Faculty Publications
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Item A novel approach to determine the thermal transition of gum powder/hydro-gels using dynamic mechanical analysis(American Institute of Physics Inc. subs@aip.org, 2018) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.The dynamic characterization of materials plays a major role in the present area. The many researchers are worked on solid materials and its characterization, it can be tested using dynamic mechanical analyzer (DMA), however, no such work on powder a semiliquid samples. The powder and liquid samples can also easily characterization as like solid samples using DMA. These powder samples are analyzed with a material pocket method which can be used to accurately determine very low levels of variation in powder properties, due to the high sensitivity of DMA to glass transitions. No such DMA studies on hydrogel and Gum powders. The gum powders are used in various applications start from food industries, pharmacy, natural gums paste, biomedical applications etc. among all this applications gum Ghatti is one of the powders using for varies applications. Around 50 milligrams of Ghatti powders are placed inside material pocket and analyzed storage modulus (G′), loss modulus (G″) and tan delta (δ). Also, understand the curing and glass transition effect using water, glycerin and superplastic from room temperature to 200°C. The result shows that storage modulus decreases with increase in temperature in pure Ghatti powder. The surprising improvement in storage modulus was found with an increase in temperature with addition of water, glycerin, and superplastic. However, loss modulus and tan delta are also having very significant influence and also shows a clear peak of the tan delta. The loss modulus results were found to be improved by adding solidifying agents, along with this water and superplastic better influence. But glycerine found to be hydrogel in nature and thermodynamic properties are much influenced by frequency. © 2018 Author(s).Item Effect of stacking sequence on mechanical properties neem wood veneer plastic composites(American Institute of Physics Inc. subs@aip.org, 2018) Nagamadhu, M.; Mohan Kumar, G.C.; Jeyaraj, P.This study investigates the effect of wood veneer stacking sequence on mechanical properties of neem wood polymer composite (WPC) experimentally. Wood laminated samples were fabricated by conventional hand layup technique in a mold and cured under pressure at room temperature and then post cured at elevated temperature. Initially, the tensile, flexural, and impact test were conducted to understand the effect of weight fraction of fiber on mechanical properties. The mechanical properties have increased with the weight fraction of fiber. Moreover the stacking sequence of neem wood plays an important role. As it has a significant impact on the mechanical properties. The results indicated that 0°/0° WPC shows highest mechanical properties as compared to other sequences (90°/90°, 0°/90°, 45°/90°, 45°/45°). The Fourier Transform Infrared Spectroscopy (FTIR) Analysis were carried out to identify chemical compounds both in raw neem wood and neem wood epoxy composite. The microstructure raw/neat neem wood and the interfacial bonding characteristics of neem wood composite investigated using Scanning electron microscopy images. © 2018 Author(s).Item 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 180°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. © 2019 Elsevier Ltd.Item 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. © 2019 Elsevier Ltd.Item 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 90°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. © 2019 Elsevier Ltd.Item Dynamic mechanical analysis of glutaraldehyde cross linked polyvinyl alcohol under tensile mode(American Institute of Physics Inc. subs@aip.org, 2019) Mohan Kumar, G.C.; Jeyaraj, P.; Nagamadhu, M.Nowadays researchers are looking out for biodegradable materials alternate to petroleum-based materials due to many global issues. Polyvinyl Alcohol (PVA) cross-linked with Glutaraldehyde (GA) polymer have found widespread applications in light-weight structures in replacement of non-biodegradable polymers. The PVA cross-linked with GA polymers were prepared using a conventional compression type molding technique. Dynamic Mechanical Analysis has been carried out to evaluate the tensile storage and loss modulus, tan delta, and elongation, in the temperature range of 25-160°C. The results exhibit improvement of thermo-mechanical properties at higher temperatures due to GA crosslinking. Experimental results indicate that the tensile storage and loss modulus were improved due to GA crosslinking. The elongation of PVA-GA decrease considerably with GA crosslinking. The shore D hardness improves with crosslinking up to 20% GA, and further marginal increase in hardness beyond 20% GA crosslinking. © 2018 Author(s).Item Short term creep behavior of neem wood veneer epoxy composites(American Institute of Physics Inc., 2023) Nagamadhu, M.; Kivade, S.B.; Vijay Kumar, S.V.; Kumar, G.C.M.Neem wood used many structural applications due to its coarse grain with interlocking fibers leads to excellent mechanical properties with a very good life. However, wood structures are exposed to various environmental conditions, so it is necessary to investigate the effect of time and temperature for different stacking sequences. This paper aims to explore the importance of time and temperature of neem wood veneer epoxy composites at various stacking sequence and interfacial bonding. The Dynamic Mechanical Analyzer used to study short term creep at a nitrogen environment using a three-point bending condition. The result shows neat neem wood veneer exhibit a higher percentage of strain as compared to neem wood epoxy composites. On the other hand, the stacking sequence having significant changes in dynamic mechanical and creep studies, storage modulus (G') & loss modulus (G'') increases along the wood fiber direction with minor load-bearing capacity in lateral direction. By varying the orientation of the wood veneer mechanical and thermo-mechanical properties improved in both longitudinal and lateral direction. © 2023 Author(s).Item Mechanical Properties of Chemical Treated Woven Banana/Polyvinyl Alcohol Composites(ICE Publishing, 2019) Gunge, A.; Kivade, S.B.; Nagamadhu, M.Present work investigates the effect of chemical treatment on mechanical properties of plain woven banana fabrics (PWBF) reinforced to polyvinyl alcohol (PVA) bio-degradable matrix composite. Woven banana fabrics are chemically treated with different percentages of concentration (0.5, 1, 2, 3 and 4%) for 4 hours at room temperature. The banana fabrics and PVA are used in the ratio of 55% and 45% weight fraction respectively. Composites are prepared using hand-layup method. The samples are tested according to different ASTM standard for tensile, flexural and impact.The results are exhibited that tensile, flexural and impact properties were found to increase with potassium permanganate (KMnO4) treatment. The 1% potassium permanganate treated fabrics shows very good mechanical properties compared to untreated, 0.5, 2, 3 and 4% treated fabrics, 1% treated fabrics gives 68.07% increment in the tensile strength of the composite compared to the untreated fabrics composite. The scanning electron microscopy (SEM) also reveals 1% treated has the better interfacial bonding between fabrics and matrix. This contributes to improvement in the mechanical properties of the composite. © 2019 ICE Publishing: All rights reserved.Item Mechanical and tribological behavior of woven sisal fabric(Faculty of Engineering, University of Kragujevac tribology@fink.rs Sestre Janjic 6 Kragujevac 34000, 2019) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.A study has been carried out to investigate the Mechanical and Tribological Properties of Woven Sisal Fabric. Two Plain fabrics were prepared by changing gram per unit area (GSM), and one weft rib fabric is prepared to understand the effect of woven structure on mechanical and wear properties. These fabrics textile properties were determined as per textile ASTM standards. The tensile properties of these fabrics were studied in both warp and weft directions. Further, pilling resistance, abrasion resistance and wear properties of these fabrics were studied using L27 Taguchi Orthogonal Array. The tensile properties were found to be better in weft direction as compared to warp direction in all type of fabrics. The pilling resistances were found better in weft rib fabrics. The abrasion resistance is exhibited better at higher GSM. From the results, it also reveals that higher the crimp value more the resistance against adhesion wear using Pin on disk method. More the yarn linear density more the resistance for adhesion wear. However, the wear load, woven pattern and traveling distance have a significant impact on weight loss and frictional force. © 2019 Published by Faculty of Engineering.Item Characterization and mechanical properties of sisal fabric reinforced polyvinyl alcohol green composites: Effect of composition and loading direction(Institute of Physics Publishing helen.craven@iop.org, 2019) Nagamadhu, M.; Jeyaraj, P.; Mohan Kumar, G.C.M.This research focuses on microstructure characterization and exploring mechanical properties of sisal fabric reinforced Polyvinyl Alcohol composites using conventional vacuum-assisted pressure compression method. Naturally available sisal fiber is used as reinforcement material in this composite because of its abundant availability in Southern India. The sisal fiber, PVA and its composites were characterized using Fourier Transform Infrared Spectroscopy. Initially, Polyvinyl Alcohol polymer was cross-linked with Glutaraldehyde, and mechanical properties were evaluated. It was observed that 20% Glutaraldehyde and 80% Polyvinyl Alcohol polymer combination yielded best mechanical properties. Further, two plain and one weft rib were considered and their textile properties were characterized. The results revealed that fabric crimp and yarn linear density had significant influence on tensile properties of the fabric. Influence of different fabric properties such as weaving pattern, grams per unit area, and loading direction on mechanical properties of composites were analyzed. The woven fabric having least gram per unit area of sisal resulted in best mechanical properties like tensile, bending, and impact. The weft rib fabric composites in weft direction exhibited best mechanical properties. © 2019 IOP Publishing Ltd.