Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Joladarashi, S.Subject: search.filters.subject.Rubber

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    Comparative study on energy absorbing behavior of stiff and flexible composites under low velocity impact
    (American Institute of Physics Inc. subs@aip.org, 2019) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    This paper deals with the comparative study on the energy absorbing behaviour of the flexible composites with that of stiff composites aiming at automobile cladding application. Two types of composites namely Jute-Epoxy (JE) laminate and Jute-Rubber-Jute (JRJ) sandwich are chosen for the purpose of study under impact velocity varying from 2.5 m/s to 10 m/s. The study is carried out using commercially available finite element simulation software. The energy absorption and damage behavior of both the composites are studied. From the results, it was found that JRJ sandwich absorbs almost 54%, 51.2%, 58.1% and 61.78% more energy compared to JE laminate for impact velocity of 2.5 m/s, 5 m/s, 7.5 m/s and 10 m/s respectively and exhibits compliant nature as opposed to JE laminate which exhibits brittle nature. The energy absorption ratio of JRJ sandwich is more compared to JE laminate. Thus, the JRJ sandwich composites are expected to provide better energy absorption, reduce damage propagation under low velocity impact, thereby making them a potential material for automobile structural protective claddings. © 2018 Author(s).
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    Comparative study on kevlar/carbon epoxy face sheets with rubber core sandwich composite for low velocity impact response: FE approach
    (Elsevier Ltd, 2021) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    Recent trend has shifted towards replacing the conventional materials by fiber reinforced polymer composites for various structural applications since the fiber reinforced polymer composites exhibit high strength, lighter weight and low cost. This paper work concentrates on analysing the low velocity impact response of two types of sandwich composites namely kevlar epoxy with rubber core (KE-R-KE) and carbon epoxy with rubber core (CE-R-CE) in terms of energy absorption and damage mitigation. Modelling and analysis is carried out by making use of commercially available explicit finite element (FE) software. Results reveal that kevlar based sandwich composite outstands the carbon based composite both in terms of energy absorption by 37.7% and the energy absorption ratio of KE-R-KE is 1.36 times more compared to CE-R-CE sandwich composite. The damage study reveals that both the proposed sandwich composites exhibit similar damage mechanism dominated by matrix cracking followed by fiber breakage and delamination. The presence of rubber as core material helps in mitigating the damage to the bottom facesheet. © 2021 Elsevier Ltd. All rights reserved.
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    Experimental investigation on slurry erosive behaviour of biodegradable flexible composite and optimization of parameters using Taguchi's approach
    (Lavoisier, 2018) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    In the present study, the emphasis is on analysing the slurry erosive behaviour of novel green flexible composite made from jute fiber and natural rubber of ribbed smoke sheet (RSS) grade. The bonding gum made of natural rubber is used to bind the fiber and RSS rubber. Three different stacking sequences namely jute-rubber-jute (JRJ), jute-rubber-rubberjute (JRRJ) and jute-rubber-jute-rubber-jute (JRJRJ) are considered. Erosive studies are carried out on the prepared composites under three different rotation speeds (500, 1000 and 1500 rpm) and three different sand concentration (50, 75 and 100 gms) with silica sand as the abrasive medium dispersed in tap water. Design of experiments (DOE) is carried out using Taguchi's L9 orthogonal array on slurry erosion test to find out the effect of the stacking sequence, rotation speed and sand concentration on the weight loss of the composite. Through ANOVA, it was concluded that sand concentration is the main factor affecting the weight loss of composite. Regression model is developed and it was found that the developed model is adequate and feasible to predict the weight loss due to slurry erosion within the range of experimental conditions. © 2018 Lavoisier. All rights reserved.
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    Investigation on the eect of using rubber as core material in sandwich composite plate subjected to low-velocity normal and oblique impact loadings
    (Sharif University of Technology, 2019) Mahesh, V.; Joladarashi, S.; 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.
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    Physio-mechanical and wear properties of novel jute reinforced natural rubber based flexible composite
    (Institute of Physics Publishing helen.craven@iop.org, 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.
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    Comparative study of damage behavior of synthetic and natural ber-reinforced brittle composite and natural ber-reinforced exible composite subjected to low-velocity impact
    (Sharif University of Technology, 2020) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    In the present study, a comparative study of the damage behavior of Glass-Epoxy (GE), Jute-Epoxy (JE) laminates with [0=90]s orientation, and Jute-Rubber-Jute (JRJ) sandwich is carried out by ABAQUS/CAE nite element software. The GE, JE laminate, and JRJ sandwich with a thickness rate of 2 mm are impacted by a hemispherical-shaped impactor at a velocity of 2.5 m/s. The mechanisms by which the brittle laminate gets damaged are analyzed in accordance with Hashin's 2D failure criterion, and exible composites are analyzed by the ductile damage mechanism. The absorbed energy and the incipient point of each laminate were compared. According to the results, there was no evidence of delamination in JRJ as opposed to GE and JE. The compliant nature of a rubber plays a role in absorbing more energy, which is slightly higher than the energy absorbed in GE. Moreover, it was observed that there was no incipient point in JRJ sandwich, meaning that there was no cracking of matrix since the rubber was elastic material. Thus, the JRJ material can be a better substitute for GE laminate in low-velocity applications. The procedure proposed for the analysis in the present study can serve as a benchmark method for modeling the impact behavior of composite structures in further investigations. © 2020 Sharif University of Technology. All rights reserved.
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    Evaluation of tensile strength and slurry erosive behaviour of jute reinforced natural rubber based flexible composite
    (International Information and Engineering Technology Association info@iieta.org, 2020) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    Polymer based natural fiber reinforced composites are finding their applications in almost all fields of engineering. Flexible composites are different class of composite materials finding their usage in secondary structural application such as sacrificial structures like claddings. Mechanical and tribological characterization of the newly developed composites becomes important prior to using them in any engineering application. The present study concentrates on evaluating the tensile and slurry erosive behaviour of flexible composite manufactured by reinforcing naturally available jute fiber in the form of woven fabric in the naturally available sun dried rubber sheets (NR) using compression moulding technique. ASTM D412 standard is used to evaluate the tensile properties of the proposed flexible composite and the NR sheets. The slurry erosive behaviour is assessed using Ducom slurry erosion testing machine. The results reveal that reinforcing jute with natural rubber enhances the tensile strength compared to natural rubber sheet and the wear of the proposed flexible composite is minimal due to inclusion of natural rubber which is elastic in nature. © 2020 Lavoisier. All rights reserved.
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    Tribo-mechanical characterization and optimization of green flexible composites
    (ICE Publishing, 2020) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    The use of natural fibers as a substitute for synthetic fibers as reinforcement in polymer-based composites is finding prominence nowadays. The present paper deals with the comparative study of biodegradable flexible composites fabricated using jute fabric and rubber with different configurations-namely, jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ) and jute/rubber/jute/rubber/jute (JRJRJ)-using their tribo-mechanical properties as the attributes and making use of a multi-attribute decision making (MADM) approach-namely, technique for order of preference by similarity to ideal solution (Topsis). The tensile strength, tear strength, interlaminar shear strength and specific wear rate of the proposed composites are chosen as the attributes for comparison using Topsis. The results show that JRJRJ is the best configuration among the considered configurations of flexible composites, providing the overall best tribo-mechanical properties, and the fractography study shows that the proposed flexible composites undergo failure mainly due to matrix tearing in the case of tensile and tear tests as opposed to matrix cracking in the case of stiff composites. Also, the wear study reveals that rubber exhibits better resistance to wear. This study shows the efficient application of the statistically based MADM tool Topsis for material selection. © 2020 ICE Publishing: All rights reserved.
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    Influence of thickness and projectile shape on penetration resistance of the compliant composite
    (China Ordnance Industry Corporation, 2021) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    The present study deals with development of conceptual proof for jute rubber based flexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element (FE) method. The proposed flexible composite blocks of repeating jute/rubber/jute (JRJ) units are modelled with varying thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat (F), ogival (O) and hemispherical (HS) shaped projectiles. All the considered projectiles are impacted with proposed flexible composite blocks of different thicknesses and the penetration behaviour of the projectile in each case is studied. The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of thickness and projectile shape on percentage of penetration depth is statistically analyzed using Taguchi's design of experiments (DOE). Results reveal that the though proposed flexible composite block with thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile, considering the safety issues, it is recommended to use the flexible composite with thickness of 120 mm. The nature of damage caused by the projectile in the flexible composite is also studied. Statistical studies show that thickness of the block plays a prominent role in determining the damage resistance of the flexible composite. © 2020 The Authors
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    Damage mechanics and energy absorption capabilities of natural fiber reinforced elastomeric based bio composite for sacrificial structural applications
    (China Ordnance Industry Corporation, 2021) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    The present study deals with the experimental, finite element (FE) and analytical assessment of low ballistic impact response of proposed flexible ‘green’ composite make use of naturally available jute and rubber as the constituents of the composite with stacking sequences namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ) and jute/rubber/jute/rubber/jute (JRJRJ). Ballistic impact tests were carried out by firing a conical projectile using a gas gun apparatus at lower range of ballistic impact regime. The ballistic impact response of the proposed flexible composites are assesses based on energy absorption and damage mechanism. Results revealed that inclusion of natural rubber aids in better energy absorption and mitigating the failure of the proposed composite. Among the three different stacking sequences of flexible composites considered, JRJRJ provides better ballistic performance compared to its counterparts. The damage study reveals that the main mechanism of failure involved in flexible composites is matrix tearing as opposed to matrix cracking in stiff composites indicating that the proposed flexible composites are free from catastrophic failure. Results obtained from experimental, FE and analytical approach pertaining to energy absorption and damage mechanism agree well with each other. The proposed flexible composites due to their exhibited energy absorption capabilities and damage mechanism are best suited as claddings for structural application subjected to impact with an aim of protecting the main structural component from being failed catastrophically. © 2020 The Authors