Faculty Publications
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Item 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.Item Experimentation on dynamic compressive response of bio-inspired helicoidal structured Basalt/Hemp/polyurethane rubber sandwich composites(Elsevier Ltd, 2024) Gowda, D.; Mahesh, V.; Mahesh, V.; Ravishankar, K.S.In this article, to incorporate sustainability, enhance recyclability and achieve a good trade-off between the cost-weight-energy absorption performance, bioinspired helicoidal structured Basalt (B)/Hemp (H)/Polyurethane (PU) rubber hybrid composites are proposed, and their dynamic compressive response is experimentally investigated using a split Hopkinson pressure bar (SHPB) setup. These composites' high strain rate performance subjected to both in-plane and through-plane directions are studied. The strain rates ranging from 4254 to 10,750 s-1 are achieved by varying the striker bar's input pressure. In addition, the performance of the bioinspired helicoidal design is compared against the uniform monolithic and hybridised fibers laminated structures. The experimental results suggest that the dynamic compressive properties of Basalt/Hemp-helicoidal (BH-helicoidal) laminates were on compar with that of B-laminates, achieving an almost 30% weight reduction. The optimised fiber orientation at a helical angle of 120 enhances interlaminar shear strength, mitigating buckling and delamination failures, thereby improving BH-helicoidal laminate's structural integrity and dynamic compressive properties. Further, the through-plane dynamically loaded samples displayed better compressive properties due to increased stiffness than in-plane samples. The PU rubber matrix was thermally softened at higher strain rates, enhancing the flow stress. The strengthening mechanism of the proposed composites was evaluated through Cowper-Symonds, strain rate sensitivity, and thermal activation volume parameter. Macroscopic and microscopic imaging was proposed to understand the damage behaviour of laminates as a function of loading direction. Overall, BH-helicoidal laminate is favoured for ballistic application due to its cost-effectiveness and sustainable design. © 2024 Elsevier LtdItem Tribological performance and 3-D surface characterisation of age-hardened Al2090-based ceramic composites(SAGE Publications Ltd, 2025) Sharath, B.N.; Mahesh, V.; Mahesh, V.; Kattimani, S.; Harursampath, D.This study investigates the synergistic influence of boron nitride (BN) tertiary ceramic additives and age-hardening treatment on the microhardness and wear resistance of Al2090-based hybrid composites, fabricated using the stir casting method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) studies are carried out to assess the phases present, microstructure, and surface properties, respectively. The metallurgical investigations confirm a relatively superior uniformity in the distribution of particles and the ageing of precipitation at 150°C, vis-à-vis the other temperatures explored in this study. The experimental examinations conducted as per ASTM (E8 and G99) standards revealed a significant improvement in both the hardness and the primary tribological properties, when micron-sized boron carbide, graphite, and boron nitride were used as reinforcements. Age-hardened samples, especially the hybrid composite HS-2 with 5 wt.% each of boron carbide, graphite, and boron nitride, demonstrated an enhanced hardness of 25.23% and lower surface roughness (44.3 nm) compared to Al2090 (AS), due to the presence of load-bearing ceramic reinforcements. Increasing the applied load led to higher wear rates and coefficients of friction for Al2090. However, heat-treated hybrid metal matrix composites (HMMCs) exhibited a contrary behaviour, suggesting enhanced durability. The investigation highlighted the better wear resistance of heat-treated and near-optimally reinforced HMMCs, indicating their potential candidature for wear-resistant aerospace applications. © IMechE 2025.Item On enhancing the high-temperature wear behaviour of Al2090-based hybrid composites using tertiary ceramic particles(SAGE Publications Ltd, 2025) Sharath, B.N.; Mahesh, V.; Mahesh, V.; Kattimani, S.; Harursampath, D.This study explores the impact of reinforcing an Al2090 matrix with silicon nitride (Si3N4) as a tertiary ceramic alongside boron carbide (B4C) and graphite (Gr) to improve wear resistance at elevated temperatures. Hybrid composite samples were produced using the stir-casting technique. Experimental results show that incorporating Si3N4increased hardness by 35.7%, while wear resistance improved by 43.7% with a combined reinforcement of B4C, Gr, and Si3N4at 18 wt.%. Scanning electron microscopy (SEM) revealed the formation of a mechanically mixed layer (MML) composed of B4C, Gr, and Si3N4, which acted as an effective insulating barrier, protecting the sample surface from the steel disc. A noteworthy 69% of wear resistance improvement was accomplished at 300 °C for the composite with 9 wt.% B4C, 6 wt.% Gr, and 3 wt.% Si3N4. Atomic force microscopy (AFM) analysis further indicated enhanced surface properties for this composition. These findings highlight the potential of this hybrid composite for high-temperature aerospace applications, such as in engines, heat shields, and structural components. © IMechE 2024