Faculty Publications
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Publications by NITK Faculty
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Item Subsidence Analysis for Old Abandoned Board and Pillar Coal Mines Using ANSYS and Monte Carlo Simulation(Pleiades Publishing, 2024) Akhil, A.; Pal, S.K.; Tripathi, A.K.; Kumar, G.Abstract: This research paper will cover the possible causes which can lead to subsidence above old abandoned board and pillar coal mines at a shallow depth. The research includes the calculation and analysis of the factor of safety for pillars using ANSYS and Monte Carlo Simulations for ascertaining subsidence. An old abandoned coal mine of South Eastern Coalfields Ltd. (SECL, a subsidiary of Coal India Limited) was considered for the study of coal pillar fatigue and eventual crushing of pillars over a long duration of time, simulation analysis of stress and strength of coal pillars over a long period, change in behavior of factor of safety as the dimension of the pillars changes. © Pleiades Publishing, Ltd. 2024.Item Stability Analysis of Overburden Dumps over Old Underground Workings Using Artificial Neural Networks(Pleiades Publishing, 2024) Harish, P.; Chandar, K.R.Abstract: Stability of overburden dump slopes is a crucial aspect in designing secure and cost-effective dumps. The Strength Reduction Factor (SRF) serves as a widely used term to assess dump stability. This paper focuses on developing an Artificial Neural Network (ANN) model capable of predicting SRF for overburden dumps situated above existing underground workings. To construct the model, a dataset comprising 96 numerical simulations of overburden dumps generated through the finite element method was utilized. A neural network architecture with three layers of forward-backward propagation was utilized, containing hidden neurons to analyze simulations during training, validation and testing stages. The input parameters for studying overburden dump slopes over underground workings included dump slope height (Sh), dump slope angle (), cohesion (C), friction angle (Ø), unit weight () of the dump material, depth of working from the surface (D), centre-to-centre pillar distance in underground workings (C-C), and gallery width (Gw). The ANN predicted results were compared with the outcomes derived from numerical simulations of overburden dump slopes above underground workings. The study highlights that the developed ANN model in this research proves highly effective in handling and designing complex overburden dump slopes. The obtained results indicate a Mean Square Error (MSE) of 0.0595 and a coefficient of determination (R) of 0.883, both of which are considered acceptable. © Pleiades Publishing, Ltd. 2024.Item Torque generation in lightweight four rotor magnetorheological brake(Springer, 2024) Kadam, S.; Kariganaur, A.K.; Kumar, H.Non-Newtonian behaviour of the Magnetorheological (MR) fluid under the influence of external magnetic field can be commissioned to design various applications such as MR brake, damper, and clutches, etc. Better design strategies, material selection and characterization led to realize the potential of MR brakes to replace conventional brakes. The present study emphasises on developing lightweight (1.8 kg) multi-rotor MR brake (MMRB). Finite element method magnetics (FEMM) software is utilized to determine the material required for a single-rotor MRB. FEMM material selection analysis is incorporated into the modeled MMRB, and the nature of magnetic flux density throughout the MR gap was obtained. Magnetic circuit analysis of the proposed brake is carried out to find torque estimation using analytical equations and Bingham plastic model. The proposed brake is fabricated and characterized using commercial MRF (132 DG, Lord Corporation). The study compares the torque outputs obtained experimentally with finite element analysis (FEA) and analytical approach. The average maximum magnetic flux density through FE analysis is found to be 0.45 T @ 3 A current. The average error between FE obtained and experimentally obtained torque output of the brake is around 5%. Further, an alternate design is proposed by utilizing same rotor diameter and number of electromagnetic coils. The new design is lighter in weight (0.8 kg) and exhibits enhancement in the torque output and torque to weight ratio by around 31% and 55%, respectively than the present design. © Indian Academy of Sciences 2024.Item Analysis of spur gears drilled with radial holes on teeth surface for effective weight reduction(Springer Science and Business Media Deutschland GmbH, 2025) Sutar, S.S.; Kumar, G.C.; Doddamani, M.Optimizing the geometry for efficient material utilization and gear weight reduction involves strategically removing material from gear teeth. This present study examines the stresses induced in the gears featuring radial holes within the gear tooth focused on lightening the weight of conventional gears. Radial holes are introduced at varying depths from the top of the gear tooth. The analysis uses ANSYS to assess the stresses in a conventional gear tooth and also the tooth with radial holes. Examining stress magnitudes near the gear root under similar loading and boundary conditions is critical and interesting. A complementary photoelastic approach is implemented, and stress distribution in these gears is confirmed to ensure the findings of finite element analysis. This approach retains the stress distribution while achieving a notable 6.7% reduction in volume compared to a conventional AGMA spur gear. Moreover, these radial holes are envisaged to contribute to adequate gear lubrication and cooling through fluid motion. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2024.Item Vibration and Stability Characteristics of Functionally Graded Plates Subjected to Localized Edge Loadings(Springer, 2025) Swaminathan, K.; Hirannaiah, S.; Rajanna, T.In this article, the influence of various types of localized in-plane edge loadings on vibration and stability characteristics of Functionally Graded Material (FGM) plates have been studied by developing finite element (FE) code in FORTRAN. Due to the complex arrangement of plates and situations arising during the real time application, loads acting on the member are not always uniform, rather nonuniform or localized in nature. For a such loading and boundary condition, the stress distribution within an element is highly non-uniform in nature. Therefore, the buckling loads are evaluated by dynamics approach. Here, in this study FGM plate is modelled using eight-noded isoparametric element with five degrees of freedom at each node. In the FE formulations, the influence of shear deformation and rotary inertia are included. In the FGM plate, the effective materials properties are assumed to vary in the thickness direction according to power-law distribution of volume fraction of the constituents. The analysis is carried out for four types of localized edge loads. Effect of different parameters such as boundary condition, side to thickness ratios, volume fraction exponent, load width ratio and the aspect ratio of the plate is considered to study the buckling characteristics of FGM plate. From the current study, it is mainly understood that the buckling characteristics of FGM plate of various volume fraction exponent is highly influenced by the position and width of localized in-plane edge loads. © The Institution of Engineers (India) 2024.Item Slope Stability Analyses and Design for a Telecommunication Tower Site in Kodagu—Limit Equilibrium and Finite Element Approach with Spatial Data Integration(Springer Science and Business Media Deutschland GmbH, 2025) Menon, V.; Anjana, S.; Kolathayar, S.This paper examines slope stability issues at the All-India Radio Telecommunication tower site in Kodagu, Coorg, Karnataka, India, where the hillock on which the tower stands has shown signs of instability after the monsoon of 2022. This study proposes reclamation strategies to mitigate future landslips in the region. A spatial analysis utilizing open-source Digital Elevation Models and Scoop3D software was performed to identify critical locations prone to landslips. The designs were assessed using the Limit Equilibrium method (LEM) and Finite Element method (FEM). Both static and pseudo-static conditions were considered in the analyses, with and without reinforcement, using the Limit Equilibrium Method and Finite Element Method. The proposed design aligns with the United Nations Sustainable Development Goals (SDGs) 9 and 11, demonstrating a significant increase in the Factor of Safety by more than 10%. The study recommends a geocell-based hybrid retaining system as a comprehensive solution to enhance slope stability and protect the site from future landslips. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.Item Analysis and Design of a Hybrid Reinforced Earth Retention System for Sustainable Slope Protection: A Case Study Using Limit Equilibrium and Finite Element Methods(Springer, 2025) Menon, V.; Kolathayar, S.This study proposes an innovative hybrid earth retention system to stabilize slopes for a road-widening project in Dakshina Kannada, Karnataka, India. The system combines soil nailing, geogrid reinforcement, geocell walls, and biotechnical stabilization—popular geotechnical techniques aligned with sustainable development goals. These methods were engineered synergistically to address the site-specific challenges of restoring a slope that experienced five major collapses during heavy rains, enabling both highway expansion and slope protection without disrupting traffic flow. Soil samples were collected, and laboratory tests were conducted to evaluate the engineering properties of the site soil. Boreholes were drilled at strategic locations and Standard Penetration Tests were performed. The analysis and design of the retention system employed both the Limit Equilibrium Method (LEM) and the Finite Element Method (FEM), utilizing GEO5 and OptumG2 software, respectively. A comparative analysis of these methods is presented, along with a non-linear regression model to establish correlations for soil nail parameters derived from LEM analyses. The study demonstrates the successful integration of geocell walls with soil nailing and geogrid reinforcement to support an unprotected embankment. The findings include the site reconnaissance report, reclamation strategies, and a detailed discussion of LEM and FEM analysis results, establishing the robustness and sustainability of the proposed hybrid retention system. © The Institution of Engineers (India) 2025.Item Experimental investigation of rotor wound multi disc magneto-rheological fluid brake(SAGE Publications Ltd, 2025) Bhat, S.H.; A, A.; Naveen, S.; Kumar, H.; M, A.Magneto-Rheological fluid (MRF), known for changing properties under a magnetic field, is ideal for brakes and dampers in magnetically controlled devices. This research presents a novel design for a 10-disc MR brake using in-house Magneto-Rheological Fluid (MRF), distinguished by its integration of electromagnet windings directly onto the brake shaft. Magneto-static analysis, performed using Finite Element Method Magnetics (FEMM) software, optimized the material selection and dimensions, enhancing the magnetic field distribution across the MRF gap and maximizing braking torque. The design, with rotor windings and a consistent MRF gap, generates a uniform magnetic field, significantly boosting performance. Theoretical braking torque was estimated using Bingham plastic model for MRF characterization, aligning well with experimental results. The compact 10-disc MR brake design, weighing 1.19 kg, shows robust torque performance across varying current levels. Remarkably, prior research had not integrated electromagnet windings directly on the rotor of MR brake, marking this study as pioneering in advancing MR brake performance. © The Author(s) 2025.Item High-Velocity Impact Behavior of Sandwich Composite with Compliant Skin and Sea Sand Strengthened Functionally Graded Core: Experimental and FE Approach(Korean Fiber Society, 2025) Mohan Kumar, T.S.M.; Joladarashi, S.; Kulkarni, S.M.; M, V.The present study investigates optimizing the impact resistance of novel functionally graded sandwich composites using numerical and experimental approaches. The high-velocity impact (HVI) behavior of functionally graded core sandwich composite (FGCSC) with bio-based jute/natural rubber skin and epoxy/sea sand (varying sea sand percentage 0, 10, 20 and 30%, and varying core thickness 10, 20, and 30 mm) functionally graded core. High-velocity impact (HVI) tests are performed using gas gun equipment at an impact velocity ranging from 200, 275, and 350 m/s. The weight residual and burnout method were used to test the gradience of core; both techniques showing significant correlation, and the variance in gradation could be observed. For FE analysis, the FGCSC are represented as deformable bodies, and the bullet is defined as a rigid body using commercially available dynamic explicit software. The HVI test results show that the proposed FGCSC has higher energy absorption capabilities, with core thicknesses of 30 mm and sea sand composition of 30%, resulting in a 1.80% improvement in energy absorption. A finite element study is also carried out to correlate the results, and the obtained results are in better agreement with the experimental findings. The damage analysis indicates that the developed FGCSC with flexible face sheets results in better damage mitigation. The findings suggest that FGCSCs are highly effective for bullet-proofing applications, including personal protective gear and structural components in defense. Further study and optimization could enhance the applicability of these sandwich composites in various protective and structural uses. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.