Faculty Publications

Now showing 1 - 4 of 4

Optimization of process parameters for ballistic impact response of hybrid sandwich composites
(Springer-Verlag Italia s.r.l., 2023) Mohan Kumar, T.S.; Joladarashi, S.; Kulkarni, S.M.; Doddamani, S.
The low-cost, eco-friendly ballistic impact resistance materials are gaining more importance in defense applications. The present work investigates the findings of ballistic impact behavior of a Jute-Rubber-Jute-Epoxy (Sand)-Jute-Rubber-Jute (JRJ-ES-JRJ) hybrid sandwich composite for different core thicknesses (10, 15, 20 mm) and different filler composition (0, 20, 40%) subjected to impact at 350 mps using different shaped projectiles like flat (F), conical (C), and hemispherical (H) using a numerical and parametric approach. Hybrid JRJE(%S)JRJ sandwich composites is modeled and simulated using commercially available dynamic explicit software, with the projectile as a rigid body and the target as a deformable material. Simulations are performed as per Taguchi's design of experiments approach for the L27 orthogonal array. The results show that filler composition and core thickness are the most critical factors determining ballistic behavior for the proposed hybrid sandwich composite structure. The Hybrid JRJ-ES-JRJ sandwich composites impacted with a conical-shaped projectile absorb the maximum energy, but the composite impacted with a flat-shaped projectile suffers more severe and immediate damage. © 2022, The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.
Comparative study on low velocity impact behavior of natural hybrid and non hybrid flexible thermoplastic based composites
(SAGE Publications Ltd, 2023) Kumbhare, K.; Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
The current study attempts to evaluate the low-velocity impact (LVI) behavior of jute and banana fiber-based hybrid and non hybrid green composites. The proposed composites are fabricated using compression moulding method with variety of positioning of layers namely jute-rubber-jute-rubber-jute (JRJRJ), banana-rubber-banana-rubber-banana (BRBRB), jute-rubber-banana-rubber-jute (JRBRJ) and banana-rubber-jute-rubber-banana (BRJRB). Thus developed composites are subjected to LVI testing using conical and hemispherical shaped impactor in drop weight impact testing machine and different impact velocities of 5 m/s, 10 m/s and 15 m/s. Based on the ability of the proposed composites to absorb energy, coefficient of restitution (CoR), energy loss percentage (ELP), and failure behaviour, the suggested flexible composites’ performances are assessed. The study reveals that JRJRJ composite exhibits better energy absorption capability and BRBRB exhibits least energy absorption capability compared to its counterparts. The damage study reveals that hemispherical impactor leads to more damage area due to its larger contact area whereas, conical impactor results in local penetration. Results reveals that inclusion of jute fiber as reinforcement results in better LVI properties compared to banana fiber. It is also clear that the presence of a compliant matrix improves energy absorption and damage resistance in flexible composites. © The Author(s) 2022.
Experimental and numerical investigation on the elastic properties of luffa–cenosphere-reinforced epoxy hybrid composite
(John Wiley and Sons Inc, 2024) Gurjar, A.K.; Kulkarni, S.M.; Joladarashi, S.; Doddamani, S.
Estimating the elastic characteristics of natural fiber-reinforced polymer composites such as luffa fiber reinforced with epoxy is challenging. The structure of luffa cylindrica is complex, like a three-dimensional natural fibrous mat, netting-like structure. The multiscale modeling of such structures is the challenge to be addressed. The prime objective of this work is to determine the specific elastic properties of luffa–cenosphere-reinforced epoxy (LCE) composite, considering the effect of filler volume fractions. Furthermore, multiscale modeling techniques, such as representative volume elements (RVEs) of finite element techniques with chopped, unidirectional, plain, and twill weaving fiber arrangements, were employed. The longitudinal modulus, transverse modulus, shear modulus, and Poisson's ratio were predicted through these modeling approaches. However, experimental and analytical methodologies, including the rule of mixture and Halpin–Tsai, were considered to validate the finite element analysis results. The elastic characteristics of LCE composite were therefore shown to be enhanced by increasing filler volume fraction. However, the cenosphere's 20% volume fraction has the highest elastic properties as determined by analytical, experimental, and computational models. Analytical and finite element simulation results were compared with the experimental results, and based on the findings, the most suitable (unidirectional, chopped, plain, and twill weaving) RVE was identified for finite element modeling of LCE composite for the evaluation of elastic properties. Results from practical approaches and the RVE twill weaving model showed good agreement, with less than 1% error, compared to the other analytical and finite element methods. Highlights: NFCs are gaining ground in polymer composites. Overcoming challenges in modeling of luffa fiber inside epoxy matrix. The study uses multiscale modeling with diverse fiber arrangements. Experimental and analytical methods used to confirm FEA results. Increased cenosphere volume fraction boosts LCE composite properties. © 2024 Society of Plastics Engineers.
Mode-I fracture behaviour of aramid/glass-epoxy interply hybrid composites
(SAGE Publications Ltd, 2025) Kanakannavar, S.; Biradar, S.; Hiremath, S.; Rajole, S.; Pitchaimani, J.; Kulkarni, S.M.; Goh, K.-L.
This article presents the influence of hybridisation of aramid and glass fibre woven fabric on fracture toughness (KIC) of the composites. Experiments using single-edge-notched-bending (SENB) were conducted to investigate the hybridisation effect on the Mode I fracture toughness specimen of aramid/glass laminates. The results revealed that the aramid epoxy composites yielded the highest KIC, followed by aramid/glass epoxy hybrid composites, and finally, glass epoxy composites, which exhibited the lowest KIC. Fracture micrographs of the hybrid composites showed similar fracture patterns – fibre pullout, fibre rupture and matrix rupture – to those of the aramid and glass epoxy composites. The mechanical properties of the hybrid composites being inferior to those of the aramid epoxy composites suggest that there is no advantage in using glass fibres to partially replace aramid fibres in achieving hybrid composites. © The Author(s) 2025

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