Faculty Publications

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Author: search.filters.author.Babu Narayan, K.S.Has files: No

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    Applicability of Meshfree Method in Computational Solid Mechanics
    (Springer, 2024) Paul, K.; Babu Narayan, K.S.
    Meshfree methods are powerful computational tools that offer several advantages over conventional finite element methods. Based on a cloud of points, meshfree methods are easy to construct and provide great adaptivity. Among these methods, the element free Galerkin (EFG) method is widely used for solving solid mechanics problems. In this study, the influence of nodal density on accuracy and computational time is investigated using the EFG method for an axially loaded 1D bar. The method is also applied to a 2D cantilever beam that is subjected to a point load at the free end, and the essential boundary conditions are enforced using Lagrange multipliers. A MATLAB-based program is used to obtain displacement profiles along the length of the bar. The study evaluates the accuracy and computational cost of the EFG method and reports a good agreement between the obtained results and the exact analytical solution. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
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    Shape optimization and assessment of wind induced stresses in domes
    (2009) Babu Narayan, K.S.; Yaragal, S.C.; Tamura, Y.
    Domes are popularly used for column free areas. They are employed as covers to reservoirs and treatment units and also as containment in nuclear reactors. Inverted domes are popular as foundations. This paper demonstrates the need and scope for optimization of domes by formulating and solving the problem by use of calculus. A simple but elegant method is suggested for determination of wind stresses by statics which compares very well with that obtained by rigorous method.
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    Stochastic Analysis to Assess Uncertainty in Pushover Analysis to Modeling Methods
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2014) Panandikar, N.; Babu Narayan, K.S.
    The pushover analysis is a nonlinear static procedure wherein monotonically increasing loads are applied to the structure. It is a popular tool for seismic performance evaluation of existing, as well as new, structures. In the literature a lot of research work has been carried out on conventional pushover analysis and, after knowing deficiencies, efforts have been made to improve it. However, actual experimental test results to verify the analytically obtained pushover results are rarely available. Also, the procedure involves certain approximations that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. In this paper, an ttempt is being made to assess the uncertainty of pushover analysis results to modeling methods and results compared with experimentally obtained results based on tests carried out on a G+2 storied RCC framed structure. Stochastic analysis is carried out by considering uncertain parameters as the strength of concrete, strength of steel, cover to the reinforcement, hinge location and hinge length which are randomly generated and incorporated into the analysis. The hinge lengths are found using various hinge length formulations available in literature. The results are then compared with experimental observations. © 2014 American Society of Civil Engineers.
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    Making sense of high dimensional concrete data - A statistical approach
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Manoj, A.; Babu Narayan, K.S.
    Performance of concrete is dependent on a number of factors. It is difficult to understand the influence and interrelationship among these variables, when there are many. Dimensionality reduction techniques can yield the best possible data interpretation based on the variance in data, without loss of much of original information. This paper presents the application of dimensionality reduction technique for analysis of data and decision making in the field of Concrete Technology. © Published under licence by IOP Publishing Ltd.
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    Meshfree Methods in Computational Mechanics—State of the Art
    (Springer Science and Business Media Deutschland GmbH, 2024) Paul, K.; Babu Narayan, K.S.
    The finite element method (FEM) has widespread use in solving problems in computational mechanics and applied sciences. However, researchers continue to develop and implement new numerical methods to solve problems that involve complex geometry, material non-linearity, and fracture mechanisms, including crack formation and propagation with moving and discontinuous boundaries. Meshfree methods have seen a significant increase in their application to solve partial differential equations (PDE). These methods involve modelling and solving procedures that depends on a cloud of nodes or points for geometry representation and discretization. In the field of computational fracture mechanics, the meshfree nature of meshfree methods has gained considerable attention for modelling two-dimensional and three-dimensional crack growth. While FEM uses interpolation methods to formulate shape functions, meshfree approaches use approximation methods. This review aims to examine the developments, utility, limitations, and potential for refinements of meshfree techniques. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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    Performance enhancement of RC frames using welded wire fabrics - An experimental investigation
    (2010) Prashanth, M.H.; Chinnagiri Gowda, H.C.; Babu Narayan, K.S.; Ramana, K.V.
    The paper presents the performance enhancement of RC frames using welded wire fabrics to appraise beneficial effects of welded wire fabrics as lateral reinforcement in Reinforced Concrete elements. The RC frames subjected to lateral loading have been simulated to rhombus frame with vertical loading. The experimental investigation has been done on rhombus frame with vertical loading. Experimental program involved details of test specimens, test set-up and instrumentation. Comparison of conventional bare frames has been done for frame with welded wire fabrics as lateral reinforcement at discrete zone and frame with welded wire fabrics as lateral reinforcement throughout the length for the same volume fraction. Results of Experimental investigation have been reported from which the discussions and conclusions had been drawn. © 2010 Cafet-Innova Technical Society.
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    Profiled sheets - the optimum vs the oft used
    (Techno-Press, 2010) Babu Narayan, K.S.
    Profiled sheets are used extensively in roofing, cladding, sheet piling and containments. Profile development is increasingly rapidly owing to advancement in materials and construction technology. The resistance to longitudinal bending is proportional to the depth and thickness and depends greatly on the profile itself. The strength of the profiled sheet in longitudinal bending is proportional to the depth of corrugation, thickness and on the profile itself. More often than not profiles are repetitive and most popular being of the sine wave form. Hence it may be assumed that if a quarter of the best form is determined, the most optimum profile is known. It is calculated that the strength/unit length of the most widely used sine wave form is in agreement with the best profile suggested by the calculus of variations.
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    Studies on concrete cylinders subjected to elevated temperatures
    (2010) Babu Narayan, K.S.; Anil Kumar, G.; Chandrakala, C.; Shashikumar, H.M.; Venkataramana, K.; Yaragal, S.C.; Chinnagiri Gowda, H.C.; Reddy, G.R.; Sharma, A.
    Concrete is a poor conductor of heat, but can suffer considerable damage when exposed to fire. Concrete in structures is likely to be exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. Unraveling the heating history of concrete is important to forensic research or to determine whether a fire exposed concrete structures and its components are still structurally sound or not. Assessment of fire damage concrete structures usually starts with visual observation of color change, cracking and spalling. On heating, a change in color from normal to pink is often observed and this is useful since it coincides with the onset of significant loss of concrete strength. This work reports the characteristics of concrete at elevated temperatures. Popular normal strength grades (M20, M25, M30, M35, M40 and M45) produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm diameter and 300mm height cylinders) to obtain more meaningful and realistic data. In the preliminary phase 150 mm diameter and 300mm height cylinders were cast, cured and tested by destructive method for gathering data on strength characteristics. Later these test samples were subjected to elevated temperatures ranging from 100°C to 800°C, in steps of 100°C with a retention period of 2 hours. After exposure, weight losses were determined and then again destructive tests were conducted to estimate the residual split tensile strength. Test results indicated that weight and strength significantly reduces with an increase in temperature. © 2010 CAFET-INNOVA TECHNICAL SOCIETY. All rights reserved.
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    Strength retention characteristics of concrete cubes subjected to elevated temperatures
    (2010) Yaragal, S.C.; Clarke, K.S.; Mahesh Babu, K.; Ashokumar, S.; Venkataramana, K.; Babu Narayan, K.S.; Chinnagiri Gowda, H.C.; Reddy, G.R.; Sharma, A.
    Concrete in structures is likely to be exposed to high temperatures during fire. The relative properties of concrete after such an exposure are of great importance in terms of the serviceability of buildings. The probability of its exposure to elevated temperatures is high due to natural hazards, accidents and sabotages. Therefore, the performance of concrete during and after exposure to elevated temperature is a subject of great interest to the designer. Physical changes like cracking, colour change, spalling and chemical changes like decomposition of Ca(OH)2 and the C-S-H gel take place when subjected to elevated temperatures. This work reports the characteristics of concrete at elevated temperatures. Popular normal strength grades (M20, M25, M30, M35, M40 and M45) produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm cubes) to obtain more meaningful and realistic data. In the preliminary phase 150 mm cubes were cast, cured and tested by destructive method for gathering data on strength characteristics. Later these test samples were subjected to elevated temperatures ranging from 100°C to 800°C, in steps of 100°C with a retention period of 2 hours. After exposure, weight losses were determined and then again destructive tests were conducted to estimate the residual compressive strength. Test results indicated that weight and strength significantly reduces with an increase in temperature. © 2010 CAFET-INNOVA TECHNICAL SOCIETY.
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    Studies on normal strength concrete cubes subjected to elevated temperatures
    (2010) Yaragal, S.C.; Babu Narayan, K.S.; Venkataramana, K.; Kulkarni, K.S.; Gowda, H.C.C.; Reddy, G.R.; Sharma, A.
    Concrete in structures is likely to be exposed to high temperatures during fire. The probability of its exposure to elevated temperatures is high due to natural hazards, accidents and sabotages. Therefore, the performance of concrete during and after exposure to elevated temperature is a subject of great importance and interest to the designer. Popular normal strength grades of concrete produced by Ready Mix Concrete (RMC) India, Mangalore have been used in production of test specimens (150 mm cubes), cured and tested by destructive method for gathering data on strength characteristics. Later, these test samples were subjected to elevated temperatures ranging from 100 C to 800 C, in steps of 100 C with a retention period of 2 hours. After exposure, weight losses and the residual compressive strength retention characteristics are studied. Test results indicated that weight and strength significantly reduces with an increase in temperature. Residual compressive strength prediction equations are proposed for normal strength concretes subjected to elevated temperatures.