Browsing by Author "Gangadharan, K.V."

Now showing 1 - 20 of 126

A comparative study on the effectiveness of system parameters in monitoring pre-load loss in bolted joints
(Springer Verlag service@springer.de, 2018) Anginthaya, K.; Kuchibhatla, S.A.R.; Gangadharan, K.V.; Kishan, A.
This article presents the monitoring of bolt loosening in a single bolted lap joint between two steel beams. The bolt loosening is initially studied using system modal parameters for various boundary conditions. Natural frequency and modal damping ratio in lower modes were not found to be reliable. Transmissibility function was seen to have a more reliable trend to identify the state of the joint. An in-house setup was developed to produce loosening in the bolted joint. Testing configuration was optimized by structural analysis. Strain measurements were carried out using Fiber Bragg-grating sensors while sinusoidal load was applied on the test structure. The results have been used to discuss a viable approach to identify the health of, or recognize a loosening trend, in a bolted joint. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.
A novel approach to characterize the magnetic field and frequency dependent dynamic properties of magnetorheological elastomer for torsional loading conditions
(Elsevier B.V., 2020) Shenoy, K.P.; Poojary, U.; Gangadharan, K.V.
Magnetorheological elastomers (MRE) are potential resilient elements to improve the operating frequency range of a vibration isolator. The field-dependent characterization of MRE properties for varying input frequencies under lateral shear conditions has been well researched in past studies. In the present study, a novel approach to assess the magnetic field dependent rheological properties of magnetorheological elastomers under dynamic torsional loading is presented. Field and frequency-dependent properties are estimated from the dynamic blocked transfer stiffness method specified by ISO 10846. Viscoelastic properties represented in-terms of complex torsional stiffness and loss factor are estimated from the Lissajous curves within the linear viscoelastic (LVE) limit. Experiments are performed at a frequency range of 10 Hz–30 Hz under a constant input angular displacement. Magnetic field sensitive characteristics of MRE are evaluated under the field produced by a custom-made electromagnet. The results reveal a strong influence of field dependent variations on the complex stiffness in comparison with the input frequency. Variations observed in the loss factor suggests a dominance of the imaginary part of the complex stiffness on the energy dissipation. The reduced field induced enhancements in the complex stiffness are interpreted from the Magneto-static and structural based numerical simulations using ANSYS 19.1. © 2019 Elsevier B.V.
A novel approach to investigate effect of magnetic field on dynamic properties of natural rubber based isotropic thick magnetorheological elastomers in shear mode
(Central South University of Technology f-ysxb@mail.csut.edu.cn, 2015) Hegde, S.; Kiran, K.; Gangadharan, K.V.
The preparation of natural rubber based isotropic thick magnetorheological elastomers (MRE) was focused on by varying the percentage volume concentration of carbonyl iron powder and developing a test set up to test the dynamic properties. Effect of magnetic field on the damping ratio was studied on the amplification region of the transmissibility curve. The viscoelastic dynamic damping nature of the elastomer was also studied by analyzing the force-displacement hysteresis graphs. The results show that MR effect increases with the increase in magnetic field as well as carbonyl iron powder particle concentration. It is observed that softer matrix material produces more MR effect. A maximum of 125% improvement in the loss factor is observed for the MRE with 25% carbonyl iron volume concentration. FEMM simulation shows that as carbonyl iron particle distribution becomes denser, MR effect is improved. FEMM analysis also reveals that if the distance between the adjacent iron particles are reduced from 20 ?m to 10 ?m, a 40% increase in stored energy is observed. © 2014, Central South University Press and Springer-Verlag Berlin Heidelberg.
A novel method for dynamic characterization of angular displacement-dependent viscoelastic properties of magnetorheological elastomer under torsional loading conditions
(Institute of Physics Publishing helen.craven@iop.org, 2019) Shenoy, S.K.; Gangadharan, K.V.
The dynamic properties of magnetorheological elastomers are predominantly affected by variation in the input displacements. The displacement-dependent characteristics have been extensively studied under lateral shear, but the property variations under torsional shear have not been explored. The present study focuses on developing a novel method to study the influence of angular displacement on the dynamic properties of magnetorheological elastomers under torsional loading conditions. The experimental setup is developed according to the ISO 10846-2 standard to evaluate the variations in the dynamic torsional stiffness and loss factor. Experiments are conducted for input angular displacements ranging from 0.002 to 0.016 rad for an input frequency between 10 and 30 Hz. Results highlight the effectiveness of the developed method in capturing the rheological properties under torsion. Variations in the dynamic torsional stiffness suggest the dominant behaviour of the input angular displacement. The bound rubber theory is used to interpret the angular displacement dependent variations on the torsional stiffness. Further, the effect of input frequency and magnetic field on the dynamic torsional stiffness is also examined. It is also observed that the damping capacity of the MRE is dependent on the angular displacement and the dissipation capacity of the elastomer is evaluated in terms of loss factor. Results indicate a significant contribution of the interfacial damping over the intrinsic and magneto-mechanical hysteresis damping. © 2019 IOP Publishing Ltd.
Active vibration control of a smart cantilever beam at resonance: A comparison between conventional and real time control
(2012) Parameswaran, A.P.; Gangadharan, K.V.
All mechanical systems suffer from undesirable vibrations during their operations. These vibrations are unavoidable as they depend on various factors. However, for efficient operation of the system, they have to be controlled within the specified limits. Light weight, rapid and multi-mode control of the vibrating structure is possible by the use of piezoelectric sensors and actuators coupled with feedback algorithms. In this paper, direct output feedback based active vibration control has been implemented on a smart cantilever beam at its resonant frequency using PZT (Lead Zirconate Titanate) sensors and actuators. The work aims to showcase the performance abilities of the conventional PC based control and a dedicated REAL TIME CONTROL at resonance. The platform used is LABVIEW RT with FPGA hardware and the system performance is compared with the conventional time multiplexed Operating System (Windows 7) where LABVIEW is again used with the appropriate DAQ devices. � 2012 IEEE.
Active vibration control of a smart cantilever beam at resonance: A comparison between conventional and real time control
(2012) Parameswaran, A.P.; Gangadharan, K.V.
All mechanical systems suffer from undesirable vibrations during their operations. These vibrations are unavoidable as they depend on various factors. However, for efficient operation of the system, they have to be controlled within the specified limits. Light weight, rapid and multi-mode control of the vibrating structure is possible by the use of piezoelectric sensors and actuators coupled with feedback algorithms. In this paper, direct output feedback based active vibration control has been implemented on a smart cantilever beam at its resonant frequency using PZT (Lead Zirconate Titanate) sensors and actuators. The work aims to showcase the performance abilities of the conventional PC based control and a dedicated REAL TIME CONTROL at resonance. The platform used is LABVIEW RT with FPGA hardware and the system performance is compared with the conventional time multiplexed Operating System (Windows 7) where LABVIEW is again used with the appropriate DAQ devices. Â© 2012 IEEE.
Active vibration control of a smart cantilever beam on general purpose operating system
(Defense Scientific Information and Documentation Centre, 2013) Parameswaran, A.P.; Pai, A.B.; Tripathi, P.K.; Gangadharan, K.V.
All mechanical systems suffer from undesirable vibrations during their operations. Their occurrence is uncontrollable as it depends on various factors. However, for efficient operation of the system, these vibrations have to be controlled within the specified limits. Light weight, rapid and multi-mode control of the vibrating structure is possible by the use of piezoelectric sensors and actuators and feedback control algorithms. In this paper, direct output feedback based active vibration control has been implemented on a cantilever beam using Lead Zirconate-Titanate (PZT) sensors and actuators. Three PZT patches were used, one as the sensor, one as the exciter providing the forced vibrations and the third acting as the actuator that provides an equal but opposite phase vibration/force signal to that of sensed so as to damp out the vibrations. The designed algorithm is implemented on Lab VIEW 2010 on Windows 7 Platform. © 2013, DESIDOC.
Aileron endurance test rig design based on high fidelity mathematical modeling
(Springer-Verlag Wien michaela.bolli@springer.at, 2017) Prasad, M.; Gangadharan, K.V.
This paper presents a model-based approach to design aileron endurance test rig (ETR). ETR is a dynamic load simulator which simulates aerodynamic load on-ground for verifying and validating the design, performance and stability of aileron actuator. Aileron actuator is a servo-controlled linear hydraulic actuator used to control the movement of ailerons in aircraft. Aileron is one of the primary flight control surfaces which controls roll of the aircraft. In ETR, Aileron actuator acts as unit under test (UUT) while a double-acting linear hydraulic actuator produces a dynamic load with the help of high pressure fluid source and electro-hydraulic servo valve (EHSV). The design of the test rig depends on load and velocity requirements which vary widely over the whole flight envelop and depends on deflection of surface, angle of attack, aircraft speed and altitude. One of the critical factor in designing ETR is to accurately model the interaction between the UUT and load system. This paper presents a simple yet powerful approach of free body diagram to account the power flow between the two systems. Model-based approach allowed to simulate the complete test rig behavior identifying the values of the critical parameters prior to building it. A high fidelity, non-linear mathematical model of aileron ETR is developed, simulated and verified. An appropriate load actuator and its electro-hydraulic servo valve are chosen to meet load and velocity requirements. The minimum rig structure stiffness is determined to ensure the stability of the load control system. A velocity feed-forward-based load controller along with proportional-integral control is implemented and tuned to meet the load control performance satisfactorily. Finally, the developed model is validated against the experimental data from actual test rig. © 2017, Deutsches Zentrum für Luft- und Raumfahrt e.V.
An adoption model describing clinician’s acceptance of automated diagnostic system for tuberculosis
(Springer Verlag service@springer.de, 2016) Panicker, R.O.; Soman, B.; Gangadharan, K.V.; Sobhana, N.V.
Computerised medical diagnosing systems are very important to all healthcare professionals, especially clinicians who help in clinical decision-making in complex situations. The acceptance of automated or computerised medical diagnosing system for Tuberculosis (TB) among clinicians is very essential for its effective implementation and usage. This paper proposes a framework that aims to examine factors that influence clinician’s acceptance and use of computerised TB detection system. An extended Unified Theory of Acceptance and Use of Technology (UTAUT) model is adopted in the healthcare context of a developing country for this purpose. The proposed framework is expected to help researchers and clinicians to assess the uptake of modern technology by health care professionals and the tool could be used in other healthcare contexts also. This paper also reviewed previous research adopting UTAUT model, for identifying the constructs promoting the adoption of technology acceptance in health care context. © 2016, IUPESM and Springer-Verlag Berlin Heidelberg.
AN ECONOMICAL APPROACH TOWARDS BATHYMETRIC MAPPING OF SHALLOW WATER BASINS USING UNMANNED SURFACE VESSEL
(American Society of Mechanical Engineers (ASME), 2022) Shetty, D.; Kotian, R.; Sequeira, S.L.; Pavithra, N.R.; Umesh, P.; Gangadharan, K.V.
In recent years, the use of unmanned vehicles has advanced because of a growing number of civil applications such as firefighting or non-military security work, such as surveillance of pipelines etc. The application of these technologies with decreased cost and size has received attention in both civil and military applications. Recent advances in sensors, modeling and simulation and availability of open-source software and hardware for data integration has created an environment of remotely monitoring that was not possible a few years ago. This paper examines a niche cost-effective, portable Unmanned Surface Vessel that has been designed to capture the bathymetric profile of shallow water basins using single beam echosounder. Bathymetry is the measurement of the depth of water in oceans, rivers, or lakes. Bathymetric maps look a lot like topographic maps, which use lines to show the shape and elevation of land features. Today, echo sounders are used to make bathymetric measurements. Global shallow water bathymetry maps offer critical information to inform activities such as scientific research, environment protection, and marine transportation. Accurate mapping of shallow bathymetry is critical for understanding and characterizing coastal environments providing a foundation for measuring underwater light density, mapping and monitoring and planning marine operations and transportation. Methods for estimating shallow water bathymetry have suffered from a variety of trade-offs and limitations. Conventional methods such as shipborne sounding or airborne LiDAR have limited spatial coverage. The unit described in this paper has been designed and has been trained to acquire data in a predefined set path, minimizing the human intervention and the associated errors. A successful trial run was done for mapping the bed profile of the river basin in India. The vessel has been upskilled for capturing sonar data sets, with water quality parameters and soil samples using an automated auger. The vessel functions using the combined various open-source software and hardware tools for data assimilation, while the captured data sets are real- time transferred using IOT to Ground Controlled Station. The tropical river basin chosen is a part of Netravati River located in Dakshina Kannada District, Karnataka, India. This area is a part of the monsoon belt, and the Netravati riverbed is subjected to heavy sand deposition during a part of the year. The data on the excessive sand deposition is of immense value to the district and state administration. This study has been carried out at a frequency of 30 days and is provided as an input during non- monsoon period for district administration for outlining removal of excessive sand deposition monitoring of water quality in the estuarine ecosystem. The work done is a one-of-a-kind pilot study developed in-house using the recent advances seen in the world of open-source platforms. This paper demonstrates a unique application that is of value to the state administration in decision making and in addition contributes to environmental monitoring of the riverbed. Â© Â© 2022 by ASME.
An experimental investigation on the matrix dependent rheological properties of MRE
(SAGE Publications Ltd, 2024) Poojary, U.R.; Kiran, K.; Hegde, S.; Gangadharan, K.V.
The rheological properties of magnetorheological elastomers are influenced by magnetically sensitive fillers and the elastomer matrix. The ability to respond to an external magnetic field is imparted by the fillers, while the load-bearing capability is determined by the matrix type. In this paper, the effect of matrix material on the properties of magnetorhological elastomer is explored experimentally. Carbonyl iron particle content is varied by 0%, 15% and 25% by volume to produce magnetorheological elastomer samples using natural rubber, silicone rubber and nitrile butadiene rubber matrices. Forced transmissibility test approach was employed to evaluate the field induced variations in the dynamic stiffness and loss factor of magnetorheological elastomers. The dynamic stiffness of nitrile butadiene rubber is the highest, while that of silicone rubber is the lowest. Addition of carbonyl iron particles significantly improves stiffness, although these gains depend on the properties of unfilled matrix. The addition of 25% by volume of carbonyl iron particle increased the dynamic stiffness of a silicone rubber matrix based magnetorheological elastomer by 67.78%, while the similar change in magnetorheological elastomer with nitrile butadiene rubber matrix was 38.58%. The field dependent response of magnetorheological elastomers is governed by the matrix and ferromagnetic filler concentration. These qualities are higher in magnetorheological elastomer with a low initial dynamic stiffness matrix and lower in magnetorheological elastomers with a stiffer matrix. © The Author(s) 2023.
An experimental study to evaluate the warpage and cracking issues in fused deposition modeling
(Pleiades journals, 2019) Suhas, A.; Rajpal, R.; Gangadharan, K.V.; Umesh, U.
Research in 3D printing technology is growing immensely because of the advantage of manufacturing complex shapes in less time as compared to conventional manufacturing processes. However, warpage and cracking are the critical issues in fused deposition modeling technique which results in a reduction in the strength of the component. This paper aims to address the root causes for reducing the warpage and cracking in a 3D printed component. Fused-deposition-modeling-based 3D printer is used in this study to manufacture the samples. The behavior of warpage and cracking in the specimens are studied by altering bed temperature and extrusion width of the filament. The experimental results revealed that printing a component at 100 °C and 0.75 mm extrusion width led to minimum warpage and no crack condition. © Springer Nature Singapore Pte Ltd. 2019.
Analysis of Magneto-rheological Fluid Damper and Linearization of Semi-active Quarter Car Model
(United Scientific Group, 2023) Puneet, N.P.; Kumbhar, S.; Kumar, H.; Gangadharan, K.V.
A vehicle with better suspension always provides extra satisfaction to the passengers. Active and semi-active suspension systems are meant to overcome the narrow comfort of passive suspension. Though active systems are superior in terms of performance, their cost makes it be used only in limited applications. Semi-active systems are the best compromise between active and passive systems. One procedure to achieve ‘semi-activeness’ is the use of magneto-rheological (MR) fluid in the system where the fluid property can be varied with a change in the magnetic field applied. The use of MR fluid in the damper for vehicular applications is presented in this study. The rheological characteristic of MR fluid prepared in-house is analyzed and the MR damper is characterized to understand the dynamic behavior of synthesized MR fluid. Then, the MR damper is represented mathematically using the modified algebraic model and is used in the quarter car model. Two road profiles are chosen for the analysis. Also, this study has attempted to address complexity arriving in the analysis of MR damper due to nonlinear hysteretic force characteristic using linearization toolbox in MATLAB Simulink. © 2023 Puneet et al.
Analysis of MR damper based on finite element approach
(2014) Hemanth, K.; Ganesha, A.; Hemantha, K.; Gangadharan, K.V.
A magneto rheological damper is a damper filled with magneto rheological fluid, which is controlled by a magnetic field. This allows the damping characteristics of the shock absorber to be continuously controlled by varying the force of the electromagnet. This type of shock absorber has several applications, most notably in semi-active vehicle suspensions which may adapt to road conditions, as they are monitored through sensors in the vehicle. This paper presents magnetic saturation analysis of non-parametric model of magnetorheological (MR) damper using ANSYS for improvement of the higher force with optimal current and MATLAB/Simulink simulation for quarter car model equipped with MR damper to conduct dynamic studies of the system using skyhook controller and comparative study for passive and semi-active system. � (2014) Trans Tech Publications, Switzerland.
Analysis of MR damper based on finite element approach
(Trans Tech Publications Ltd ttp@transtec.ch, 2014) Hemanth, K.; Ganesha, A.; Hemantha, K.; Gangadharan, K.V.
A magneto rheological damper is a damper filled with magneto rheological fluid, which is controlled by a magnetic field. This allows the damping characteristics of the shock absorber to be continuously controlled by varying the force of the electromagnet. This type of shock absorber has several applications, most notably in semi-active vehicle suspensions which may adapt to road conditions, as they are monitored through sensors in the vehicle. This paper presents magnetic saturation analysis of non-parametric model of magnetorheological (MR) damper using ANSYS for improvement of the higher force with optimal current and MATLAB/Simulink simulation for quarter car model equipped with MR damper to conduct dynamic studies of the system using skyhook controller and comparative study for passive and semi-active system. Â© (2014) Trans Tech Publications, Switzerland.
Analytical Studies on Ride Quality and Ride Comfort in Chennai Mass Rapid Transit System (MRTS) Railroad Vehicle
(Springer, 2018) Gangadharan, K.V.; Chandramohan, S.
In this paper analytical ride index studies and ISO 2631 based ride comfort analysis of a suburban MRTS railroad vehicle is presented. Track power spectral densities (PSDs) were used as inputs to a finite element (FE) model of the vehicle and track and the acceleration responses were computed using random vibration theory. From these responses, ride quality and ride comfort have been computed at different locations of the vehicle at different speeds in the vertical and lateral directions. © 2017, The Institution of Engineers (India).
Application of vibration analysis and data mining techniques for bearing fault diagnosis in two stroke IC engine gearbox
(American Institute of Physics Inc. subs@aip.org, 2020) Ravikumar, K.N.; Kumar, H.; Gangadharan, K.V.
This paper is about monitoring of ball bearing used in the IC engine gearbox using condition monitoring techniques. Experiments are conducted on two stroke IC engine which is driven by the 3HP DC motor. Vibration signals are acquired from the gearbox with triaxial accelerometer. Ball bearing with good and induced faulty (outer race fault, inner race fault, ball fault, inner and outer race fault) conditions were used in the analysis. Fault diagnosis of the ball bearing has been carried out using data mining (DM) techniques. In DM there are three stages viz.; feature extraction, feature selection and feature classification. For all the conditions of bearing, statistical and empirical mode decomposition (EMD) features are extracted from the vibration signals. Decision tree technique (J48 algorithm) is used in the analysis for selecting significant features from the feature vector. From the chosen features, ball-bearing conditions are classified using random forest algorithm. Results obtained from the different classifiers were compared, and a better classification algorithm with a decision tree will be suggested for condition monitoring of the rotating components. Â© 2020 Author(s).
Automated low-temperature resistivity measurement setup: Design and fabrication
(Elsevier Ltd, 2021) Saw, A.K.; Channagoudra, G.; Pethker, T.; Gangadharan, K.V.; Dayal, V.
In this paper we present, the design and working of the automated low-temperature four-probe DC electrical resistivity measurement setup developed in-house. This setup measures the resistance/resistivity in the temperature range 300 K to 80 K. The overall arrangement comprises a low-temperature four-probe sample holder, Lakeshore 335 Temperature controller, Keithley Delta mode 6221 AC/DC source, 2182A Nano-voltmeter, and a vacuum system. For the measurement of sample temperature Pt-100 sensor is employed. The IEEE-488.2 card and GPIB cables link the mentioned instruments to the computer. The licenced Lab-VIEW 2018 software is employed to build the control programme. The established setup can measure the resistance of both bulk and thin-film samples, making it versatile. A test measurement on well-characterized ceramic Pr0.67Sr0.33MnO3perovskite oxide synthesized using a solid-state route has been carried out in the newly installed setup. The data acquired from the installed setup and beforehand resistance measurement carried out in-house low-temperature resistance measurement setup at UGC-DAE-Consortium for scientific research, Indore conceded a precision for both temperature and resistance. Â© 2021 Elsevier Ltd. All rights reserved.
Ball bearing fault diagnosis based on vibration signals of two stroke ic engine using continuous wavelet transform
(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2020) Ravikumar, K.N.; Madhusudana, C.K.; Kumar, H.; Gangadharan, K.V.
Ball bearings are used in the different critical fields of engineering applications such as IC engine, centrifugal pump and fans. In IC engine, the ball bearing is one of the critical components and it takes various types of dynamic loads and stresses. Condition monitoring of such ball bearing is very significant to avoid the catastrophic failure of rotating components in IC Engine. This article describes the fault detection of roller ball bearing of an IC engine gearbox with the use of signal processing technique such as spectrum analysis and Continuous Wavelet Transform (CWT) analysis. Vibration signals of IC engine are used to identify the fault in the ball bearing and to detect the healthy and fault bearing conditions. Â© Springer Nature Singapore Pte Ltd 2020.
Bending and free vibration analysis of foam-filled truss core sandwich panel
(SAGE Publications Ltd info@sagepub.co.uk, 2018) Arunkumar, M.P.; Jeyaraj, P.; Gangadharan, K.V.
This paper presents the studies carried out on bending and free vibration behavior of truss core sandwich panel filled with foam typically used in aerospace applications. Equivalent stiffness properties for foam-filled truss core sandwich panel are derived by idealizing 3D foam-filled sandwich panel to an equivalent 2D orthotropic thick plate continuum. The accuracy of the derived elastic property is ensured by the numerical comparison of free vibration response of 3D and its equivalent 2D finite element model. The derived stiffness constants were used in closed form solution to evaluate the maximum deflection of the continuum. The results show that the free vibration and static behavior of the sandwich panel can be enhanced in due consideration to the space constraint by filling foam in the empty space of core. The results also reveal that triangular core foam-filled sandwich panel deflects less compared to other cores. From the free vibration analysis, effect of filling foam is effective in cellular and trapezoidal core. © 2016, © The Author(s) 2016.