Conference Papers

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

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Author: search.filters.author.Hebbar, H.S.

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    Studies on the effect of ball burnishing parameters on surface hardness of HSLA dual-phase steels using factorial design
    (Indian Institute of Metals, 2008) Rao, D.S.; Hebbar, H.S.; Komaraiah, M.; Kempaiah, U.N.
    Burnishing is used increasingly as a finishing operation which gives additional advantages such as increased hardness, fatigue strength and wear resistance. Experimental work based on 34 factorial design was carried out to establish the effects of ball burnishing parameters on the surface hardness of HSLA dualphase steel specimens. Statistical analysis of the results shows that the speed, feed, lubricant and ball diameter have significant effect on surface hardness.
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    Finite element simulation of exit hole filling for friction stir spot welding - A modified technique to apply practically
    (Elsevier Ltd, 2014) Vinayak, V.; Sanjeev, N.K.; Hebbar, H.S.; Kailas, S.V.
    Friction Stir Spot Welding (FSSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and/or a probe. Though it has proven its potential in joining difficult to weld materials, one of the drawbacks of process is prevalence of exit hole at the end of the process. In the recent past new techniques have been developed to eliminate this draw back by filling this unwanted hole. Determining the appropriate tool design and parameters to fill a hole for given situation is a challenge. The article demonstrates the effective method of obtaining these desired parameters a priory. A three dimensional (3D) model is developed in finite element (FE) commercial code DEFORM 3D/Implicit. It was found that internally filleted shoulders help in filling of holes. The obtained optimized process parameter (tool rotation speed of 900rpm, plunge velocity of 30mm/sec and plunge depth of 0.2 mm) for AA2024 plate (5mm thick) have potential to reduce number of experiments. © 2014 The Authors.
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    Investigations on the effect of various tool pin profiles in friction stir welding using finite element simulations
    (Elsevier Ltd, 2014) Vinayak, V.; Sanjeev, N.K.; Hebbar, H.S.; Kailas, S.V.
    Friction stir welding (FSW) is a solid state joining process which uses a rotating tool consisting of a shoulder and a pin/probe. The shoulder applies a downward pressure to the work piece surface, generates heat through the friction and leads to plasticization of materials in the vicinity of pin. During traverse the rotating tool mixes the adjacent material in the stir zone, creating a joint without fusion. The welding tool pin profile plays a major role in obtaining desirable weld. At present, research efforts are being made to gain a better understanding of the process, to explore different tool configurations, to optimize the set of process parameters and to widen the applicability of FSW and it variants. In this regard, having reliable finite element model that is capable of simulating FSW with minimal possible simulation time can turn out handy to reduce the number of physical experiments required in such studies and applications. The current work investigates a model based approach in knowing the effect of various tool pin profiles on temperature, stir zone and power consumed for welding. A three-dimensional (3-D) model is developed in finite element (FE) commercial code ABAQUS/Explicit using the Coupled Eulerian-Lagrangian (CEL) formulation, the Johnson-Cook material law and Coulomb's law of friction. The obtained results help in arriving at better tool designs. © 2014 Published by Elsevier Ltd.
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    Magnesium based biocomposites for biomedical applications - A review
    (American Institute of Physics Inc. subs@aip.org, 2020) Moudgalya, K.V.S.; Hebbar, H.S.
    Magnesium based materials are explored extensively in recent times because of its excellent properties like biocompatibility, biodegradability, low density and low elastic modulus. The excessive degradation rate of magnesium-based material has led to enormous research, by employing different techniques, for the enhancement of corrosion resistance. Recently, a lot of work has been done to develop a ceramic reinforced Mg-based composite which satisfies mechanical, corrosion and biocompatibility properties required for orthopedic applications. This review is focussed to highlight the advances in the development of Mg-based composites, specifically on hydroxyapatite and bioglass reinforced composites. © 2020 Author(s).