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Item Tribo-mechanical and physical characterization of filament wound glass/epoxy composites(2019) Biradar, S.; Joladarashi, S.; Kulkarni, S.M.The present research aims to investigate mechanical, physical and tribological properties of filament wound Glass Fibre Reinforced Polymer (GFRP) composite pressure vessel as per respective ASTM standards. Here test coupons prepared from GFRP vessel are subjected to tensile, compression, flexural and impact testing to investigate mechanical properties. The physical properties are studied from density, ignition loss and water absorption tests. The tribological study was carried out using abrasive slurry erosion tester. All tests carried out in this study are as per respective ASTM standard. The results obtained from various mechanical testings are satisfactory and also almost equal in strength with respect to metallic pressure vessels. Particularly from impact testing, the strength of sea water treated sample has considerably increased. Fractography study was conducted on failed samples to study various mode of failure in detail. The physical characterization has elaborated the behavior of filament wound GFRP material under moisture environment which has observed a maximum of 0.5% water absorption rate. As per ignition loss study which reveals about 95%-98% weight of ignition loss is recorded, which indicates perfect fibre to resin ratio and almost nil or least % of void content. The slurry erosion test results are within the expected range and maximum wear of 9.67% is recorded under extreme case. The overall study reveals that the presence of voids, non-uniform distribution of fibre and matrix have an impact on the outcomes of many mechanical properties. From the above study we can conclude that filament wound GFRP pressure vessel can be used in many applications since it is a non-hydrophobic, better wear resistant and several strength parameters have also improved or unaltered under rigorous testing conditions. � 2019 IOP Publishing Ltd.Item Performance study of jute-epoxy composites/sandwiches under normal ballistic impact(2019) Rajole, S.; Ravishankar, K.S.; Kulkarni, S.M.This study is undertaken to explore the use of natural fiber Jute-epoxy (JE), Jute-epoxy-rubber (JRE) sandwich composite for ballistic energy absorption. Energy absorbed and residual velocities for these composites are evaluated analytically and through Finite Element Analysis (FEA). FE analysis of JE plates is carried out for different thicknesses (3, 5, 10 and 15 mm). JE plates and JRE sandwiches having the same thickness (15 mm) are fabricated and tested to measure residual velocity and energy absorbed. The analytical results are found to agree well with the results of FE analysis with a maximum error of 9%. The study on JE composite plate reveals that thickness influences the energy absorption. Experimental and FE analysis study showed that JRE sandwiches have better energy absorption than JE plates. Energy absorption of a JRE sandwich is about 71% greater than JE plates. Damages obtained from FEA and testing are in good agreement. SEM analysis confirms composites failed by fiber rupture and fragmentation. 2019 The AuthorsItem Processing and investigation of mechanical characteristics on the polydimethylsiloxane/carbon black composites(2019) Shivashankar, H.; 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.Item Predictive analysis of peel up delamination in glass fibre reinforced polyester composite drilling(2019) Bhat, R.; Mohan, N.; Kulkarni, S.M.; Sharma, S.Composites are the engineering materials, comprising two constituents: reinforcing and the matrix or binder material. the composite machining, particularly, drilling is a complex process in comparison to the machining of traditionally employed engineering structural materials. Delamination is the most prevalent integrity issue in composite drilling. In the present work, the independent variables are categorized as continuous and categorical variables. Speed and feed are chosen as the continuous variables, whereas, the drill tool diameter and material thickness are considered as categorical variables. The peel up delamination is chosen as the response. The central composite design form of RSM is employed to develop the experimental design and develop the response regression model. The developed model is then validated using an additional set of small number of experiments and the degree of affirmation is determined. The standard error obtained analytically is 5.91%. The experimental mean standard error for the randomly conducted validating experiment obtained is 4.23%. The validation shows a high degree of agreement (99.75%) between the theoretical and analytical values. TJPRC Pvt. Ltd.Item Physio-mechanical and wear properties of novel jute reinforced natural rubber based flexible composite(2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.This paper deals with the design, fabrication, physio-mechanical and wear characterization of the composites prepared from naturally available jute fiber and rubber matrix materials. Jute and natural rubber are cost effective, abundant and environmental friendly materials which can be used as fiber and matrix respectively. The flexible composite with different stacking sequence are manufactured using compression moulding machine and void percentage, water absorption percentage, tensile properties, tear strength, impact strength and shore hardness of the prepared composites are found along with the wear. The void content and water absorption are found to increase with increased number of plies in the composite with fibers contributing more compared to rubber. Tensile, tear, specific wear rate and hardness are found to better with a composite having minimum number of plies, which is JRJ. Charpy impact test revealed that the variation in specific impact strength of the three configuration of composites are negligible and no failure of composites were absorbed owing to their flexibility indicating all the three composites have additional capability to absorb much higher energy and suitable as sacrificial components for structural applications subjected to low velocity impact. The fractography analysis of tensile and tear test shows that the flexible composites are free from matrix cracking, but matrix tearing plays a vital role in failure. The mechanism of wear involved in the proposed composites when different constituents of the composite are exposed to abrasive medium is studied through surface morphology. 2019 IOP Publishing Ltd.Item Investigation on the eect of using rubber as core material in sandwich composite plate subjected to low-velocity normal and oblique impact loadings(2019) Vishwas, M.; Joladarashi, Sh.; Kulkarni, S.M.In this article, the structural performance of composite plate under low-velocity impact is studied. Two forms of layup sequence, namely, Jute-Epoxy laminate (JE) and Jute-Epoxy-Rubber sandwich (JE-R-JE), were considered for evaluation. Special emphasis was on evaluating the inuence of normal and oblique loadings. Various dynamic parameters, such as energy, peak load, and deformation, were analysed in detail to study the eect of impact angle on both laminate and sandwich structures. Stress analysis of both laminate and sandwich structures was carried out to discuss the eect of introducing rubber as a core material. The results revealed that using rubber as a core material had a signicant eect on energy absorption. In addition, it was noticed that increasing the angle of impact would yield better performance of the composite plate. The results presented here may serve as benchmark for eective utilization of composite plates in low-velocity impact applications. 2019 Sharif University of Technology. All rights reserved.Item Influence of weave pattern and composite thickness on mechanical properties of bamboo/epoxy composites(2019) Kanaginahal, G.M.; Hebbar, H.S.; Kulkarni, S.M.The results of an attempt made for studying the influence of weave pattern and composite thickness of plain and twill weave bamboo fabric reinforced epoxy/phenalkamine composites on static mechanical properties are reported in this paper. Plain weave and Twill weave bamboo fabric of 125 gsm were used as reinforcements with medium viscous epoxy B-11 resin and highly viscous AI 1041 phenalkamine bio-based hardener. Thickness of composite achieved were 3.1, 4.3 and 5.4 mm with fiber weight fraction at 18% by hand layup method. The aim was to study the influence of weave pattern and thickness of composite on the tensile, flexural and impact properties. Fourier Transform Infra-Red results showed the presence of cellulose, polysaccharides, cardanol groups and hydrogen bonding of reinforcement and matrix. X-Ray Diffraction peaks displayed higher intensities for twill weave fabric. Tensile studies of fabrics showed 7% higher strength for twill weave compared to that of plain weave fabric in warp direction. Twill weave composites with 5.4 mm thickness showed an increase of 12% in tensile strength and 8% increase in stiffness compared to plain weave composite of same thickness. Twill weave composite with 5.4 mm thickness showed an increase of 22% in flexural strength and 28% in stiffness compared to plain weave composite of same thickness. Izod impact results displayed an increase of 16% in absorbed energy for 5.4 mm thickness twill weave composite when compared with plain weave composite of same thickness. Fractography of fractured specimens of tensile test displayed fiber pullouts for plain weave composites and fiber breakage for twill weave composites. Twill weave composites have shown better wettability than that of plain weave composites. 2019 IOP Publishing Ltd.Item Influences of dielectric and conductive fillers on dielectric and mechanical properties of solid silicone rubber composites(2019) Shankar, B.S.M.; Kulkarni, S.M.Dielectric elastomers are materials being used for electromechanical transduction applications. Their electromechanical response depends on permittivity, Young s modulus and electric breakdown strength. A factor that limits its application is high operating voltages that can be reduced through improvement in permittivity. One of the methods is by incorporating high permittivity fillers into polymer matrix to obtain dielectric dielectric composites (DDC).These composites show high permittivity at the cost of reduced flexibility. An alternative solution is development of composites by incorporating organic or inorganic conductive fillers into polymer matrix. These composites show high permittivity with high dielectric loss and low breakdown strength. To overcome both the above limitations both dielectric and conductive fillers are incorporated into dielectric polymer matrix to obtain conductor dielectric composites (CDC). In this study, high temperature vulcanized solid silicone rubber as matrix has been used to prepare DDC composites with barium titanate (BT) filler and CDC composites with both BT as dielectric and ketjenblack as conductive fillers, using Taguchi design of experiments. The effect of factors such as amount of fillers and curing agent, mixing time in roll mill and curing temperature on the dielectric and mechanical properties are reported. Lichtenecker model predicts the permittivity of the DDC composite more accurately. For the CDC composites permittivity increased by 390%, effective resistivity decreased by 80%, Young s modulus increased by 368% and Shore A hardness increased by 90% as compared to those of reference matrix. Important interaction effects are observed among both the fillers that are uniformly dispersed without any aggregation. 2019, Iran Polymer and Petrochemical Institute.Item Influence of conductive and dielectric fillers on the relaxation of solid silicone rubber composites(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.Item Experimental study on Abrasive wear behaviour of flexible green composite intended to be used as Protective Cladding for Structures(2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.In the present study, the influence of material and process parameters on the two body abrasive wear behavior of Jute-Rubber flexible composite is investigated using Taguchi s design of experiments (DOE). Three different stacking sequences of composite namely jute-rubber-jute (JRJ), jute-rubber-rubber-jute (JRRJ) and jute-rubber-jute-rubber-jute (JRJRJ) are considered and their wear behavior is evaluated using two body abrasion test with multi-pass condition for abrading distances of 0.4 m to 1.2 m in increments of 0.4 m and varied load of 9.81 N, 12.26 N and 14.71 N. Abrasive volume loss and specific wear rate as function of abrading distance are determined. The results from Taguchi s design of experiments show that for two body dry sliding wear situation, an abrading distance significantly affects the specific wear rate compared to load and composite configuration. However, volume loss is more and appreciable when jute fabric is exposed to abrasive medium rather than when the rubber is exposed. Surface morphology study is carried out using a scanning electron microscope to get an insight of wear mechanism of constituents of the flexible composite. Stretching of asperities results in wear of the rubber, whereas fiber breakage causes wear of the jute. Rubber being the dominating constituent of flexible composite results in providing better wear resistant properties and thus can act as a potential candidate for sacrificial structures to protect primary structures subjected to wear. International Journal of Modern Manufacturing Technologies.