Faculty Publications
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Item A comparison of the non-conforming and conforming sector finite element for free vibration of circular discs(Elsevier Ltd, 2020) Avvaru, H.T.; Joladarashi, S.; Kadoli, R.A twelve-term non-conforming and a sixteen-term conforming displacement polynomial are obtained from Pascal's triangle to deduce the shape functions for a sector element. Using the sector element circular disc is discretized. The number of degrees of freedom for the sector element at a given node is three and four. Kirchhoff's plate theory is the basis for strain energy and kinetic energy because of the transverse motion of the circular plate. Associated stiffness and mass matrices for the sector element are derived in closed form using MATHEMATICA. Using the Lagrange equation, the free vibration equation of motion for the circular disc is derived. A validation study is conducted, and non-dimensional frequencies from the finite element solution are compared with the analytical solutions reported in the literature. Subsequently, the natural frequencies of Al-Al2O3functionally graded circular disc with gradation in the thickness direction are evaluated for a variety of boundary conditions. © 2020 Elsevier Ltd. All rights reserved.Item Finite Element Formulation for Static and Time Dependent Transverse Deflection of Functionally Graded Sandwich Beams with Viscoelastic Core(Springer Science and Business Media Deutschland GmbH, 2023) Patil, R.; Joladarashi, S.; Kadoli, R.The present study describes the finite element (FE) formulation for static and time dependent deflection of functionally graded (FG) sandwich beams with viscoelastic core. The kinematics of the beam are derived as per Euler–Bernoulli beam model. Rule of mixture and power law index define the variation of properties of FG stiff layers and core is considered as isotropic. Standard Linear solid model is used to define time dependent shear modulus of viscoelastic material. Static deflection results are validated with available literature. Effect of parameters on static deflection are studied for various boundary conditions. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Hygrothermal coupling analysis of magneto-electroelastic beams using finite element methods(Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2018) Mahesh, M.; Kattimani, S.C.; Joladarashi, S.In this article, the finite element (FE) method has been used to assess the coupled static behavior of hygro-thermo-magneto-electroelastic (HTMEE) beam. Influence of externally applied hygrothermal loads on the direct (displacements, electric and magnetic potentials) and derived quantities (stresses, electric displacement and magnetic flux densities) of HTMEE beam have been studied in detail. The principle of total potential energy and the coupled constitutive equations of HTMEE material are used for the FE formulation. A generalized condensation technique is adopted to solve the global FE equations of motion. Numerical examples are discussed to examine the effect of hygrothermal loads and distinct effect of moisture concentration on the behavior of the beam. Particular emphasis has been placed to analyze the influence of temperature and moisture dependent elastic stiffness coe?cients associated with empirical constants. Considering the independent effect of temperature and moisture on the coupled static responses, the most significant combination of the empirical constants corresponding to temperature dependency and moisture dependency are explored. Extensive computational examples are considered to examine the significant effect of boundary conditions, temperature gradient, moisture concentration gradient and empirical constants on the static behavior of HTMEE beam. It is observed that the static behavior of HTMEE beam is significantly influenced by the hygrothermal loads and empirical constants. The results presented in this article would serve as a benchmark results in design and analysis of HTMEE structures for sensors and actuators applications. © 2018 Taylor & Francis.Item Design and fabrication of optimized magnetic roller for permanent roll magnetic separator (PRMS): Finite element method magnetics (FEMM) approach(Elsevier B.V., 2021) Mohanraj, G.T.; Rahman, M.R.; Joladarashi, S.; Hanumanthappa, H.; Shanmugam, B.K.; Vardhan, H.; Rabbani, S.A.In the present work, an attempt has been made to develop a PRMS in a cost effective and environmental friendly way through FEMM analysis of magnetic roller (active part of PRMS). The FEMM analysis indicates that, the optimized magnetic roller having magnet-to-steel disk thickness ratio of 5 mm: 2.5 mm was proved to be gainful in beneficiating paramagnetic minerals due to the best magnetic field value from the roller surface that is, 0.89 to 2.59 T. Prediction analysis was performed on FEMM data using artificial neural network (ANN) modelling technique. Further, the design calculations of lab scale PRMS in terms of power requirements and belt tensions were addressed. The fabricated PRMS was tested on paramagnetic mineral (hematite ore) assayed 51.24% of Fe, 10.20% of SiO2, and 2.98% of Al2O3 for different roller speeds and the belt thickness. The result showed that, at 0.5 mm belt thickness with 180 rpm roller speed the fabricated lab scale PRMS works well in terms of improvement in the Fe content up to 59.5% at the concentrate along with the Fe recovery of 71.41%. The obtained results suggest that, the FEMM analysis is more suitable to optimize the effective magnetic roller for the PRMS. © 2021 The Society of Powder Technology JapanItem 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 UniversityItem Bending and vibration studies of FG porous sandwich beam with viscoelastic boundary conditions: FE approach(Taylor and Francis Ltd., 2023) Patil, R.; Joladarashi, S.; Kadoli, R.Bending and vibration characteristics of FG porous sandwich beam with viscoelastic boundary conditions are investigated. Complex shear modulus and associated loss factor are considered for the viscoelastic interlayer. The beam is constrained by viscoelastic supports (VES) at either end. Complex stiffness model is adopted for VES. The transverse deflection, natural frequency, loss factors, and mode shapes are obtained by varying VES stiffness. Furthermore, the study is extended to sandwich beams with various (H, O, V, and X) porosity patterns. The results convey that VES contribution in vibration damping is more predominant when the supports are less stiff (more viscous). © 2022 Taylor & Francis Group, LLC.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 Modelling and predicting the dynamic response of an axially graded viscoelastic core sandwich beam(KeAi Communications Co., 2023) Nagiredla, S.; Joladarashi, S.; Kumar, H.The present study explored the influence of axial gradation of viscoelastic materials on the dynamic response of the sandwich beam for structural applications. The finite element (FE) formulations are used to model and investigate dynamic response of the sandwich beam. The classical beam theory is used to develop the FE formulations and Lagrange's approach is considered to obtain the equations of motion (EOM). FE code is developed and validated with the existing literature and also conducted the convergence study for the developed FE method. Further, the influence of different viscoelastic materials and boundary conditions on the dynamic response of the sandwich beam is investigated. Four different axial gradation configurations of viscoelastic materials are considered for the present work to explore the influence on natural frequency, loss factor and frequency response of the sandwich beam. The modeled axial gradation of viscoelastic material has displayed a considerable impact on the peak vibrational amplitude response of the sandwich beam for all the boundary conditions and these configurations improved the damping capabilities at different configurations for the structural applications. © 2023 China Ordnance SocietyItem Influence of magneto-rheological fluid pocket configuration on the dynamic response of the composite sandwich beam(Taylor and Francis Ltd., 2024) Nagiredla, S.; Joladarashi, S.; Kumar, H.The present study investigated the influence of magnetorheological (MR) fluid pocket configuration and magnetic field intensity on the dynamic response of the composite sandwich beam under various boundary conditions. The classical beam theory is used to develop the finite element (FE) formulations for the composite sandwich beam element and it is validated with the available literature. Four MR fluid pocket configuration types are considered. The configuration types include 1/4th, 1/2th, 3/4th and the full length of the MR fluid pockets at different locations. Further, a detailed study of the influence of each MR fluid pocket configuration type on the natural frequency, loss factor, and frequency response are presented. The maximum 32.27% of deviation in the first fundamental frequency is observed for the simply-supported boundary condition. From the results obtained, it is concluded that the length and location of the MR fluid pocket have a considerable impact on the dynamic response and also observed that the effect of the configuration depends on the type of boundary condition used. © 2022 Taylor & Francis Group, LLC.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.