Conference Papers
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Item Investigation of static and dynamic properties of cenosphere reinforced polymer matrix composite beams(American Institute of Physics Inc. subs@aip.org, 2019) Bharath, J.; Joladarashi, S.; Nagiredla, S.; Kumar, H.Polymer Matrix Composites (PMC) plays a conspicuous role in engineering application. Cenosphere reinforced polymer matrix composite has higher strength, stiffness, lesser density and also saving in cost. These particulate composites are manufactured to meet several structural requirements. Thus there is a need to study their static and dynamic properties. In this work polymer epoxy polymer composites reinforced with cenosphere are fabricated and their static and dynamic properties are analyzed. Experimental investigation involves fabrication of specimen of polymer matrix reinforced with cenosphere by varying volume fractions of 25%, 30%, 35%, and 40%. Tensile and compressive properties are tested on UTM as per ASTM standard. Microstructures of composites are assessed with SEM and also Model analysis of cantilever beam is performed as per ASTM standard in Engineering Data Management System (EDM 7.0) of Crystal Instruments to study variation of natural frequency in each case. The natural frequency results are compared with the commercially available ANSYS FE software by assigning the material propertied obtained by static analysis. Thus effects of volume fraction of cenosphere on static and dynamic characteristics of particulate composites are studied. © 2018 Author(s).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 Vibration Analysis of Composite Viscoelastic Core Sandwich Beam Using Active Control Techniques(Springer Science and Business Media Deutschland GmbH, 2024) Raghavendra, P.; Gatty, A.S.; Rajesh, H.; Deepak, T.N.; Rawal, Y.; Nagiredla, S.; Joladarashi, S.Vibration control is swiftly advancing in research, with diverse techniques being investigated to minimize detrimental vibration levels. Compared to metallic alloys, composite materials offer superior material properties while being lightweight. The main objective of this study is to develop active control techniques on Carbon/Glass Epoxy-reinforced composite sandwich beams with viscoelastic core using Proportional Integral Derivative (PID), Linear Quadratic Regulator (LQR), and Linear Quadratic Gaussian (LQG) Controllers. The approach involves conducting an experiment to obtain the Transient Response of the beams subjected to free vibration, which is then utilized to obtain the Transfer Function and State Space variables. MATLAB-Simulink obtained transfer function is used for implementing controllers to actively attenuate vibrational amplitudes and settling time. The outcomes reveal a significant reduction in settling time and vibrational peak amplitudes. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.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.