Faculty Publications
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Item Experimental study on linear displacement measurement sensor using RGB color variation technique with PID controller(Institute of Electrical and Electronics Engineers Inc., 2017) Murthy, A.; Rao, S.S.; Herbert, M.A.; Karanth P, P.This study is based on experimental approach to linear displacement measurement using RGB color coding algorithm. This system is based on the auto-calibration procedure which can be implemented in a circuit, based on the temporal changes in the intensity of light, with the help of a light dependent resistor (LDR). The system consists of two LDRs and an LED placed on one side and an RGB color coded reflective paper on the opposite side. PIC microcontroller is used for powering the LED, processing of data for feedback control and to display the output on an LCD. LDR1 reading is used for displaying the relative linear distance, by mapping the voltage as a function of distance. This reading is used as a feedback to a PID controller to correct for the deviation in the measurement. Extensive experimental observations are conducted to analyze the reliability of the results in accordance to the wavelength of light reflected, the signal voltage and power output of the system. Investigation of the optimum positioning of the LED and the reflective RGB color coded paper is performed by repeatability analysis and hysteresis effects. Furthermore, the efficiency of the system is increased by implementing a PID controller upon investigating the different controller design, viz. P, PI and PID. A high resolution of 0.1 [mm] is obtained for such a simple and economical system, thereby making it highly efficient, in both minute measurements as well as over the entire bandwidth range of the visible light spectrum. © 2017 IEEE.Item Assessment of Pushover Response Parameters Using Response Surface Methodology(Springer Science and Business Media Deutschland GmbH, 2021) Panandikar, N.; Babu Narayan, K.S.B.Pushover analysis is a non-linear static method used for the seismic assessment of structures. The simplicity, efficiency in modelling and less computational time make this method popular. Lot of researchers has worked on conventional pushover analysis and after knowing deficiencies of the method have made efforts to improve it. From the literature, it is evident that actual experimental test results carried out so as to verify the analytically obtained pushover results are hardly available. Stress–strain models adopted for modelling of concrete and reinforcement greatly influences both the ultimate load and ultimate displacement for the structure under pushover loads. This paper focuses on assessment of pushover response parameters using response surface methodology (RSM). A three-storied RCC framed structure is tested and the experimental pushover results are available. Uncertain parameters considered include the concrete strength, steel strength, reinforcement cover and hinge location, which are randomly generated by performing stochastic analysis and their effect on responses, which include base shear and displacement is studied. Using Monte Carlo simulation in Sap-2000 design matrix is generated. Modelling and analysis of response parameters are carried out using RSM so as to obtain the characteristics of the pushover curve. The effect of material strength variation, hinge locations and hinge lengths, geometric modelling have been studied, incorporating confined model for concrete. The coefficients and equations that can be used to predict the responses are carried out by performing multiple regression analysis. The validation results demonstrated that the confined model is better than the unconfined. © 2021, Springer Nature Singapore Pte Ltd.Item Response Analysis of Berthing Structure with Soil–Structure Interaction(Springer Science and Business Media Deutschland GmbH, 2022) Shettigar, S.; Jayalekshmi, B.R.; Venkataramana, K.The berthing structures including piles and diaphragm walls are supported on soft marine soils. The soft soils under severe loading are likely to undergo vertical and lateral movement. The anchored diaphragm wall is provided to support the open berth structure against backfill. In this paper, finite element analysis of berthing structure has been carried out using a finite element program ANSYS APDL. The soil strata is modelled as 3D continuum. The response analysis of diaphragm wall for different pretension forces in anchor rod has been carried out. The variation in displacement, shear force and bending moment along the depth of wall is plotted. The result is compared with the case without considering soil–structure interaction. The optimum value of pretension force is obtained as 1050 kN which effectively reduced the deflection of diaphragm wall. The percentage increase in maximum lateral displacement, shear force and bending moment of wall without considering soil–structure interaction effect was found to be 25.265%, 52.523% and 892.944%, respectively. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Assessment of Structural Damage Due to Blasting in Hydro Power Tunnel(Springer Science and Business Media Deutschland GmbH, 2022) Naveen, G.C.; Sastry, V.R.; Ram Chandar, K.R.Excavation is a major activity in construction of mega underground hydropower project. Successful excavation of access and water conducting tunnels and caverns of different size and shapes by adopting highly economical and efficient method of excavation like drilling and blasting in extreme geological conditions makes the hydropower project a manmade marvel. The national codes which regulates the safety of structures while using explosives are successfully adopted where the tolerable limits for blast induced seismic waves are provided for different type of structures. This paper deals with impact of 9 m(W) and 8 m(H) tunnel blast induced seismic vibrations on the underground and surface concrete structures. The outcome of tunnel blasting with reference to peak particle velocity and related displacements gave a unique results where the seismic wave produced displacements up to 0.04 mm at large underground openings (250 m(L) × 18 m(W) × 59 m(H)) when compared to displacements of 0.016 mm in small openings of 9 m(W) × 8 m(H) with similar peak particle velocity levels of 20 mm/sec. These results subjected the structures which are located in the larger underground openings to lose their strength easily when compared to the structures located in small openings. Further, the structures located in the surface are more vulnerable to get damaged due to higher displacement recordings up to 0.123 mm. Experimental outcome was recorded for various blast design and results were further analyzed to optimize the blast parameters for successful control of blast induced vibration zone within 60 m. The relation between the structure locations where blast induced seismic wave propagates seems to play a key role in influencing on the structural damage, where less influence of peak particle velocity is observed. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Seismic Slope Stability Analysis Using Pseudo-static Approach(Springer Science and Business Media Deutschland GmbH, 2024) Mishra, P.; Venkataramana, K.Ensuring the stability of slopes under the action of an earthquake is always a challenging problem for geotechnical engineers. As earthquake is one of the major factors responsible for the failure of slopes, it becomes necessary to carry out comprehensive research on the stability analysis of slopes subjected to earthquake-induced loads. Many researchers have developed several methods to analyse the stability behaviour of slope, but till now the failure behaviour has not been understood properly because of the complexity of earthquake loading. With the above background, this study presents a numerical analysis, performed in PLAXIS 3D, to investigate the stability of slopes subjected to earthquake-induced loadings using pseudo-static approach. Also, parametric studies have been carried out to better understand the effects of different parameters (soil properties, slope dimensions, earthquake loadings, etc.) on the Factor of Safety (FOS) and displacement of the slope. The stability of a slope is best assessed in terms of its FOS, which is computed by the strength reduction technique. Analyses’ results show that the slope can sustain a maximum displacement of 442.80 mm, while slope height is varied till the failure point keeping all other parameters constant. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Responses of Laterally Loaded Piles in Multi-Layered Sand: Numerical Simulations(Springer Science and Business Media Deutschland GmbH, 2025) Barik, T.; Chaudhary, B.Pile foundations are widely used to support heavy engineering structures by means of load-transferring to deeper soil layers safely. Generally, piles under high-rise buildings, tall chimneys, towers, offshore structures, high retaining walls, etc. are subjected to strong lateral loads. When the soil profile consists of multiple layers, the lateral load responses of piles become complex. They may also affect the lateral load carrying capacity of the pile foundation. Due to this complexity in behaviour, the research has been carried out for the last few decades on it but still the behaviour is not understood completely. Therefore, an attempt has been made to investigate the lateral load carrying capacity of pile foundation in sand under multi-layered conditions by means of Finite Element (FE) Numerical Simulations using PLAXIS 3D. In addition to it, several parameters are studied to better understand the effects of those parameters on the behaviour of pile foundation. It is found from the FE analyses that length and diameter of the pile and soil profile are majorly impactful to the load carrying capacity of the pile while the presence of a water table does not have a significant effect until it reaches the ground level. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.Item Performance of berthing structure under static and dynamic loading(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2014) Yajnheswaran; Rao, S.In berthing structures, lateral forces are caused by impact of berthing ships, pull from mooring ropes and pressure of wind, current, wave and floating ice, seismic force, active earth pressure and differential water pressure, and vertical loads are due to self-weight of the structure and live load. In the analysis considered there is an expansion joint between berthing structure and diaphragm wall. The analysis is carried out using the finite element software PLAXIS 2D with absence of anchor and varying locations of anchor of diaphragm wall. In the case of static loading, the extreme displacement, and bending moment of the diaphragm wall were found to be about 0.07342m,24936.03knm/m respectively in absence of anchor. In the case of seismic loading of the structure, the maximum displacement and bending moment of the diaphragm wall were around0.0749m28263.68knm/m in absence of anchor condition. When anchor is provided the maximum displacement and bending moment were reduced to 0.00642m and 11830knm/m respectively. The variation of bending moment is 13.34% more in dynamic analysis than static analysis. The variation of displacement is 2%more in dynamic analysis than static analysis. © 2014 CAFET-INNOVA TECHNICAL SOCIETY.Item Non-linear analysis of 3D interaction of soil-diaphragm wall structure with different cross-sections(CESER Publications Post Box No. 113 Roorkee 247667, 2016) Yajnheswaran, B.; Rao, S.Diaphragm walls have been used throughout the world to construct deep underground structures, conventionally by using the Reinforced Cement Concrete (RCC).Stiffer walls attracts larger bending moment than flexible walls (Potts & Day, 1991). Research has shown that increase in wall flexibility increases displacement, hence reduction in bending moment. In this paper static analysis of diaphragm wall sections having different stiffness are carried out using PLAXIS 3D software for the load condition existing in deep draft berth of New Mangalore Port, India. The displacement and bending moment are found out for diaphragm wall sections and results are compared with the actual diaphragm wall section having 1.1m thick. For analysis, a single panel diaphragm wall section having 5m length with 2.5m center to center spaced anchors is modelled. Soil properties are considered as per the boreholes data’s obtained from New Mangalore Port. The results are validated with values derived from the design chart. © 2016 by International Journal of Ecology & Development.Item Design, analysis and testing of flexurally amplified piezoactuator based active vibration isolation system for micromilling(Bangladesh University of Engineering and Technology, 2020) Divijesh, P.; Rao, M.; Rao, R.; Ahmed, R.M.; Sushith, K.Vibration is considered to be one of the limiting factors which affects precise measurements and surface finish of various mechanical components. Active Vibration Isolation is one such effective method which reduces the unwanted vibrations in any mechanical systems in a wide range of frequencies. This paper presents the design, analysis and testing of an active vibration isolation system based on Flexurally Amplified Piezo actuators (FAP1 and FAP2). The proposed set up aims at obtaining 180° out of phase displacement signal to the generated displacement signal using FAPs thereby minimising vibrations at the isolation platform. The maximum displacements of FAP1 and FAP2 obtained for 0-150V sinusoidal peak to peak amplitude at 1Hz frequency was found to be 810?m and 780?m respectively. The experimental displacements obtained were compared with simulated displacements using Forward Bouc-Wen hysteresis model and found very well agreed with each other within 1% error. An attempt has been made to estimate the voltage required for obtaining any desired displacement of FAPs using Inverse Bouc-Wen model through Simulink. The experimental displacements for the corresponding estimated voltages were obtained for FAPs. Finally, the proposed set up was tested by actuating both FAP1 and FAP2 separately and simultaneously for 0-150V at 1Hz frequency and was found that the displacements obtained were 180° out of phase thereby minimizing vibrations at the isolation platform. © 2020 Zibeline International Publishing Sdn. Bhd.. All rights reserved.