of the sandwich beam. There is a maximum of 22.74% decrease in static deflection obtained for the simply supported condition. © 2023, The Author(s), under exclusive licence to Shiraz University.