Faculty Publications
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Publications by NITK Faculty
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Item Influence of Coarse Aggregate Size and Type on the Design Thickness of Rigid Pavements for Indian Conditions(Springer Science and Business Media Deutschland GmbH, 2022) Bellary, A.; Suresha, S.N.The pavement quality concrete (PQC) is used in the construction of rigid pavements, commonly called concrete pavements. The coarse aggregates (CA) are the major constituents of the PQC mix, which influence the strength of the PQC mix. The strength of the PQC mix used in the construction of rigid pavements is one of the major factors that govern the design thickness of these pavements. In this study, an attempt has been made to characterize the influence of CA size and type on strength characteristics of the PQC mix experimentally. The crushed basalt and granitic CA are used in the preparation of the PQC mix. Also, three different nominal maximum aggregate size (NMAS) 19, 26.5 and 31.5 mm, are selected based on the IRC 44: 2017 guidelines. The experimental results are given as input in EverFE 2.24 software for determining the safe design thickness of rigid pavement over the design period. It is concluded that the safe design thickness of the PQC mix prepared using basaltic CA is comparatively lower than the PQC mix prepared using granitic CA for the same NMAS. Also, the safe design thickness of concrete pavement increased with an increase in NMAS irrespective of CA type. Thus, it is suggested to use stronger CA with lower NMAS based on the availability at the site. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.Item Mitigation of mutual coupling in 2 X 2 dual slant polarized MIMO antennas using periodic array of SRRs loaded with transmission line for LTE band 40(John Wiley and Sons Inc, 2020) Bellary, A.; Kandasamy, K.; Rao, P.H.2 X 2 dual slant polarized multiple input multiple output (MIMO) antennas with reduced mutual coupling is presented for polarization and spatial diversity. The design of printed periodic array of split ring resonators (SRRs) loaded with horizontal strip transmission line is proposed to mitigate the mutual coupling among the MIMO antenna elements. An equivalent circuit model, characterizes the effect of coupling between the array of SRRs and the loaded transmission line, which together reduces the near field coupling between the adjacent antenna elements. The additional horizontal strip at the bottom is utilized to seek the return current path to the ground plane. Polarization and spatial diversity is achieved by utilizing dual slant 450 polarized antenna elements with eight independent channels. All four dual polarized antenna elements are designed to operate with a VSWR of <2 for (2.3-2.4 GHz) Band 40. Dual slant 450 polarization is achieved by utilizing two printed planar bow-tie antennas in orthogonal orientation. Measured and simulated results shows by incorporating periodic array of SRRs loaded with transmission line a considerable mutual coupling reduction of 25 to 50 dB is achieved in E-plane, H-plane, and D-plane over the required band 40. An isolation of 30 dB and an average gain of 7.5 dB is measured for dual slant 450 polarized antenna elements. MIMO performance metrics in terms of envelope correlation coefficient and diversity gain are also investigated. © 2020 Wiley Periodicals LLCItem Influence of NMAS and groove depths on the static and fatigue shear performance of aggregate interlocking in PQC mixes(Taylor and Francis Ltd., 2022) Bellary, A.; Suresha, S.N.In the present study, a new test methodology is proposed to characterise the shear transfer ability of aggregate interlocking in pavement quality concrete (PQC) cylindrical specimens by conducting the direct shear test in the laboratory. The influence of the nominal maximum aggregate size (NMAS) and groove depth (GD) on shear strength (τ), joint shear stiffness (K) and fracture energy mode–II (G IIF) of aggregate interlocking in pavement quality concrete (PQC) are studied under static loading. A relationship between G IIF and K is determined. Also, shear fatigue test is conducted at higher stress levels to evaluate the effect of NMAS and GD on the performance of aggregate interlocking in PQC specimens at the grooved cross-section. From the Anderson–Darling statistic test, it is found that obtained fatigue results follow three-parameter Weibull distribution. The shape parameter (β) of the distribution is between one and two, which indicates that failure is due to wearing action. It is concluded that the proposed method in this research can be effectively used to evaluate τ, K and G IIF of aggregate interlocking in PQC specimens. Also, the use of larger NMAS in the PQC mix significantly improves the performance of aggregate interlocking under shear fatigue loading. © 2021 Informa UK Limited, trading as Taylor & Francis Group.Item Analysis of Wave Propagation Models with Radio Network Planning Using Dual Polarized MIMO Antenna for 5G Base Station Applications(Institute of Electrical and Electronics Engineers Inc., 2022) Bellary, A.; Kandasamy, K.; Rao, P.H.Dual polarized printed multiple input multiple output (MIMO) antenna for Band 42 (3.4 - 3.6 GHz) with wave propagation models is presented. Polarization and spatial diversity are achieved by utilizing two printed bow-tie antennas in orthogonal orientation. The designed dual polarized antenna element with $2\times 2$ , $4\times 4$ and $8\times 8$ massive MIMO antenna configuration radiation patterns are deployed in selected geographical situation for detailed radio network planning using FEKO-WinProp platform. Knife edge diffraction, extended walfisch-ikegami and dominant path wave propagation models are implemented with designed MIMO antenna configurations. Modulation schemes of QPSK and QAM with corresponding data rates and throughput for all propagation models are presented. The signal strength and quality reflecting parameters reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), and signal to noise plus interference ratio (SNIR) are also evaluated for each model. From the simulation results dominant path model provides data rate and throughput of 3.827, 995 MBit/s and 3.577, 930.1 MBit/s for single stream of data in uplink and downlink respectively. The maximum data rate of 1.37 GBits/s is achieved for deployed base stations with $8\times 8$ massive MIMO antenna configuration effectively covering the entire geographical site. © 2013 IEEE.Item ANN Model to Predict Joint Stiffness of White-topped Pavements Using Falling Weight Deflectometer (FWD) Data(Springer, 2023) Bellary, A.; Suresha, S.N.The performance of white-topping pavements depends mainly on the functionality of joints. The functionality of joints is measured in terms of its load transfer efficiency (LTE). Falling weight deflectometer (FWD) device is most commonly used to evaluate the performance of joints in the field. Joint stiffness is used as an input parameter in the finite element (FE) based software to compute the LTE. In the present study, an improvement to the existing analytical model is presented that can be used to compute the joint stiffness of white-topping pavements directly from the FWD deflection data. Further, ANN models have been developed and compared for the proposed and previously available analytical models in the literature. The joint stiffness calculated from the ANN model developed from the proposed analytical model is used as an input parameter in FE model and LTE is compared with the field studies. It is concluded that the proposed ANN model can predict the joint stiffness of white-topping pavement accurately and in addition to that, it will also reduce the computation time and cost. © 2021, The Author(s), under exclusive licence to Chinese Society of Pavement Engineering.Item Small-scale laboratory tests for quantifying aggregate interlocking in short-panelled concrete pavements(Taylor and Francis Ltd., 2024) Bellary, A.; Suresha, S.N.In the present study, a simple and reliabe small-scale laboratory test to assess the performance of aggregate interlocked joints in short-panelled concrete pavements in terms of LTE is proposed. In the proposed test method, conventional standard flexural strength test beam specimens (100×100× 500mm) are used for understanding the performance of aggregate interlocking of PQC mix specimens prepared using coarse aggregates of different NMAS and with addition of both micro and macro fibers. The test setup is also modelled in ANSYS FE software. The experimentally obtained LTE is compared with the LTE obtained from the FE model. The field FWD test is conducted for validation. The relative movement is determined from FWD test, and corresponding LTE is determined using the LTE and RM relationship obtained from experimental results using the proposed test apparatus. There exists good linear fit between the LTE determined using proposed test and field FWD test results. © 2024 Informa UK Limited, trading as Taylor & Francis Group.