Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Joladarashi, S.Subject: search.filters.subject.Design of experiments

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    Experimental investigation on slurry erosive behaviour of biodegradable flexible composite and optimization of parameters using Taguchi's approach
    (Lavoisier, 2018) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    In the present study, the emphasis is on analysing the slurry erosive behaviour of novel green flexible composite made from jute fiber and natural rubber of ribbed smoke sheet (RSS) grade. The bonding gum made of natural rubber is used to bind the fiber and RSS rubber. Three different stacking sequences namely jute-rubber-jute (JRJ), jute-rubber-rubberjute (JRRJ) and jute-rubber-jute-rubber-jute (JRJRJ) are considered. Erosive studies are carried out on the prepared composites under three different rotation speeds (500, 1000 and 1500 rpm) and three different sand concentration (50, 75 and 100 gms) with silica sand as the abrasive medium dispersed in tap water. Design of experiments (DOE) is carried out using Taguchi's L9 orthogonal array on slurry erosion test to find out the effect of the stacking sequence, rotation speed and sand concentration on the weight loss of the composite. Through ANOVA, it was concluded that sand concentration is the main factor affecting the weight loss of composite. Regression model is developed and it was found that the developed model is adequate and feasible to predict the weight loss due to slurry erosion within the range of experimental conditions. © 2018 Lavoisier. All rights reserved.
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    Influence of thickness and projectile shape on penetration resistance of the compliant composite
    (China Ordnance Industry Corporation, 2021) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    The present study deals with development of conceptual proof for jute rubber based flexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element (FE) method. The proposed flexible composite blocks of repeating jute/rubber/jute (JRJ) units are modelled with varying thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat (F), ogival (O) and hemispherical (HS) shaped projectiles. All the considered projectiles are impacted with proposed flexible composite blocks of different thicknesses and the penetration behaviour of the projectile in each case is studied. The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of thickness and projectile shape on percentage of penetration depth is statistically analyzed using Taguchi's design of experiments (DOE). Results reveal that the though proposed flexible composite block with thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile, considering the safety issues, it is recommended to use the flexible composite with thickness of 120 mm. The nature of damage caused by the projectile in the flexible composite is also studied. Statistical studies show that thickness of the block plays a prominent role in determining the damage resistance of the flexible composite. © 2020 The Authors
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    Numerical approach for optimization of magnetic roller and evaluating the performance of permanent magnet roller separator through design of experiment
    (Elsevier B.V., 2022) Mohanraj, G.T.; Joladarashi, S.; Hanumanthappa, H.; Shanmugam, B.K.; Vardhan, H.; Naik, G.M.; Bhat Panemangalore, B.P.; Rahman, M.R.
    The present study is focused on numerical analysis of magnetic roller (Mr) using finite element method magnetics (FEMM) software for different magnet disc-to-steel disc (MD-to-SD) width ratios. The numerical (FEMM) results reveal that, the optimized Mr with the MD-to-SD width ratio of 5 mm: 2.5 mm was proved advantageous because of the effective magnetic field (Mf) value of 0.89–2.59 T. The artificial neural network (ANN) modelling technique was used for the prediction analysis of obtained numerical results. Furthermore, by using optimized Mr, the lab-scale permanent magnet roller separator (PMRS) was developed and parametric optimization has been carried out using Taguchi-based L27 orthogonal array design. The significance of parameters on the overall quality of the product has also been evaluated quantitatively by the analysis of variance (ANOVA) method. It was found that the belt thickness was the most influential factor in the product of desired Fe grade and recovery %. The obtained regression coefficient (i.e., R2 = 87.13 and 91.69% for Fe grade and Fe recovery %, respectively) and normal probability plot show the highest correlation between the experimented and predicted data. The results suggested that the numerical approach was suitable for designing optimized Mr for the processing of paramagnetic minerals. © 2022 Faculty of Engineering, Alexandria University
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    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.
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    Investigation of mechanical properties of luffa fibre reinforced natural rubber composites: Implications of process parameters
    (Elsevier Editora Ltda, 2024) Gurjar, A.K.; Kulkarni, S.M.; Joladarashi, S.; Doddamani, S.
    Natural fiber-reinforced composite materials are highly beneficial due to their excellent strength-to-weight ratio, and the compression molding process is frequently used to prepare natural fiber composites. The primary objective of the present work is to optimize the process parameters of the compression molding method to prepare luffa fiber-reinforced natural rubber composite and investigate the influence of process parameters on mechanical properties. Pre-processing parameters, specifically oven-dry temperature and time, processing parameters such as soaking temperature, time, and compression pressure, and post-processing parameters, such as oven-dry temperature and time, were considered to optimize. Natural rubber in its latex phase is utilized as a matrix material, and luffa fiber is used as reinforcement. The Plackett-Burman screening design technique was employed to identify the impact of different processing parameters on the mechanical properties of the luffa fiber-reinforced natural rubber (LNR) composite, and based on Taguchi's design of experiments, several process parameters were utilized to create L27 orthogonal array and the mentioned composites prepared accordingly. The ASTM standard is followed while testing the composite samples to determine their density, shore A hardness, and tensile strength. The density of the composite is unaffected by the process parameters; however, the shore A hardness of the composite is significantly affected. All the processing parameters most significantly impacted the tensile strength of LNR composites. The optimized process parameters for preparing LNR composite are the pre-oven temperature of 65 °C and time of 150min, the soaking temperature of 75 °C and time of 5min, compression pressure of 1.5 MPa, and the post-oven dry temperature of 55 °C and time of 45min. LNR composite can absorb energy due to its rubber matrix, making it useful for high-impact applications. © 2024 The Authors
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    Experimental and Numerical Investigation of the Performance of Luffa Fiber-Reinforced Natural Rubber Composites with Process Parameter Optimization using DOE
    (Korean Fiber Society, 2025) Gurjar, A.K.; Kulkarni, S.M.; Joladarashi, S.; Doddamani, S.
    Composite materials have gained significant attention due to their high strength-to-weight ratio and sustainability. In particular, natural fiber-reinforced composites are increasingly investigated as environmentally friendly alternatives to synthetic counterparts. This study focuses on fabricating lightweight and biodegradable luffa fiber-reinforced natural rubber (LNR) composites using compression molding, emphasizing optimizing key processing parameters—temperature, curing time, and compression pressure. Latex-form natural rubber was selected as the matrix owing to its biodegradability, low cost, and compatibility with natural fibers. In contrast, luffa fiber served as reinforcement due to its favorable mechanical properties. The Design of Experiments (DOE) approach, specifically Taguchi’s method, was employed to systematically analyze the influence of processing parameters on physical and mechanical performance. Experimental evaluation of mechanical properties was conducted according to ASTM standards. The rule of mixture was used to evaluate the mechanical properties analytically. The multiscale material modeling finite element (FEM) methods were used to assess the orthotropic properties using the representative volume element technique. Results showed that density was only marginally affected by processing conditions, with ROM and FEM generally overestimating values; however, FEM provided closer agreement to experimental data. Shore A hardness and longitudinal modulus highly depended on curing temperature and time, with optimal properties obtained at 100 °C for 15 min under 1.0 MPa pressure. Similarly, the maximum ultimate tensile strength (0.40 MPa) was achieved under the same conditions, attributed to enhanced fiber–matrix bonding and crosslinking. Statistical analysis (ANOVA) confirmed temperature as the most influential parameter, followed by pressure and curing time. Optimized processing conditions significantly improved fiber–matrix adhesion, resulting in superior mechanical performance. These findings provide reliable processing guidelines for developing high-performance, environmentally sustainable LNR composites, making them suitable for high-impact applications in defense and consumer sectors. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.