Conference Papers

Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506

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    CAD tools for antennas
    (2008) Bhavatharini, S.; Raghavan, S.; Sriram Kumar, D.S.
    There are a number of CAD tools available in the market today for microwave designs. They enable the designer to try his hand at even very complex design very easily and quickly. They optimize MEMS designs prior to fabrication, which reduces prototype development cycle time and cuts manufacturing costs. This paper attempts to list a few of the popular CAD tools that are available in the market today and highlights on their special features that makes each tool unique. © 2008 IEEE.
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    On electric fields in belted cables and 3-phase gas insulated cables
    (2011) Punekar, G.S.; Nafo, T.; Kishore, N.K.
    The electric field distribution in Belted Cables and 3-phase gas insulated cables (GIC) enclosed in a common ground enclosure is analyzed and presented in this paper. The electric fields in this type of GIC are analogous to those of 3-phase belted cables. Unlike 3-phase screened cables, the stress distribution in belted cables is not radial. With time varying voltages (power frequency voltage variations; quasi-static voltages) the stress distribution in the cable insulation changes, not being radial. The electric stress distribution is expected to show systematic, revolving effect. This revolving effect is important as the location of maximum stresses keep on shifting. Also, as a secondary effect, the revolving e-field results into electric-field-winds which can add to the particle movements in the gas insulated cables. The literature acknowledges that particle movements in the gas insulated system can have deleterious effect on the over all system insulation strength; which partly get impetus from e-field-winds. The stresses in such a cable are analyzed using open source software Finite Element Method Magnetics (FEMM). The results presented show that the field distribution over a cycle (of 50 Hz) at discrete time intervals are thought to be having a great educational value, giving a feel of electric field variation in (i) belted cables and (ii) GIC with common enclosure. The computed results of electric stress and potential distribution using FEMM are compared with available results based on CSM models to validate the present results where ever possible. © 2011 IEEE.
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    Theoretical and numerical study of symmetric, in-plane, free vibration of Timoshenko portal frame with open crack
    (Chinese Society of Theoretical and Applied Mechanics ICF13@cstam.org.cn, 2013) Satyavan, N.M.; Kumar, S.; Murigendrappa, S.M.
    The local flexibility introduced by cracks changes the vibration behaviour of the structure and by examining this change, crack severity can be identified. This paper presents the natural frequencies of symmetric, in-plane free-vibrations of Timoshenko portal frame with and without open crack for different boundary conditions. Cracked segment is modelled as two segments connected by a massless torsional spring. Considering appropriate compatibility requirements at the crack section in any one of segments and at the junction of two segments, the characteristic equations are established for corresponding boundary conditions and solved for natural frequencies by numerically. Crack location ranging from 20% to 70% of length of segment and crack size ranging from 20% to 60% of depth have been considered. Results obtained analytically are compared numerically using standard commercially available finite element software. The frame has been modelled by using quadratic quadrilateral shell elements and quarter-point singular elements are employed around the crack-tip. It is observed that as expected, with increase in crack depth the change in frequencies of the frame with and without crack increases. The maximum difference between the analytical and numerical results is 7.09% for all the cases considered, which proves usefulness of the data.
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    Numerical study on fracture behavior of alkali activated concrete mixes for different beam sizes
    (Elsevier Ltd, 2023) Annappaswamy, G.M.; Channappa, T.M.; Prashanth, M.H.
    The present study considers the use of AAC mixes, since the raw materials that are being used to produce concrete are non-renewable natural resources, particularly Ordinary Portland Cement (OPC). Also, production of OPC contributes a greater amount of CO2 to the environment. Hence, an attempt has been made to study alternative construction materials keeping in mind sustainable development. The present numerical study compares the fracture behaviour and size effect of Alkali Activated Concrete (AAC) mixes with Ordinary Portland Cement Concrete (OPCC) mixes by numerically modelling the beams of AAC and OPCC using FEA software ABAQUS. Three different mixes of AAC, characterized by the variation of percentage volume of water-quenched slag (WQS) as a substitute for Natural sand (RS) and one OPCC mix, were studied. A three-point bending test was performed in ABAQUS for the beams of three different sizes, which are geometrically similar with constant thickness. Numerical simulation is performed under displacement control. Load versus CMOD graphs are plotted from the output data obtained from the numerical modelling. Fracture parameters such as Fracture energy (GF), Brittleness number (B), Characteristic length (lch), and Stress intensity factor (KIC) are then calculated from the obtained data and compared to understand the influence of fracture properties and size effect on the behaviour of structural elements since limited research works are available from the literature. From the results, it is observed that OPCC mixes show superior strength, high resistance to crack propagation, more toughness, and high fracture energy when compared to AAC mixes. AAC-50 concrete mix has shown better performance compared to the other two AAC mixes, i.e., AAC-0 and AAC-100. The results of this work can certainly be used to predict the non-linear behaviour of concrete and can be adopted in the design of structural elements. © 2023 Elsevier Ltd. All rights reserved.
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    Comparison of Stress Distribution of Graphene-Based Bioactive Material for Zirconia and Titanium by Applying Orthotropic Properties: A Finite Element Analysis
    (Springer Science and Business Media Deutschland GmbH, 2024) Singh, R.K.; Verma, K.; Kumar, G.C.
    This study employs finite element analysis to examine stress distribution at the bone–implant interface in graphene-based dental implants. Four implant models, encompassing titanium and zirconia with and without graphene coating, are assessed under axial and oblique loading. Considering their anisotropic nature, bone tissues are simulated as orthotropic, while implants are treated as homogeneous and isotropic. The study utilizes one-way ANOVA and Kruskal–Wallis tests for statistical analysis to compare stress distribution among implant groups. Results indicate superior von Mises stress distribution in graphene-based implants (A2 and A4) compared to the pure material group. The incorporation of graphene coating significantly reduces implant stresses under axial and oblique loads compared to titanium and zirconia. In conclusion, the study underscores the potential benefits of graphene-based implant models in optimizing stress distribution at the bone–implant interface, emphasizing the importance of suitable implant models and biomaterial selection for enhanced dental implant performance. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.