Browsing by Author "Kumar, G.C."

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Analysis of spur gears drilled with radial holes on teeth surface for effective weight reduction
(Springer Science and Business Media Deutschland GmbH, 2025) Sutar, S.S.; Kumar, G.C.; Doddamani, M.
Optimizing the geometry for efficient material utilization and gear weight reduction involves strategically removing material from gear teeth. This present study examines the stresses induced in the gears featuring radial holes within the gear tooth focused on lightening the weight of conventional gears. Radial holes are introduced at varying depths from the top of the gear tooth. The analysis uses ANSYS to assess the stresses in a conventional gear tooth and also the tooth with radial holes. Examining stress magnitudes near the gear root under similar loading and boundary conditions is critical and interesting. A complementary photoelastic approach is implemented, and stress distribution in these gears is confirmed to ensure the findings of finite element analysis. This approach retains the stress distribution while achieving a notable 6.7% reduction in volume compared to a conventional AGMA spur gear. Moreover, these radial holes are envisaged to contribute to adequate gear lubrication and cooling through fluid motion. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.
Biocompatible Nanohydroxyapatite from Cuttlefish Bone by Mechanochemical Method for Bone Tissue Engineering Applications
(Springer, 2024) Jalageri, M.B.; Kumar, G.C.
Hydroxyapatite was synthesized from coral cuttlebone using a mechanochemical method in this study. The synthesized material was characterized using various techniques to determine its phases and functional groups. Field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis TGA were employed. FESEM analysis revealed an onedimensional nanorod morphology of the developed material. X-ray diffraction (XRD) confirmed that the primary phase was hydroxyapatite, with slight traces of tricalcium phosphate detected after calcination at 800 °C. The FTIR spectra exhibited peaks corresponding to phosphate and hydroxyl groups. At the same time, TGA results indicated the absence of any organic phase. Furthermore, the synthesized hydroxyapatite displayed excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria. Cytocompatibility tests with MG63 fibroblast cells demonstrated that these materials are both antimicrobial and biocompatible, making them suitable for various biomedical applications. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Comparison of Stress Distribution of Graphene-Based Bioactive Material for Zirconia and Titanium by Applying Orthotropic Properties: A Finite Element Analysis
(Springer Science and Business Media Deutschland GmbH, 2024) Singh, R.K.; Verma, K.; Kumar, G.C.
This study employs finite element analysis to examine stress distribution at the boneâ€“implant interface in graphene-based dental implants. Four implant models, encompassing titanium and zirconia with and without graphene coating, are assessed under axial and oblique loading. Considering their anisotropic nature, bone tissues are simulated as orthotropic, while implants are treated as homogeneous and isotropic. The study utilizes one-way ANOVA and Kruskalâ€“Wallis tests for statistical analysis to compare stress distribution among implant groups. Results indicate superior von Mises stress distribution in graphene-based implants (A2 and A4) compared to the pure material group. The incorporation of graphene coating significantly reduces implant stresses under axial and oblique loads compared to titanium and zirconia. In conclusion, the study underscores the potential benefits of graphene-based implant models in optimizing stress distribution at the boneâ€“implant interface, emphasizing the importance of suitable implant models and biomaterial selection for enhanced dental implant performance. Â© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
Dynamic Mechanical Analysis and Thermal Stability of Neem Wood Veneer Plastic Composites
(Elsevier Ltd, 2019) Nagamadhu, M.; Vijay Kumar, S.; Ravi Kumar, S.; Suraj, R.; Kumar, G.C.
The neem wood veneer is used as core materials in many of the wood structural applications. In this research work, neem wood polymer composite (NWPC) were prepared to understand the effect of weight fraction, stacking sequence, and interfacial bonding between neem wood veneer and epoxy material. NWPC were prepared conventional compression molding and Thermo-mechanical properties of wood epoxy composite samples were investigated by the dynamic mechanical analyzer over the temperature range from 30 to 180Â°C. Storage modulus (G') and Loss modulus (G") of NWPC samples exhibited significant effect with respect weight fraction of wood veneer. Similarly epoxy has good interfacial bonding agent to enhance the strength of multilayered wood polymer composites. However, the stacking sequence having major changes in dynamic mechanical properties, G' & G" increases along the wood fiber direction with negligible load bearing capacity in transfers direction. By changing the orientation of the wood veneer properties improved in both the direction. Additionally, scanning electron microscopy (SEM) evidently shows the interfacial bonding efficiency. Â© 2019 Elsevier Ltd.
Dynamic study of composite material shaft in high-speed rotor-bearing systems
(Inderscience Publishers, 2019) Gonsalves, T.H.; Kumar, G.C.; Ramesh, M.R.
In this work the composite material shaft in high-speed rotor-bearing systems is analysed to achieve better rotor dynamics along with the effect of internal damping of the composite shaft. The pioneering studies on rotating composite shaft and internal damping are revisited to evaluate its effects on rotor dynamics of high-speed rotor-bearing systems. Two practical rotor-bearing systems are selected to study their suitability for composite shaft application where the composite material is used in the cold section while the existing steel alloy is retained in the hot section as well as at the ends. The rotor dynamic analysis shows significant improvements in rotor dynamics of one of the rotor-bearing systems where the first lateral mode changes to desirable rigid mode from flexure mode shape of existing metallic shaft rotor-bearing system. The frequency values of second and third modes also increase above the operating speed indicating a clear advantage in rotor dynamics. © © 2019 Inderscience Enterprises Ltd.
Effect of drilling parameters on Neem wood veneer epoxy composites using grey relational analysis
(Elsevier Ltd, 2019) Jaiprakash, M.; Nagamadhu, M.; Karthikeyan, K.; Kiran; Shariff, M.; Kumar, G.C.
In recent trend the composites based wood are replacing the normal wood and other materials in various fields. The wood composites have cosmic properties like cheaper in cost, denser, free from defect, they can be machined in any way to make desired output product. This paper is all about investigation of wood properties and its behavior for drilling process. Drilling is one of the universal machining process that being carried out in the world.The purpose of drilling is to remove the excess of material from the work piece (specimen) to produce a hole and drilling is the primary process that need to be carried on the specimen to perform other machining operation (boring, reaming and tapping) as drilling got various level of importance in different applications, studying about drilling process and its parameter on different materials is important. This paper is all about the analysis of different drilling parameters such as feed rate (mm/min), spindle speed (rpm), Drill diameter on the quality of drilled hole. To study these factors Grey relation technique and Taguchi analysis is implemented. The result shows that feed rate is the major influencing parameter when compared to other cutting parameter and by selecting the optimal value,the quality of the drilled hole can be improved. Â© 2019 Elsevier Ltd.
Enhanced Cartilage Regeneration: Chemical, Mechanical, and In Vitro Analysis of Innovative TiO2-Reinforced PVA Implants
(American Chemical Society, 2025) Santosh Kumar, B.Y.; Isloor, A.M.; Kumar, G.C.; Prashanth, S.; Penupolu, A.
This study focuses on developing a synthetic, biocompatible graft for treating cartilage lesions. One-dimensional titanium dioxide nanotubes (TNTs) were incorporated into poly(vinyl alcohol) (PVA) hydrogel and processed using freeze-drying without chemical surfactants. Upon optimization of the composition, it was found that the incorporation of TNT altered the biomechanical properties without causing any adverse physiological effects. Annealing treatment further enhanced mechanical strength and energy dissipation, promoting elasticity. The hydrogel with 2 wt % TNT achieved maximum mechanical strength and the storage modulus values indicated elastic dominance, and biotribological tests showed cartilage-like frictional response via hydrodynamic lubrication. Against the microorganisms Escherichia coli, Staphylococcus aureus, and Candida albicans, grafts showed significant antimicrobial activity. In vitro experiments demonstrated that these nanocomposite hydrogels supported adhesion, proliferation, and upregulation of cartilage-specific gene expression in human mesenchymal stem cells hMSCs. This suggests potential for promoting hMSC chondrogenic differentiation and accelerating cartilage regeneration. © 2025 The Authors. Published by American Chemical Society.
Epoxy-based composites with size-fractionated waste Areca sheath: an experimental investigation on the macroscopic and vibrational properties
(Gruppo Italiano Frattura, 2025) Varghese, L.; Kumar, G.C.
The use of Areca sheath in developing a newer composite material is proposed in this article. The Areca sheath particulates are extracted by pulverizing long sheaths into different sizes of particulates and are reinforced into the epoxy to process the composites. The study evaluated these composites' macroscopic and vibrational properties, revealing that those with coarse particulates demonstrated superior tensile and flexural strengths, impact strength, hardness, and natural frequency. Notably, the coarse epoxy composite with a 10% weight fraction of particulates exhibited tensile strength and modulus values of 24 MPa and 1050 MPa, respectively. These findings suggest that incorporating a 10% weight fraction of coarse Areca sheath particulates into epoxy resin significantly enhances the composite's macroscopic and vibrational properties, making it a promising material for various building applications like Partition panels, Ceiling Panels, and similar applications. © 2024, Gruppo Italiano Frattura. All rights reserved.
Finite Element Analysis for Material Optimization of a Spur Gear by Radial Holes
(Springer Science and Business Media Deutschland GmbH, 2022) Sutar, S.; Kumar, G.C.; Doddamani, M.
Use of advanced materials in gear manufacturing lead to the best use of the material is achieved by geometric optimization, which uses less material. Removal of the material from gear makes lighter weight gear, and the simulation study helps in understanding their effects on stress distribution. This present research work focuses on removing material from the gear tooth for developing lightweight gears. Circular holes are introduced radially through the gear tooth and holes of 1.5Â mm diameter created from top land of the gear tooth with varying depth from 5 to 20Â mm. This leads to a volume reduction of 2.49% to a maximum of 12.451% as compared to no radial hole on gear. The analysis of CAD models created in CREO software of pinion and gear assembly is carried out in Ansys Workbench 17.2. Stresses in gear proposed are compared with the gear without a hole. The magnitude of stresses at the roots for both pinion and gear is observed and discussed. Â© 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Hydroxyapatite Reinforced Polyvinyl Alcohol/Polyvinyl Pyrrolidone Based Hydrogel for Cartilage Replacement
(MDPI, 2022) Jalageri, M.B.; Kumar, G.C.
Polyvinyl alcohol (PVA) and Polyvinyl Pyrrolidone (PVP) hydrogels are desirable biomaterials for soft tissue repair and replacement. However, the bio-inertness and poor cell adhesive potency of the PVA and PVP hinder the wide range of biomedical applications. In the present work, PVA and PVP were blended with a one-dimensional hydroxyapatite nanorod (HNr), and PVA/PVP/HNr composite hydrogel was synthesized by the freeze-thaw process. The developed hydrogels were characterized by Scanning Electron Microscope (SEM). The bio-ceramic nanohydroxyapatite content was optimized, and it was found that reinforcement improves mechanical strength as well as bioactivity. The compression strength values are 2.47 ± 0.73 MPa for the composite having 2 wt% of nanohydroxyapatite. The storage modulus was much higher than the loss modulus, which signifies the elastic dominancy similar to cartilage. Besides, the antimicrobial activity of nanohydroxyapatite reinforced PVA hydrogel towards bacterial species, Escherichia coli (E. Coli), Staphylococcus aureus (S. aureus) was satisfactory, and the in vitro biocompatibility response towards Human Mesenchymal stem cells(hMSC) after 72 h of culture confirms nanohydroxyapatite reinforced PVA/PVP hydrogels are the promising alternatives for next-generation cartilage substitutes. © 2022 by the authors.
Influence of extender on Thermo-mechanical Properties of melamine-urea-formaldehyde [MUF] for wood adhesive applications
(Elsevier Ltd, 2019) Nagamadhu, M.; Ravi Kumar, S.; Suraj, R.; Manjunath Iyer, K.B.; Kumar, G.C.
Now a day's many researchers are trying to build alternative materials for raw wood, by using wood composite materials as an alternative. However, in wood polymer composites major limitations on adhesive materials and its bonding strength effect with economy. In this paper melamine-urea-formaldehyde (MUF) wood adhesive properties were determined over a range of temperature. MUF prepared by considering 1:2.3 weight ratio of urea to the formalin, at 90Â°C and pH is adjusted to 7.5-8.0 and second urea is added at certain time interval to reduce the formaldehyde emission. MUF has certain properties like flow time, viscosity, solid content, water tolerance, shelf life which is calculated by the observation made. The cost of MUF adhesive can be controlled by adding extender (Maida). As wood polymer composites subjected to over a range of temperature. It's necessary to understand the thermo-mechanical properties of MUF reinforced with Maida as an extender using Dynamic Mechanical Analyzer (DMA). The DMA gives in-phase component like storage modulus, loss modules and tan delta. The results show that storage modulus increases with adding extender even at higher temperature, these shows that by adding extender MUF resist the intermolecular motion. The damping factors were found to be increases by adding extender. Tan delta of MUF exhibiting narrow peak with higher magnitude indicates more energy dissipates, by adding the extender it reduces. The adding extender Maida (MD) water absorption decreases, this shows better MUF having better bonding with extender. Â© 2019 Elsevier Ltd.
Optimizing dental implant design parameters through orthotropic properties of bone: a DOE-based approach
(Springer-Verlag Italia s.r.l., 2025) Singh, R.K.; Verma, K.; Kumar, G.C.; Doddamani, S.
Dental implant research has provided insights into the effects of thread design and occlusal loading rate on stress distribution within implants and adjacent bone structures. However, ongoing advancements in materials necessitate further investigation to optimize implant performance through a thorough understanding of design parameters. This study developed a comprehensive three-dimensional CAD model of dental implants, incorporating cortical and cancellous bone, crown, and various thread types (V type, buttress, and trapezoidal threads). Multiple thread design parameters (pitch, length, angle, and depth) were varied to analyze their impact on stress distribution. Taguchi's design of experiments, combined with finite element analysis, was employed to explore stress distribution around dental implants. The implant material used was Ti6Al7Nb alloy, comprising 90% titanium, 6% aluminium, and 7% niobium. Von Mises stresses were compared to identify the optimal design. Taguchi's analysis revealed that raising all parameters except pitch reduced implant stress. However, for trapezoidal and buttress designs, increasing pitch resulted in higher stress levels. A confirmation experiment, utilizing the developed regression equation, validated these findings. Comparative analysis between simulation and statistical results showed a close match across all cases; with an error rate of less than 10%. These findings underscore the reliability and accuracy of the research outcomes, emphasizing the significance of identified thread types and their impacts on implant stress. Further research in this area could lead to advancements in dental implant design, enhancing patient outcomes and implant longevity. © The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature 2025.
Potential of Graphene-Functionalized Polymer Surfaces for Dental Applications: A Systematic review
(Taylor and Francis Ltd., 2025) Singh, R.K.; Verma, K.; Kumar, G.C.; Jalageri, M.B.
Graphene, a two-dimensional carbon nanomaterial, has garnered widespread attention across various fields due to its outstanding properties. In dental implantology, researchers are exploring the use of graphene-functionalized polymer surfaces to enhance both the osseointegration process and the long-term success of dental implants. This review consolidates evidence from in-vivo and in-vitro studies, highlighting graphene’s capacity to improve bone-to-implant contact, exhibit antibacterial properties, and enhance mechanical strength. This research investigates the effects of incorporating graphene derivatives into polymer materials on tissue response and compatibility. Among 123 search results, 14 articles meeting the predefined criteria were analyzed. The study primarily focuses on assessing the impact of GO and rGO on cellular function and stability in implants. Results indicate promising improvements in cellular function and stability with the use of GO-coated or composited implants. However, it is noted that interactions between Graphene derivatives and polymers may alter the inherent properties of the materials. Therefore, further rigorous research is deemed imperative to fully elucidate their potential in human applications. Such comprehensive understanding is essential for unlocking the extensive benefits associated with the utilization of Graphene derivatives in biomedical contexts. © 2024 Informa UK Limited, trading as Taylor & Francis Group.
Predictive modeling of PMMA-based polymer composites reinforced with hydroxyapatite: a machine learning and FEM approach
(Gruppo Italiano Frattura, 2025) Singh, R.K.; Verma, K.; Kumar, G.C.
This research examines the mechanical characteristics of polymer composites (PMMA) that are reinforced with Hydroxyapatite (HAp), with a particular emphasis on the Elastic Modulus and Compressive Strength. The investigation employs a multifaceted approach that integrates experimental methods, micromechanical analysis, and machine learning techniques. Experimental assessments of Elastic Modulus and Compressive Strength were conducted at various HAp concentrations (5%, 15%, and 30%) and were compared with theoretical predictions derived from Representative Volume Element (RVE) and micromechanical frameworks, including Voigt and Reuss bounds. Various machine learning algorithms, such as Feedforward Neural Network (FFNN), Radial Basis Neural Network (RBNN), and Support Vector Machine (SVM), were used to predict the mechanical properties. The RBNN exhibited high accuracy (R² = 0.92; MAE = 0.05) for intermediate HAp levels (20-30%) but displayed instability at the extremes % of reinforcements values . The FFNN consistently provided lower estimates of the properties, whereas the SVM yielded robust and stable predictions that closely matched both experimental and theoretical results with the error of (2-5) % (Result value). This research highlights the effectiveness of integrating micromechanical modeling with machine learning to improve the prediction and comprehension of composite behavior, thereby offering valuable insights for the design and application of advanced materials. © 2025, Fracture Structural Integr. All rights reserved.
Processing and characterization of egg shell derived nano-hydroxyapatite synthetic bone for Orthopaedic and Arthroscopy implants and substitutes in dentistry
(Elsevier Ltd, 2023) Santosh Kumar, B.Y.; Kumar, G.C.; Shahapurkar, K.; Tirth, V.; Algahtani, A.; Al-Mughanam, T.; Alghtani, A.H.; Murthy, H.C.
The present work is focused on the nano-Hydroxyapatite (nHAp) synthesis with two different Indian breed Aseel and Kadaknath eggshells. The alloplast implants were developed through the foam replica method with polyurethane 45-PPI as a porous template. The synthesized nHAp was characterized by Field Emission Scanning Electron Microscopy (FE-SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The FE-SEM images of the nHAp showed the one dimensional clustered nanoparticles and the X-ray diffraction spectrum confirms that the major phase was hydroxyapatite with a small trace of β-tricalcium phosphate. The maximum compression strength of the sample was 5.49 ± 0.12 MPa which is in the range of the compression strength of human trabecular bone. The thermal and degradability studies results confirmed that these are highly stable and provides necessary a resorption needed for new bone tissue formation. Besides, the antimicrobial activity against tested human microbiome are satisfactory and the cell viability towards MG 63 human osteoblast-like cells provides a potential pathway for developing the nHAp implants for bone tissue engineering. © 2023 Elsevier Ltd
Study on tearing strength of woven sisal fabrics for tents and polymer composite applications
(Taylor and Francis Ltd., 2023) Nagamadhu, M.; Kivade, S.B.; Jeyaraj, J.; Kumar, G.C.; Shivaraj, B.W.; Bharath, K.N.
The use of plant fibers as a reinforcement in composites has increased daily owing to their favorable environmental considerations. Fabric properties play a significant role in alignment during composites processing, enhancing the composite properties. However, the fabric structures are formed by warp and weft yarns. These yarns are subjected to axial and shear loads, respectively. However, very limited work has been carried out on the study involving the tearing strength of the fabric. So it is necessary to study the effect of the tearing load of fabrics before converting them into composites. This paper focuses on the tearing strength of the sisal woven fabrics in both warp and weft directions. Two plain and one weftrib fabrics are prepared using sisal fibers, and their physical properties were characterized as per textile testing standards. Tear strength has been determined by Elmendorf Tear and Single Rip Tear Method by varying crosshead speeds. The result shows that woven patterns and number yarns significantly impact tearing strength. In the case of the weft rib pattern, the warp direction exhibits the highest tearing strength compared to the weft direction. Also, in the case of weftrib fabrics, the weft direction indicates better-tearing strength than another woven pattern. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.
Thermal stability and sound absorption in perforated areca sheath-epoxy composite materials
(Springer Science and Business Media B.V., 2025) Varghese, L.; Kumar, G.C.
The present work emphasizes developing epoxy composites using areca sheath particulates, focusing on improving the thermal and acoustic properties. These composites are developed using conventional methods, and followed by surface modification by different types of perforations using pin perforation techniques. The sound absorption characteristics of these specimens were evaluated using an impedance tube, while thermal stability through thermogravimetric analysis and microstructural properties were analyzed. The results indicate that composite specimens with only half of the area perforated with 1 mm diameter holes demonstrate a superior sound absorption range compared to other specimens. The influence of perforation patterns on specimen surfaces was also studied. Additionally, the thermogravimetric analysis of composites reveals that the developed materials possess significant thermal stability, making them more suitable for thermal and acoustic applications in public buildings and auditoriums than other lightweight composites. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.