Faculty Publications
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Publications by NITK Faculty
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Item Numerical Investigation on Factors Affecting the Performance of Roof Bolts for Continuous Miner Working(Springer Nature, 2020) Tejeswaran, K.M.; Murthy, C.S.N.; Kunar, B.M.Optimum support design of roof bolts based on axial load of the bolt plays the major role for effective development of coal seam with continuous miner. Axial load on the roof bolts gives a clear understanding of the behaviour of roof bolts in different working conditions. Therefore, estimation of axial load on the bolts is important for supporting the immediate roof, helps in higher production, productivity and safety. By using the software FLAC 3D, the axial load for different gallery widths and working depths was estimated. From the simulation results, it was observed that for shallow depths of 100 and 200 m, the axial load acting on the bolt is 15% of the bolt capacity at gallery widths of 4 m and 5 m. Whereas for moderate depths 300 m and 400 m, its value is found to be 75% at gallery widths 6 m and 7 m. But, for deeper depths of 500 m and more, its values reaches maximum capacity of roof bolts. Also, the roof convergence in junction, for moderate and deeper depths is 80 mm to 150 mm, whereas for shallow depths its value is 10–25 mm, at 6 m, 7 m and 8 m gallery widths. © 2020, Springer Nature Switzerland AG.Item Accurate Estimation for Stability of Slope and Partition Over Old Underground Coal Workings Using Regression-Based Algorithms(Springer Science and Business Media Deutschland GmbH, 2022) Dorthi, K.; Kumar, A.; Ram Chandar, K.R.Numerical modeling simulation has found to be best solution for predicting slope and partition stability over old underground coal workings. But it has taken huge time to complete a single simulation model. In this regard, machine learning-based framework is used to predict the stability of old galleries. A case study is taken up in opencast mine and simulation is carried out using numerical model and machine learning-based framework. Framework has shown an overall accuracy of 94–95% for different slope and partition stability. Framework shows a speedup of 2366 × against numerical simulator. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Numerical Modeling on Buckling Behavior of Structural Stiffened Panel(Springer Science and Business Media Deutschland GmbH, 2023) Alagundi, S.; Palanisamy, T.Stiffened panels are essential building elements in weight-sensitive structures. They have various applications in marine, aircraft, and other structures. Plate structures can undergo buckling when subjected to axial compression loads and then exhibit out of plane displacements. The present work aims to study the buckling behavior of the stiffened panel. The finite element model of the stiffened panel is developed, and buckling analysis is performed using ANSYS software. This model is validated with the published experimental work. Once the model is validated, total of 320 numbers of models of stiffened panels with varying plate thickness, stiffener height, stiffener thickness, and distance between stiffeners are modeled in ANSYS-2020, and buckling analysis is performed. An artificial neural network model is proposed to predict the buckling load of the stiffened panel. Neural network model is created in MATLAB software, and it is trained, tested, and validated, and its performance is checked by statistical relations like coefficient of correlation and mean square error. Proposed ANN model shows high accuracy in the prediction of buckling load. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item An Improved Finite Element Based Approach to Predict Single Track Geometry During Laser Directed Energy Deposition(Springer Science and Business Media Deutschland GmbH, 2025) Chaurasia, J.K.; Gurugubelli, R.C.; Jinoop, A.N.; Bontha, S.; Paul, C.P.; Bindra, K.S.This paper reports development of a two-dimensional transient finite element based numerical model to predict dimensions of deposited single track during laser directed energy deposition (LDED) of Inconel 625 (IN625) superalloys. The numerical model in the paper is based on two steps where first melt pool dimensions are determined using a transient thermal simulation. The second step accounts for the material addition, where the elements are activated based on the calculation of excess enthalpy. The numerical model is based on the fundamental principles of energy and mass balance. The numerical model also incorporates the fluid dynamics effects by multiplying the correction factor to the thermal conductivity of the material above melting temperature and also compares the track dimensions without considering the correction factor. A comparison of the track height and width obtained from the numerical model at Cf = 1 and 2.5 with experimental measurements was done. The maximum absolute percentage error in the numerical model considering the fluid dynamics effects (Cf = 2.5) is 5% in track height and 9% in track width. The percentage errors in the case of numerical model without fluid dynamics effects (Cf = 1) is 13% in track height and 16% in track width. The numerical model without considering the fluid dynamics effect is found to overpredict the track dimensions in all the cases. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Response of Offshore Wind Turbine Monopile Foundation Under Action of Wind Load and Sea Waves: Numerical Analysis(Springer Science and Business Media Deutschland GmbH, 2025) Sah, B.; Sridhar, G.Offshore wind turbine, being one of the most important renewable energy sources globally, has witnessed the construction of numerous offshore wind farms. These are established in offshore areas due to the steadier and stronger winds compared to onshore environments. Among the diverse fixed offshore foundation systems utilized for wind turbines including gravity, caisson, tripod, monopile, jacket, and suction, the monopile foundation emerges as the predominant choice, especially well-suited for sea beds with depths up to 35 m. However, understanding the behavior of monopile foundations under the combined influence of cyclic wind and sea waves remains limited. Throughout the 25 year lifespan of a turbine, cyclic loading continuously affects the foundation, potentially altering soil stiffness and system frequencies. To address this issue, numerical modeling using finite element method program is employed in this study. Through cyclic loading simulations, the response of monopile foundations to wind and sea waves is thoroughly investigated. Parametric studies also conducted to explore the impact of factors such as soil properties and loading conditions. The findings of this study contribute to a deeper understanding of monopile foundation behavior under dynamic environmental conditions, offering valuable insights for design and optimization of offshore wind energy projects. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Stability of horizontal oil well - A Jointed Rock model approach(2011) Anantharamu, A.; Singh, T.N.; Venkat Reddy, D.Advancement in technology has paved different ways for the extraction of oil. Drilling of wells, production and injection of fluids results in the alteration of pre-existing stress field in a reservoir. The current study is undertaken to analyze the stability of horizontal oil wells with the change in radius of the well, Poisson's ratio, saturation density, permeability and also to find stress distribution around horizontal oil wells drilled in different reservoir conditions, stress distribution before and after production and also to assess the effect of stress distribution on the stability. The knowledge of stress distribution and its redistribution with change in reservoir conditions can help in selecting well locations and orientations for maximum sweep in reservoirs. Displacement of the particles gives the direction of fracture propagation. As the particle size increases, fracture propagation increases. The stability analysis has been done using Jointed Rock method of Numerical Modeling. Numerical models are mathematical models that use numerical time-stepping procedure to obtain the models behavior over time. The results of the model are shown to agree qualitatively with field observations. The extent of stress distribution is dependent on radius of the well, pore pressure in the reservoir, fracture density of the reservoir and drilling direction. Horizontal wells drilled in highly fractured reservoirs will be less stable. In case of anisotropy, since the stability is very less we must reduce the radius of the well in order to increase the FOS and hence the stability. © 2011 CAFET-INNOVA TECHNICAL SOCIETY.Item Numerical modeling of oil spill in the proximity of Krishna- godavari coastal wetlands(CESER Publications Post Box No. 113 Roorkee 247667, 2014) Hegde, A.V.; Labeeb, C.K.Coastal wetlands are one of the important natural resources. They include saltwater and freshwater wetlands located within coastal watersheds. These wetlands act as breeding places and provide food and nutrients to many organisms, control flood and purify water. The paper discusses the prediction the trajectory of a possible oil spill in the nearness of the coastal wetlands of Krishna-Godavari delta in Andhra Pradesh, India. Krishna Godavari oil field was recently explored and rigging for oil has already begun. Here numerical modeling for oil spill trajectory is carried out using the software GNOME (General NOAA Operational Modeling Environment) developed by NOAA (National Oceanic and Atmospheric Administration) of United States. Three scenarios - 10000 barrels, 5000 barrels and 1000 barrels of medium crude oil spill are run on the GENOME model for possible spill locations of Krishna Godavari oil field. The simulation is carried out for the month of November 2012, when the regional current and wind conditions are hostile. The study provides an understanding of the most probable trajectory of the slick and forecasts if it reaches the sensitive Krishna-Godavari coastal wetlands, and thereby helps to take proper oil spill mitigation measures to conserve the valuable wetlands. © 2014 IJED.Item Slope stability monitoring in opencast coal mine based on wireless data acquisition system-a case study(Science Publishing Corporation Inc ijet@sciencepubco.com, 2018) Dorthi, K.; Ram Chandar, K.R.Real time monitoring of slope failures is necessary to maintain the stability of slopes in open cast mines. A 3-level structure of Wireless Data Acquisition System (WDAQ) is developed for real time monitoring of slope deformation and analysis of data. In this paper, a case study is presented in a large opencast coal mine. Deformation in the slopes with slope angles of 49°, 53°, 58°, 64°, 68° and 70° is monitored over old underground workings. The deformation caused due to the external load like movement Heavy Earth Moving Machinery (HEMM). Maximum deformation was 1.57mm for slope angle of 70°. It can be observed that the deformation increased with increased slope angle. This paper also describes that the validation of data based on WDAQ with the conventional method of monitoring as well as numerical modeling. The data obtained using WDAQ is in close to other two methods. The variation is around 11%. © 2018 Authors.