Faculty Publications
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Item Three dimensional modeling of geocell using membrane elements by considering the actual curvature(American Institute of Physics Inc., 2021) Vibhoosha, M.P.; Bhasi, A.Railway Networks are popular world wide because of its ride quality and low cost. In order to meet the ever growing demand, the track operational efficiency has to be improved with minimal maintenance and infrastructure cost. By providing a three dimensional honey comb structure known as geocell on track substructure, the lateral deformation of the ballast and sub ballast can be effectively reduced and the overall stability is improved. The 3D modeling of geocell is complex as it involves interaction between geocell walls and the fill material inside. Different constitutive models were used for both geocell and infill material with suitable interaction properties. By using the membrane elements the hexagonal shape of geocell was simulated. In this paper, full 3-d finite element analyses were carried out using developed numerical model to study the lateral deflection of geocell reinforced subballast system. Also a comparison was made between 3D and 2D numerical models. © 2021 American Institute of Physics Inc.. All rights reserved.Item Gamma radiation shielding characteristics of concrete mixes-the state of art(2013) Santhoshkumar, M.; Narasimhan, M.C.; Karkera, B.In this paper, initially the interaction of gamma radiation with materials in general and concrete in particular are discussed. The state-of-art attempts made in different parts of the world, in improving the gamma radiation shielding properties by incorporating alternate/additional ingredients in concrete mixes are discussed. Such incorporation may be in terms of changes in any of the binder, coarse or fine aggregate components of the concrete mixes. The usage of materials such as mineral admixtures, high density solid wastes and fibres is also reported. The possible use of other mineral materials in concrete mixes for enhanced shielding performance against gamma radiation in nuclear installations is brought out. A brief review of the mix design parameters controlling shielding performance of concrete mixes is also cited. An attempt has been made to compare the shielding performances of different concretes by comparing their linear attenuation co-efficient values (μ) reported in the literature. In view of the exponential surge in γ-ray sources in nuclear industry this review is relevant to save the planet earth from an impending global disaster as well as introducing radiation in industries, food preservation, nuclear medicine and many other such applications. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.Item Graph energy centrality: a new centrality measurement based on graph energy to analyse social networks(Inderscience Publishers, 2022) Mahadevi, S.; Kamath, S.S.; Shetty D, P.D.Critical node identification, one of the key issues in social network analysis, is addressed in this article with the development of a new centrality metric termed graph energy centrality (GEC). The fundamental idea underlying this GEC measure is to give each vertex a centrality value based on the graph energy that results from vertex elimination. We show that the GEC of each vertex is asymptotically equal to two for cycle graphs and exactly equal to two for complete graphs. We further demonstrate that star graphs can be ranked using only two GEC values, whereas path graphs can be ranked using a maximum of ⌈n+12 ⌉ values. The proposed algorithm takes O(n3) time complexity to rank all vertices; hence an optimised algorithm is also being proposed considering only a few classes of graphs. The proposed algorithm ranks the nodes based on the collaborative measure of eigenvalues. © 2022 Inderscience Enterprises Ltd.. All rights reserved.Item Analysis of Geocell-Reinforced Stone Column-Supported Embankment Considering Soil-Structure Interaction(Springer, 2022) Vibhoosha, M.P.; Bhasi, A.; Nayak, S.Geocells are a superior form of reinforcement due to their cost-effectiveness and three-dimensional confining properties. The effect of the basal geocell layer on the performance of the stone column-supported embankment was evaluated in this paper by carrying out time-dependent coupled analyses considering the geocell-infill soil interactions. The various parameters, such as arching, stress concentration ratio, surface settlement, column bulging characteristics, and the influence of various types of infill materials and drainage blanket thickness on column-supported embankment behavior, were analyzed. The load transfer mechanism was quantified using the term stress concentration ratio, and with the use of geocell mattress above stone columns, the stress concentration ratio increased by 1.5 times that of ordinary stone columns. Also, it was observed that compared to ordinary stone column-supported embankment, the combination of stone columns with geocell-sand mattress resulted in a further reduction of the foundation settlement by 15%. Analysis results showed that the arching behavior is not predominant in geocell-reinforced columnar structures. The various analytical methods like Guido et al. (1987), Low et al. (1994), and Abusharar et al. (2009), which were developed for geosynthetic reinforced columnar embankments, were found to significantly under-predict the stress reduction ratio values with geocells. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.