Faculty Publications
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Item Investigation on Influence of Geometry on Performance of a Cavity-less Pressure Sensor(Institute of Physics Publishing helen.craven@iop.org, 2018) Mathias, K.A.; Kulkarni, S.M.In recent years the automobile comfort and safety greatly improved by incorporation of specialized sensors. These sensors monitor the satisfactory working of different parts of an automobile by providing timely information to the driver. Tyre inflation pressure sensor is one of the important devices whose satisfactory working will improve tyre life as well fuel economy. The present work is focussed on modeling of a Cavity-Less pressure sensor for sensing inflation tyre pressure. Dielectric soft material for the sensor is taken as Silicone rubber. The sensor is modeled using finite element technique. The influence of width to thickness ratio of dielectric material for square geometry is studied. It is observed that change in capacitance increases with the applied pressure. The highest sensitivity of 4.79 fF/kPa is obtained for a sensor with width to thickness ratio of 100. © 2018 Published under licence by IOP Publishing Ltd.Item Experimental investigation on dielectric properties of composites using Taguchi technique(Elsevier Ltd, 2020) Manohar Shankar, B.S.; Mathias, K.A.; Kulkarni, S.M.Flexible composites find applications as dielectric elastomers. These composites are used as actuators and sensors. Solid silicone rubber-conductive filler composites are promising candidates for above applications. They are fabricated using compression moulding and evaluated for their dielectric properties, using Taguchi design of experiments. The influence of factors such as filler and curing agent loading, mixing time, curing temperature on the dielectric properties are presented. Permittivity increased to 14.1 and dielectric loss increased to 1.27 for the conductive filler loading of up to 12 parts per hundred rubber, while still being in insulator regime. © 2019 Elsevier Ltd. All rights reserved.Item Influence of filler and processing parameters on the mechanical properties of dielectric elastomer composites(Elsevier Ltd, 2020) Manohar Shankar, B.S.; Mathias, K.A.; Kulkarni, S.M.Dielectric elastomer composites are used as actuators and sensors. They convert electrical energy directly into mechanical energy and vice versa. Conductive and dielectric fillers are added to elastomers in order to improve its permittivity, thereby altering its mechanical properties. This study investigates the effect of conductive filler and processing parameters on the mechanical properties of dielectric elastomer composites fabricated using solid silicone rubber as matrix and ketjenblack as conductive filler using compression moulding process. The processing parameters such as amount of curing agent, mixing time and curing temperature also influence the mechanical properties. Maximum values of Young's modulus, density and shore A hardness recorded were 25.2 MPa, 1210 kg/m3 and 86 for the present study. © 2019 Elsevier Ltd. All rights reserved.Item Influence of filler on dielectric properties of silicone rubber particulate composite material(Elsevier Ltd, 2020) Mathias, K.A.; Hiremath, H.; Manohar Shankar, B.S.; Kulkarni, S.M.This paper deals with the development of silicone rubber particulate composites filled with strontium titanate to improve dielectric properties of neat silicone rubber. The composite material is prepared by a solution casting method with three different volume percentages of the filler. The composite samples prepared are tested for dielectric properties as per standards. The influence of filler on dielectric properties of composite material is studied by testing for dielectric permittivity, loss tangent, and ac conductivity. The dielectric permittivity experimentally obtained is compared with the available empirical models. The dielectric permittivity, loss tangent, and ac conductivity of silicone rubber composite increased with the increase of volume percentage of strontium titanate. Compared to neat silicone rubber the dielectric permittivity, loss tangent, and ac conductivity of the silicone rubber composite filled with 10% volume of strontium titanate is increased by 66%, 117%, and 267% respectively. Further, the empirical models confirmed that dielectric permittivity obtained is within the limit. The microscopic study reveals that the improved dielectric properties attributed to the stronger bond between the silicone rubber and the strontium titanate particles. © 2019 Elsevier Ltd. All rights reserved.Item Experimental studies on mechanical and dielectric behavior of Glycerol filled Silicone rubber composites(IOP Publishing Ltd, 2021) Mathias, K.A.; Hiremath, H.; Kulkarni, S.M.In this study, Silicone rubber composites are prepared with Glycerol filler in three different volume fractions. The samples developed are subjected to mechanical and dielectric testing. The tensile strength increases first and later decreases with Glycerol loading whereas compression strength decreases with Glycerol loading. Modulus of elasticity in tension and compression both decreases with the increase of Glycerol loading. Dielectric permittivity, dissipation factor and conductivity are increases with the increase of Glycerol loading. The Silicone Rubber (SR) composite with 15% volume of Glycerol filler shown a maximum reduction in modulus of elasticity of 29% (in tension) and 16.8% (in compression), and maximum improvement in the dielectric permittivity of 112% compared to neat silicone rubber. The reduction in modulus of elasticity with an increase in dielectric permittivity with an increase in Glycerol loading suggests that this material is a potential candidate for materials to be used in soft dielectric sensors and actuator applications. © 2021 IOP Publishing LtdItem Study on low-frequency dielectric behavior of the carbon black/polymer nanocomposite(Springer, 2021) Hiremath, H.; Mathias, K.A.; Sondar, P.R.; Shrishail, M.H.; Kulkarni, S.M.Recently, polymer-based dielectric materials have become one of the key materials to play an essential role in clean energy production, energy transformation, and energy storage applications. The end usage is the energy storage capability because it is a trade-off between dielectric permittivity, dielectric loss, and dissipation factor. Hence, it is of prime importance to study the dielectric properties of polymer materials by adding filler material at a low-frequency range. In the present study, polydimethylsiloxane/carbon black nanocomposites are prepared using the solution cast method. The dielectric properties, such as dielectric constant, dielectric loss, and dissipation factors due to the concentration of filler particles and low-frequency effect on the nanocomposites, are examined. Also, different empirical models are used to estimate the dielectric permittivity of polymer nanocomposites. The low-frequency range of 100 Hz to 1 MHz and the effect of varying volume fractions of carbon black show a significant change in the dielectric properties. It is found that the nanocomposites have a higher dielectric permittivity than the base polymer material. It is also observed that an increase in filler concentration increases the dielectric permittivity, which is confirmed with an empirical model. © 2021, The Author(s).Item Physico-mechanical behavior of carbon black-infused polymer composite(Springer, 2022) Hiremath, H.; Rajole, S.; Sondar, P.R.; Mathias, K.A.; Kulkarni, S.M.This article deals with the development of polymer composites by incorporating carbon blacks (CBs) into polydimethylsiloxane (PDMS) matrix material for improving the mechanical and physical properties of the polymer composites. CBs of nano-size were used as filler material in varying volume percentages (5–25%), and the polymer composite was processed by solution casting method. Density, elastic modulus and hardness were measured in order to study the effect of the CB-reinforced PDMS matrix. Experimentally obtained mechanical properties were then compared with the standard empirical model. Density of the polymer composite was increased by five times as compared to the pure polymer material. With the increase in volume percentage of CB, both hardness and elastic modulus of the polymer composites were enhanced. Scanning electron microscope images of the composite material showed uniform distribution of CBs, implying strong binding with the matrix material, which attributed to improved mechanical properties. © 2021, Indian Academy of Sciences.