Faculty Publications
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Item 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).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 low-velocity impact response of sandwich structure with functionally graded core(John Wiley and Sons Inc, 2024) Mohan Kumar, T.S.; Joladarashi, S.; Kulkarni, S.M.; Doddamani, S.The present research investigates optimizing the impact resistance of functionally graded sandwich structures using experimental and numerical approaches. The low-velocity impact (LVI) responses of functionally graded sandwich composite (FGSC) with different configurations with skin material jute/rubber/jute (JRJ) and core material having epoxy and sea sand by volume fraction of sea sand at 0%, 10%, 20%, and 30%. Sandwich structures were impacted with LVI (5.89, 10.92, and 15.18 m/s), with the impactor dropped from heights of 0.5, 1, and 1.5 m with precompressed spring loads. FGSC samples are considered a deformable body, and the impactor is modeled as a rigid body using commercially accessible dynamic explicit software. The burn-out test and weight method were used to test the core's gradience; both methods' results substantially matched, and the variance in gradation could be observed. The proposed sandwich structure characteristics are examined by energy absorption, peak force, energy loss percentage, and coefficient of restitution. Results showed that SC30S provides greater energy absorption and superior damage resistance when tested on LVI. To evaluate the accuracy of experimental findings in predicting the indentation behavior of the sandwich structure, the finite element analysis was used to compare with the experimental results. According to the examination of these proposed FGSC overall performance, they could potentially be employed as sacrificial materials for LVI applications like claddings to shield major structural components. The systematic approach used in this work serves as a standard for choosing and using FGSC effectively for LVI applications. Highlights: Low-velocity impact behavior of sandwich structures was investigated. Combining flexible skin and epoxy core enhances energy absorption. Based on impact energy levels, impact damage areas were determined. Examined sandwich structure advantages in structural and aerospace uses. In terms of time and cost, the numerical analysis method would be useful. © 2023 Society of Plastics Engineers.Item Influence of sea sand reinforcement on the static and dynamic properties of functionally graded epoxy composites(Springer Science and Business Media Deutschland GmbH, 2024) Mohan Kumar, T.S.M.; Joladarashi, S.; Kulkarni, S.M.; Doddamani, S.This study aims to study the static and dynamic properties of the functionally graded epoxy composites with sea sand particles as reinforcement. In this study, functionally graded polymer composites (FGPC) were fabricated by dispersing sea sand throughout the epoxy, exhibiting a spatially varying composition profile within the material. Physio-mechanical properties and high strain rate compression responses were determined for the prepared FGPC by varying the composition of sea sand [0%, 10%, 20%, and 30% (by weight)]. The gradience analysis was performed using the burn-out test and weight method, and the results significantly matched, as well as the variation in gradation could be identified. The density and void content are increased with increased sea sand composition. Tensile and specific strength for neat epoxy shows a 2.41 times increase compared to 30% sea sand-filled epoxy. When loaded from the composite side of FGPC, flexural strength increased by 27.93%, hardness increased by 12.47%, and impact strength increased by 2.35 times for 30% sea sand-filled epoxy compared to neat epoxy. Under dynamic compression loading, FGPC was subjected to split-Hopkinson pressure bar experiments for neat and filled epoxy. These samples were deformed at strain rates in the 103 s?1 while subjected to pressures of 2, 3, and 4 bar. Stress–strain curves and the strain rate were computed using the raw data. High strain rates improve compressive strength, which increases exponentially as the strain rates increase. Scanning electron microscopy micrographs of the fractured specimen are employed to analyze the fracture characteristics. Graphical Abstract: (Figure presented.) © Iran Polymer and Petrochemical Institute 2024.