Faculty Publications
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Item 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.Item 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.Item Effect of clamshell powder on the mechanical and damping properties of epoxy-bamboo composites(SAGE Publications Ltd, 2024) Anand, K.J.; Ekbote, T.; Doddamani, S.; Ashoka, E.Compared to single natural fibre composites, hybridising natural fibres with filler particles presents a promising avenue for enhancing composites physical, mechanical, and damping properties. This study delves into incorporating clamshell powder, a filler derived from clams’ hard protective outer shells, into polymer composites. The focus is on investigating the potential of clamshell powder as a filler material to augment the mechanical and damping properties of epoxy-bamboo mat composites. The weight ratio of clamshell fillers varied from 0% to 9%, and the compression moulding method was used to fabricate the composites. As per ASTM standards, mechanical properties were evaluated by conducting tensile and flexural tests. Free vibration tests by impact hammer technique were employed to evaluate the natural frequency, damping ratio, and mode shapes of developed composites to measure damping properties. Results revealed that adding clamshell filler significantly improved composites tensile strength, flexural strength, and damping properties. The addition of clamshell elevated the tensile strength by 18.5%, and flexural strength by 24.2% for composite with 6 wt% filler, which can be attributed to the efficiency of load transfer and the interfacial bonding between fillers and epoxy matrix. SEM analysis supported the experimental results obtained. The highest damping value is received for 9 wt% filler, showing 30% enhancement compared to composites without clamshell filler. Modal analyses using ANSYS software further validated the positive impact of clamshell filler. This study underscores the potential of clamshell filler in enhancing the mechanical and damping properties of epoxy-bamboo composites, broadening their applicability in various fields. © IMechE 2024.Item Seashell-based filler as sustainable reinforcement: a novel approach to enhance wear performance of bamboo-epoxy composites(Institute of Physics, 2025) Anand, K.J.; Murthy, A.G.S.; Ekbote, T.; Doddamani, S.; Madhusudhana, H.K.; Patil, A.S.Seashell wastes are discarded in landfills, causing environmental problem. This study presents a novel approach to valorize seashell waste by converting them into filler particulates and incorporate it into bamboo–epoxy composites. Composites of varying clamshell filler (0–9 wt%) loading were prepared using compression molding method. The wear behavior of composites was studied under dry sliding conditions on a pin-on-disc tribometer following ASTM G99 standard. Taguchi-ANOVA method was employed for statistical analysis of results and to identify the significant factors affecting wear rate. The results showed that adding seashell particles improved the hardness and wear resistance of the bamboo composites. ANOVA results indicated that load has the maximum effect of 47.4% and speed has the effect of 29.4%. Optimal performance was achieved for 6 wt% filler addition, exhibiting 17% improvement in hardness and wear rate was reduced by 60%. The enhancement in wear resistance of bamboo composite was correlated with an increase in hardness and a decrease in damage to the impact surface, as observed in SEM micrographs. These findings establish clamshell filler as an effective reinforcement for improving wear performance of bamboo composites. © 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.