Faculty Publications

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Author: search.filters.author.Ravishankar, K.S.Subject: search.filters.subject.Energy absorption

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Now showing 1 - 6 of 6
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    Ballistic Impact Study on Jute-Epoxy and Natural Rubber Sandwich Composites
    (Elsevier Ltd, 2018) Sangamesh, R.; Ravishankar, K.S.; Kulkarni, S.M.
    Since ages, human beings have used different methods to protect themselves and their armors from the impact of bullets/projectiles by using structures made up of wood, metals, glass and sand bags etc. These protective structures are heavy and incur cost and inconvenience to transport. Of late, they are replaced by structures of polymers and their composites, because of their light weight and good corrosion resistance. Ballistic impact analysis of composite materials is necessary in order to establish their use in military, aerospace and automotive applications either through experimental studies or using modeling techniques. The aim of the present investigation is to model and analyze the behavior of composites for ballistic impact. Residual velocity, energy absorption and ballistic limit for three different materials Jute-Epoxy (JE), Rubber (Ru), Jute-Epoxy-Rubber sandwich (JRE) for three thicknesses (5, 10, 15mm) and at three velocities (150, 250, 350 m/s) is studied. The study exhibits a significant amount of energy absorption in rubber, almost 10 times as compared to JE plate. Also damage observed was ductile in the case of rubber, while brittle in JE. Sandwich composites (JRE) displayed energy absorption and ballistic limit on par with rubber plates. Thus the applicability of these sandwiches in ballistic impact is established as better energy absorbing protective target structures. © 2017 Elsevier Ltd.
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    Study on ballistic energy absorption capability of glass-epoxy and jute-epoxy-rubber sandwich composites
    (Trans Tech Publications Ltd ttp@transtec.ch, 2018) Rajole, S.; Ravishankar, K.S.; Kulkarni, S.M.
    High velocity impact analysis of natural fiber reinforced composites is essential as the trend is focused towards the development of light weight, environment-friendly, non-corrosive and economical materials. At present, the defence, aerospace and automobile sectors are using synthetic fiber composites which are expensive and non-eco-friendly. In the present study ballistic impact of jute-epoxy (JEC), glass-epoxy (GEC), jute-epoxy-rubber (JERC) sandwich composites are simulated with different thickness (1, 2 and 3 mm) and velocity variations (100, 200 and 300m/s) using Finite Element analysis software. Although different approaches to the analysis of the effect response of composite structures are available, numerical modeling is based on strict constitutive models is often preferred because it can provide valuable detailed information about the spatial and temporal distribution of damage during the impact. The ballistic parameters such as energy absorption, ballistic limit and fracture behaviors are predicted. The composite is made of 8 noded linear brick elements and the bullet/projectile is modeled as a discrete rigid element in which deformation behavior, energy absorption and penetration behaviors obtained are clearly represented. The simulation results predicted match well with the analytical results obtained. Among all the combination of the materials simulated, the sandwiches have better ballistic qualities. Energy absorption of sandwich(JERC) was found 67 percentage higher than GEC and 56 percentage higher than JEC laminate. In future, these materials can be the alternative materials for defence sector for bullet proofing. © 2018 Trans Tech Publications, Switzerland.
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    Ballistic performance study of kevlar29 fibre reinforced polyester composite
    (Trans Tech Publications Ltd ttp@transtec.ch, 2019) Sangamesh, R.; Hiremath, H.; Ravishankar, K.S.; Kulkarni, S.M.
    Ballistic qualities of the material are important for the military defence barrier application for protection of military persons, their vehicles and equipment. In the present investigation ballistic performance of Kevlar29 fibre reinforced polyester composite (KPC) is analysed. A definite parametric study, taking into account various shape of projectiles (Flat-F, Spherical-S and Conical-C) impact on the composite target of different thicknesses (12, 16 and 20 mm). Impact velocity of the projectile considered for analysis 100-400 m / s. Ballistic parameters such as residual velocity, deformation and penetration behaviour are predicted. Conical projectile has more effect on the composite target compared to other projectile. Composite thickness influenced the energy absorption. The thickness increase from 12 mm to 20 mm which leads to increase in the energy absorption by almost 20%. © 2019 Trans Tech Publications, Switzerland.
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    Study on ballistic characteristics of glass-epoxy-rubber sandwiches
    (Trans Tech Publications Ltd ttp@transtec.ch, 2020) Sangamesh, R.; Hiremath, H.; Ravishankar, K.S.; Kulkarni, S.M.
    This article focuses on the Finite Element (FE) analysis of the ballistic performance of the polymer composites. These composites consisting of natural rubber (NR), glass-epoxy (GE) and glass-rubber-epoxy (GRE) sandwich of different thicknesses (3, 6 and 9 mm) under the impact of the conical nose projectile for a velocity variation of (180, 220 and 260 m / s). FE modeling was carried out to forecast the energy absorption, ballistic limit velocity and failure damage mode of the target material. The significant influence of thickness, interlayers and sandwiching effect was studied: the lowest ballistic limit was obtained for 3 mm thick GE. The energy absorption capacity of GRE sandwich was highest among the natural rubber and GE. The work can be extended for the experimental validation purpose so that these polymer composite materials could be utilized in the defense sector for bullet-proofing. © 2020 Trans Tech Publications Ltd, Switzerland.
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    Performance study of jute-epoxy composites/sandwiches under normal ballistic impact
    (China Ordnance Society, 2020) 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 Authors
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    Low-velocity impact characterization of polyurethane rubber/nano-clay enriched sustainable sandwich composites: Synergy of experimentation and simulations
    (John Wiley and Sons Inc, 2024) Gowda, D.; Mahesh, V.; Mahesh, V.; Ravishankar, K.S.
    This research proposes a novel sustainable composite using basalt (B), hemp (H) and polyurethane rubber (Pu) reinforced in nano clay functionalised epoxy matrix for sacrificial structural applications prone to low-velocity impact (LVI). To this end, symmetric and asymmetric laminates such as HHHH, BBBB, BHHB, BHPuHB, BBPuHH and BPuBPuHPuH are fabricated using compression molding techniques and subjected to LVI at three different impact energies of 19.66, 39.39, and 59.05 J. The hemp fibers were treated with NaOH solution before fabrication. Material characterization such as X-ray diffraction, Raman spectroscopy and morphological studies has been carried out. The impact and post-impact properties of the proposed composites are experimentally evaluated and validated with the finite element (FE) results. The effect on the residual tensile strength degradation of laminates at different interlayers and energy levels is also investigated using the Caprino analytical model. The barely visible impact damages (BVID) are investigated through non-destructive dye-penetration tests, which facilitate easy identification of the prominent LVI damages like “Plateau” and “Cliff-drop” impressions. Based on the impact energy absorption and residual tensile strength, proposed laminates followed BHPuHB > BBBB > BHHB > HHHH. The experimentation suggests that Polyurethane core laminates support maximum impact energy absorption by favoring a structural change in interlayers. Also, the residual tensile strength decreases as impact velocity increases. Highlights: Low-velocity impact behavior of sustainable composites is experimented. Basalt, hemp and polyurethane rubber are reinforced in nano clay epoxy matrix. A FE framework to validate the experimentation is proposed. Dye penetrant NDT is adopted to investigate the damages. Morphological studies are conducted to understand LVI responses. © 2024 Society of Plastics Engineers.