Browsing by Author "Hiremath, S."

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Comparative study on filament wounded and laminated GFRP composites for tensile characterization
(2019) Biradar, S.; Joladarashi, S.; Rajole, S.; Hiremath, S.; Kulkarni, S.M.
The demand of composite materials has increased tremendously in various industries such as processing industries in making tanks used to process chemicals, in commercial and domestic application such as to LPG cylinders, in automobile industries like in case of car bodies, fuel tanks, aerospace industries, where fuselage wings, landing gears, doors and many other parts of aircraft. The current demand for composites is mainly due to high strength to weight ratio. Hence, we need to understand criticality in the design of composite products. In this paper primarily focused on GFRP for pressure vessels. Hence in this work an initial study was done to compare tensile properties of filament wounded GFRP test coupons with laminated GFRP test coupons which are cut as per ASTM D3039, both these types of samples are fabricated by using glass fiber direct rovings of 2400TEX. Tensile testing samples are prepared by directly cutting test coupons from fabricated vessel and whereas in case of laminated GFRP specimen are cut using hand cutting tool. The obtained results are further compared with analytical results. From comparative study, it is found that there exists considerable difference between experimental and theoretical results for tensile strength and tensile modulus in case of specimens prepared from GFRP pressure vessel. The variation in results is mainly due to presence of void content, poor interfacial bonding between fiber and matrix, fiber fragmentation, improper spacing between fibers, the presence of all these possible defects are justified by fractography study of failed samples in a scanning electron microscope. Hence from fractography study it is clearly justified that why there is least percentage error in tensile properties of laminated composites. � 2018 Author(s).
Comparative study on filament wounded and laminated GFRP composites for tensile characterization
(American Institute of Physics Inc. subs@aip.org, 2019) Biradar, S.; Joladarashi, S.; Rajole, S.; Hiremath, S.; Kulkarni, S.M.
The demand of composite materials has increased tremendously in various industries such as processing industries in making tanks used to process chemicals, in commercial and domestic application such as to LPG cylinders, in automobile industries like in case of car bodies, fuel tanks, aerospace industries, where fuselage wings, landing gears, doors and many other parts of aircraft. The current demand for composites is mainly due to high strength to weight ratio. Hence, we need to understand criticality in the design of composite products. In this paper primarily focused on GFRP for pressure vessels. Hence in this work an initial study was done to compare tensile properties of filament wounded GFRP test coupons with laminated GFRP test coupons which are cut as per ASTM D3039, both these types of samples are fabricated by using glass fiber direct rovings of 2400TEX. Tensile testing samples are prepared by directly cutting test coupons from fabricated vessel and whereas in case of laminated GFRP specimen are cut using hand cutting tool. The obtained results are further compared with analytical results. From comparative study, it is found that there exists considerable difference between experimental and theoretical results for tensile strength and tensile modulus in case of specimens prepared from GFRP pressure vessel. The variation in results is mainly due to presence of void content, poor interfacial bonding between fiber and matrix, fiber fragmentation, improper spacing between fibers, the presence of all these possible defects are justified by fractography study of failed samples in a scanning electron microscope. Hence from fractography study it is clearly justified that why there is least percentage error in tensile properties of laminated composites. Â© 2018 Author(s).
Effect of alkaline treatment on mechanical properties of natural fiber-reinforced composite
(Korean Society of Mechanical Engineers, 2024) Sangamesh, R.; Hiremath, S.; Biradar, S.; Kumar B, S.; Sondar, P.; Vishwanatha, H.M.
Natural fiber-reinforced composites are gaining popularity as eco-friendly alternatives to conventional plastics across various industries. This study investigated the fabrication of composites using areca leaves as the reinforcing filler material within an epoxy matrix. The composites were prepared using the hand-layup technique, with different weight fractions of fibers. Before composite fabrication, the areca leaves were treated with NaOH solution. A comprehensive set of tests, including tensile, compression, flexural, impact, and erosion tests, was conducted on these composites to evaluate their mechanical properties. The results showed that untreated composites exhibited superior performance in tensile (39 MPa) and compression tests (59 MPa with 45 % fiber content), while NaOH-treated composites performed better in flexural (64–67 MPa) and impact tests (21 kJ/m2 at higher fiber content). Erosion testing revealed that composites with lower filler concentrations demonstrated improved wear resistance compared to those with higher filler content, with erosion rates significantly influenced by sand concentration and particle size. These findings were supported by fracture surface analysis using scanning electron microscopy (SEM). This study provides valuable insights into the potential of areca leaf-reinforced composites as sustainable materials for various applications. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2024.
Erratum to: Effect of alkaline treatment on mechanical properties of natural fiber-reinforced composite (Journal of Mechanical Science and Technology, (2024), 38, 12, (6597-6605), 10.1007/s12206-024-1117-6)
(Korean Society of Mechanical Engineers, 2025) Sangamesh, R.; Hiremath, S.; Biradar, S.; Kumar, S.; Sondar, P.; Vishwanatha, H.M.
[No abstract available]
Influence of conductive and dielectric fillers on the relaxation of solid silicone rubber composites
(Institute of Physics Publishing helen.craven@iop.org, 2019) Manohar Shankar, B.S.; Hiremath, S.; Kulkarni, S.M.
Flexible dielectrics possessing high permittivity and low loss are desirable for many electromechanical transduction applications. Solid silicone rubber composites are promising materials for electromechanical applications. These composites are fabricated using high-temperature vulcanization process, with various amounts of conductive, dielectric and conductor-dielectric filler and processing parameters. Dielectric and conductivity relaxations of these composites are investigated using dielectric spectroscopy in the 20 Hz-2 MHz frequency range at room temperature. Dielectric relaxations of dielectric filler composites show different behaviour compared to conductive and conductive - dielectric filler composites even with the same filler loading. All composites show increased permittivity at lower frequencies. The maximum permittivity of 46, 5.8 and 46 at 20 Hz was attained for the conductive, dielectric and conductive-dielectric composites respectively at similar filler loadings. The composites follow the AC universality law with exponents in the range of 0.82 to 1.02. The conductive filler is more reinforcing than dielectric filler as seen from the variation of Young's modulus with filler type. Uniform dispersion of fillers is observed for all the three composites. © 2019 IOP Publishing Ltd.
Investigation on dielectric properties of PDMS based nanocomposites
(Elsevier B.V., 2021) Hiremath, S.; Kevin, A.M.; Manohar, S.B.S.; Kulkarni, S.M.
Polymer nanocomposites have recently been used in applications for energy storage, sensors, and actuators. The polymer materials are gaining dielectric properties such as dielectric permittivity, electrical modulus, and conductivity. In the present study, nanocomposite material is prepared by a solution cast method incorporating carbon black particles into polydimethylsiloxane. The dielectric properties of PDMS/CB nanocomposites are investigated over broad frequency using an impedance analyzer. The polymer nanocomposite's dielectric permittivity is evaluated using the various empirical models available in the literature. Compared with other methods the Wiener model is very similar to the experimental findings. For the frequency range of 100 Hz-100kHz, the frequency-dependent and independent dielectric response was observed. Nanocomposite dielectric permittivity is improved marginally with the reinforcement of carbon black particles. The nanocomposite dielectric loss moves to the higher frequency, although the losses are small. It is proved that electrical modulus can reduce the effect of polarization of electrodes. Nanocomposite AC conductivity exhibits strong frequency dependence particularly in the higher frequency region of the vicinity. This behavior obeys the power law at critical frequency, which reveals the process of relaxing conductivity. The PDMS/CB nanocomposites power-law exponent is within a range of 0.48–0.57. Eventually, empirical and experimental inspections are the basis framework for designing electronic devices based on polymers. © 2020 Elsevier B.V.
Mode-I fracture behaviour of aramid/glass-epoxy interply hybrid composites
(SAGE Publications Ltd, 2025) Kanakannavar, S.; Biradar, S.; Hiremath, S.; Rajole, S.; Pitchaimani, J.; Kulkarni, S.M.; Goh, K.-L.
This article presents the influence of hybridisation of aramid and glass fibre woven fabric on fracture toughness (KIC) of the composites. Experiments using single-edge-notched-bending (SENB) were conducted to investigate the hybridisation effect on the Mode I fracture toughness specimen of aramid/glass laminates. The results revealed that the aramid epoxy composites yielded the highest KIC, followed by aramid/glass epoxy hybrid composites, and finally, glass epoxy composites, which exhibited the lowest KIC. Fracture micrographs of the hybrid composites showed similar fracture patterns – fibre pullout, fibre rupture and matrix rupture – to those of the aramid and glass epoxy composites. The mechanical properties of the hybrid composites being inferior to those of the aramid epoxy composites suggest that there is no advantage in using glass fibres to partially replace aramid fibres in achieving hybrid composites. © The Author(s) 2025
Modelling and analysis of polymer diaphragms for micro sensing and actuation
(2019) Sushmita; Hiremath, S.; Kulkarni, S.M.
Micro sensors and actuators have potential applications in the domains like biomedical, energy harvesting and MEMS. The thin diaphragm as a primary micromechanical element is commonly seen in most of these systems. In recent days polymer-based diaphragms are being used instead of metallic diaphragms as they are more compliant, biocompatible and economical to process. Among polymers, Polydimethylsiloxane (PDMS) is by far the most widely used polymer. Fabrication and prototyping of microfluidic chips is a major area where PDMS is used. PDMS being bio-stable is used for biomedical applications such as drug delivery system and blood-contacting biomaterials. In the present work, the analysis is performed to investigate the behavior of PDMS films along with Parylene and Polyimide films. The deflection of the polymer diaphragms is computed using the analytical and finite element (FE) approaches. The deflection is computed considering the edges of the diaphragm to be fixed and the diaphragm subjected to uniform pressure. Three geometries (Circle, Rectangle, and Square) and three thicknesses are considered for each of the above materials. The results of the FE model and analytical computation are found to be in good agreement with each other. It is observed that the PDMS diaphragms with circular geometry exhibited larger deflection. The deflection values appear to be suitable for enhancing diaphragm performance in applications like micro pumps and energy harvesting devices. � 2019 Author(s).
Modelling and analysis of polymer diaphragms for micro sensing and actuation
(American Institute of Physics Inc. subs@aip.org, 2019) Sushmita; Hiremath, S.; Kulkarni, S.M.
Micro sensors and actuators have potential applications in the domains like biomedical, energy harvesting and MEMS. The thin diaphragm as a primary micromechanical element is commonly seen in most of these systems. In recent days polymer-based diaphragms are being used instead of metallic diaphragms as they are more compliant, biocompatible and economical to process. Among polymers, Polydimethylsiloxane (PDMS) is by far the most widely used polymer. Fabrication and prototyping of microfluidic chips is a major area where PDMS is used. PDMS being bio-stable is used for biomedical applications such as drug delivery system and blood-contacting biomaterials. In the present work, the analysis is performed to investigate the behavior of PDMS films along with Parylene and Polyimide films. The deflection of the polymer diaphragms is computed using the analytical and finite element (FE) approaches. The deflection is computed considering the edges of the diaphragm to be fixed and the diaphragm subjected to uniform pressure. Three geometries (Circle, Rectangle, and Square) and three thicknesses are considered for each of the above materials. The results of the FE model and analytical computation are found to be in good agreement with each other. It is observed that the PDMS diaphragms with circular geometry exhibited larger deflection. The deflection values appear to be suitable for enhancing diaphragm performance in applications like micro pumps and energy harvesting devices. Â© 2019 Author(s).
Modelling and Comparative Analysis of Epoxy-Fly-Ash Composite with Alloys for Bracket Application
(MDPI, 2022) Raghunandan, A.B.; Chiniwar, D.S.; Hiremath, S.; Sondar, P.; Vishwanatha, H.M.
The current study compares and analyses the fly-ash–epoxy composite structure with alloys for bracket applications. A dispersed reinforcement composite is created by combining epoxy and fly-ash. Three different prototypical brackets are modelled and analysed using the finite element method, and their results are compared to common alloys used in the manufacture of L-shaped brackets. The mechanical properties of the composite material are calculated using a rule of mixtures, and the properties of the composite material are modified by changing the percentage composition of fly-ash. Based on equivalent stress and total deformation, all geometrical models are analysed and compared. The analysis results appear to be appropriate for broadening the scope of the application of epoxy-based composites for small-scale and large-scale applications. The results also show that the composite material can be used to make a variety of structural elements with high design complexity, such as bulkheads and other structural components. © 2022 by the authors.
Modelling of single and multi-port manifolds and studying the influence of structural and thermal behaviour on exhaust manifolds used in automotive applications
(Springer-Verlag Italia s.r.l., 2024) Sangamesh, R.; Twinkle, R.; Chiniwar, D.S.; Vishwanatha, H.M.; Sondar, P.; Hiremath, S.
With the new pollution control rules and surging requirements for the increase in efficiency of the internal combustion engines, designing the exhaust manifold has become a growing area of interest. The present work focuses on modelling the multi-end exhaust manifold and comparing it with the single-end exhaust manifold. Both the structural and thermal analyses are carried out using the finite element method. Along with the modified design, various materials such as mild steel, cast iron, stainless steel and medium carbon steel are also evaluated for their structural and thermal behaviour. It is found that the multi-end exhaust manifold performs better in terms of better stress and temperature distribution in comparison to the single-end exhaust manifold. The magnitude of the stress experienced by multi-end exhaust manifolds is 20 MPa lesser than single-end exhaust manifolds. However, the change in material has a marginal effect in terms of stress and temperature distribution. © The Author(s) 2022.
Numerical analysis of polymer composites for actuation
(International Information and Engineering Technology Association, 2020) Hiremath, S.; Sangappa, V.; Rajole, S.; Kulkarni, S.M.
The design of a polymer composite actuator is essential for micro and nano applications. Thus, the composite material may deform or deflects as specific stimuli are applied, such as heat, electrical, light source, etc. The deformation of the composite material is caused by the type of stimulus applied. Hence, while it is heated, the expansion takes place quickly, and the heating is shut down, the material shrinks very slowly. In the present investigation, this phenomenon is mainly studied in the actuation of composite beams. Numerical analysis of carbon black filled polymer composite beam expansion, and contraction is being analyzed in this research. The structure of the beam has been created, and the composite properties are incorporated into the beam, and the uniform heat source is applied on to the surface of the beam. The heating and cooling of the composite material predict the increase and decrease in the temperature of the beam. The numerical analysis of the temperature-dependent expansion and contraction of the composite beam has been carried out successfully. An increase in temperature is observed to signify the slight expansion in the composite beam, whereas the contraction of the composite beam takes a longer time to reach room temperature. Also, the increase in the content of the filler leads to a decrease in the expansion of the composite beam. The numerical simulation of the polymer composite thus provides a solid platform for the experimental study of thermal actuators. © 2020 Lavoisier. All rights reserved.
Photomechanical actuation of polydimethylsiloxane/carbon black nanocomposite
(Institution of Engineering and Technology jbristow@theiet.org, 2020) Hiremath, S.; Kulkarni, S.M.
Materials such as carbon black (CB), carbon nanotube, graphene, etc. have been found to deform on exposure to the light source. Introducing these materials into polymers could convert them to photo-responsive composites. This is demonstrated by the experiment in which polydimethylsiloxane (PDMS) polymer containing CB nanofiller composites is prepared, and its photomechanical actuation from exposure to IR light source is recorded using a laser displacement sensor. The particle size analysis reveals the size of the CB, which is verified by the dynamic light scattering method. The UV-vis-IR spectrophotometer study shows that an increase in the light absorbance capacity of nanocomposites compared to the plain polymer. The PDMS/CB nanocomposite beam exhibited a significant deformation compared to plain PDMS. Deformation of the order of 10-11 mm is observed for a given IR source. The deformation found to have good repeatability but with some thermal hysteresis in cyclic actuation and de-actuation. © 2020 Institution of Engineering and Technology. All rights reserved.
Processing and investigation of mechanical characteristics on the polydimethylsiloxane/carbon black composites
(Institute of Physics Publishing helen.craven@iop.org, 2019) Hiremath, S.; Sangamesh, R.; Kulkarni, S.M.
The mechanical adaptability of elastomers has enormous potential in fields such as energy harvesting, micro electro mechanical system (MEMS), sensor, and actuator. A significant issue is to improve the mechanical features of the elastomeric base material by incorporating an appropriate filler. The elastomer Polydimethylsiloxane (PDMS) is reinforced with carbon black (CB) particles that affect mechanical characteristics (Tensile strength, compressive strength, tear strength, etc) and that have a critical impact on the efficiency of the device. The current research examines the mechanical characteristics of plain PDMS with a concentration of CB filler between 5% and 25%. A solution casting method is used to prepare the composite substrate and investigate the impacts of CB loading performance on tensile, compression, tear, and hardness testing. The outcome shows an improvement in mechanical characteristics due to CB material for Young's module as 1.64-3.84 MPa, ultimate tensile strength as 1.86-4.8 MPa, 3.67-4.81 MPa compressive module with the same compressive strength up to 40 percent strain. The tear strength of the PDMS/CB composites is improved by ?111 percent at 25 percent volume fraction of the CB. The composite hardness of PDMS/CB increases by about 30 percent of the plain PDMS material. Continuing with this, Additional mechanical characteristics of PDMS/CB composites on shear and bulk modules are reported. © 2019 IOP Publishing Ltd.
Progression and characterization of polydimethylsiloxane-carbon black nanocomposites for photothermal actuator applications
(Elsevier B.V., 2021) Hiremath, S.; H, S.M.; Kulkarni, S.M.
The new development of polymer-based actuators triggers the progress of nanocomposites. Polymer materials are currently used in sensors, microfluidic devices, electrical and thermal actuators, and energy harvesting applications due to ease of availability, excellent tolerable properties, and customizable properties. The polymer-based nanocomposite can be driven by various stimuli, which is the actuator's emerging field. Thus, photothermal actuation is a thurst area of research transforming light energy into mechanical energy through the polymer material. The photo-responsive material can be prepared and tested for photo-actuation by incorporating the nanoparticles into the polymer. The present work focuses on developing polydimethylsiloxane (PDMS) and carbon black (CB) nanocomposite. The objective here is to investigate the photothermal actuator's performance by illuminating the infrared (IR) light source and studying its most influential characteristics, such as absorbance, thermal conductivity, and the thermal expansion coefficient. The PDMS / CB nanocomposite absorbs the IR light and then increases temperature, which is finally transformed into a beam deflection. Responses are measured as a result of time deflection using the Laser displacement sensor. It is noted that the deflection of the nanocomposite beam is linearly increased during illumination with light while it is exponentially decreasing when the light is turned off. The proposed polymer nanocomposite is approximately deflected by 9 mm in the duration of 16 s duration. Furthermore, the experimental deflection of the photothermal actuator is very close to theoretical results. The nanocomposite PDMS / CB reveals that there is an increase in absorbance by increasing the filler content. The nanocomposite conductivity is 35.2 % higher than the base material. As well, the thermal expansion coefficient decreases with an increase in carbon black content. The photothermal actuator's development is an ongoing process in which the material parameter, actuator geometry, and many more are modified. As a result, the photothermal bending performed can provide a means for various light-driven applications. © 2020 Elsevier B.V.
The influence of hygrothermal aging on the hoop tensile strength of glass fiber wound polymer composites fabricated via filament winding technique
(Institute of Physics, 2024) Biradar, S.; Hiremath, S.; Vishwanatha, H.M.; Joladarashi, S.; Kulkarni, S.M.
The study investigates the impact of moisture environment treatment, on the hoop tensile strength (HTS) of glass fiber-reinforced polymer (GFRP) composites, through hygrothermal aging. GFRP cylinders were fabricated with varied parameters—volume fraction, winding angle, and stacking sequences using a filament winding machine. The fabricated samples are subjected to hygrothermal aging using seawater and tap water with oil at 80 °C for 1080 h (45 days). The HTS tests were performed on unaged and aged samples. There was a reduction in HTS for aged samples which is attributed to heat, seawater contamination, and oil. The highest and lowest HTS values recorded are 402.9 MPa and 118.3 MPa for unaged and tap water with oil-aged samples respectively. HTS in aged samples is compared with unaged samples. The study opens up avenues in identifying the best-suitable combination for retaining HTS under various aging conditions. © 2024 The Author(s). Published by IOP Publishing Ltd.