Faculty Publications
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Item 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.Item Future applications of carbon nanotube reinforced functionally graded composite materials(2012) Udupa, G.; Rao, S.S.; Gangadharan, K.V.Future applications demand materials having extraordinary mechanical, thermal and chemical properties which must sustain the different environment conditions and in the same time available easily at reasonable prices. The carbon nanotubes(CNT) reinforced functionally graded composite materials(FGCM) is expected to be the new generation material having a wide range of unexplored potential applications in various technological areas such as aerospace, defence, energy, automobile, medicine, structural and chemical industry. They can be used as gas adsorbents, templates, actuators, catalyst supports, probes, chemical sensors, nanopipes, nano-reactors etc. This paper explores in detail the different possibilities of application of CNT reinforced functionally graded composites and manufacturing techniques, which raise the awareness on the promise of nanotechnology and the potential impact on aerospace industry as well as on other areas. © 2012 Pillay Engineering College.Item 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.Item 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. © (2014) Trans Tech Publications, Switzerland.Item Effect of Core Topology on Vibro-acoustic Characteristics of Truss Core Sandwich Panels(Elsevier Ltd, 2016) Arunkumar, M.P.; Jeyaraj, P.; Gangadharan, K.V.; Mailan Chinnapandi, M.C.L.This paper presents numerical simulation studies on effect of core topology on vibro-acoustic behaviour of truss core sandwich panels with metal facings. Free and forced vibration responses of the panels are obtained using finite element method based on the equivalent 2-dimensional models. Sound radiation characteristics of the panel are obtained using Rayleigh integral. It is found that influence of nature of core topology on sound radiation is significant in lower frequencies. It is observed that compared to trapezoidal and rectangular core, triangular core is more suitable for low frequency application and also it radiates less sound compare to trapezoidal and rectangular core. © 2016 The Authors.Item Experimental study on the dynamic properties of magneto-rheological materials(Institute of Physics Publishing helen.craven@iop.org, 2018) Rajpal, R.; Lijesh, K.P.; Kant, M.; Gangadharan, K.V.Magneto-rheological elastomer (MRE), is considered to be a smart material, which transFigure their rheological properties with the external applied magnetic field. Due to this novel property, MREs are extensively employed to control the vibration of a system at resonant frequency. Presently, MREs are integrated in a structure through a layer by layer technique and the bigger drawback of this technology is that, in the presence of high transverse shear stresses, de-lamination occurs which may result in failure of the system. To overcome the aforementioned problem, a novel method is proposed to merge the MREs with Fused Deposition Method (FDM). FDM is used to develop the primary structure with cavities using a FDM compatible material and MRE i.e. secondary material is filled in the cavities. It is postulated that the proposed methodology has the capability of reducing the possibility of de-lamination. Now, to investigate the dynamic performance of the developed structure, an experimental test setup was developed by fixing one end of the beam and supplying the desired magnetic field to the beam using an electromagnet. From the test results, It was concluded that, with the increase in the applied magnetic field, the isolation effect of the structure enhanced and it reduced with the shift of electromagnet from the free end to fixed end of the beam. Further, in the case of MRE, high magnetic field is required for achieving satisfactory performance, which results in increase of the electromagnet weight, in turn making the system bulkier. Therefore, the present work endeavours to replace the MRE with MR Fluid (MRF) in the same primary structure and perform a comparison study between MRE and MRF, for the same applied magnetic field. From the experimental results it was envisaged that the MRF depicted better isolation capability than MRE. © Published under licence by IOP Publishing Ltd.Item Sensor Fusion for Operational Mode Shape Analysis of Multi DoF Systems(Elsevier Ltd, 2018) Rahul, R.; Rajpal, R.; Kuchibhatla, S.A.R.; Gangadharan, K.V.This paper presents an experimental approach to study the dynamic behavior of a multi DOF system by sensor fusion technique. An experimental model is designed and developed to simulate real dynamic problem. Frequency response function (FRF) is obtained by conducting impact hammer test from which natural frequencies of the system are identified. Mode shapes are analyzed using forced vibration test at selected frequency zones. This study illustrates the benefits of using sensor fusion for the study of behavior of complex dynamic systems. © 2018 Elsevier Ltd.Item Parametric Modeling and Real Time Remote Experimentation of a Reconfigurable Coupled Pendulum(Elsevier Ltd, 2018) Rajpal, R.; Kant, M.; Kuchibhatla, S.A.R.; Gangadharan, K.V.This paper presents parametric modeling and real time remote experimentation of a reconfigurable coupled pendulum on a data flow visual programming platform - G Programming. The motivation behind creating the experiment was to make it virtually available for e-learning in the field of vibration analysis & diagnostics. The derived math models replicated the low frequency system dynamics and were used in simulations to highlight inherent system behaviour. Finally, experiment was conducted for various system configuration settings characterized by pre-set discrete lengths of the pendulums. Sensors and actuators used for the experimentation were integrated using LabVIEW. Smartphone and Cross-Platform Communication Toolkit (SCCT) was employed to establish communication between remote user and Master computer. The experiment highlighted bimodal dynamic behaviour of the system in individual and combined modes of vibration through an Internet based remote experimentation platform. © 2018 Elsevier Ltd.Item Experimental investigation of torsional vibration isolation using Magneto Rheological Elastomer(EDP Sciences edps@edpsciences.com, 2018) Shenoy, K.; Singh, A.K.; Sai Aditya Raman, K.; Gangadharan, K.V.Rotating systems suffer from lateral and torsional vibrations which have detrimental effect on the roto-dynamic performance. Many available technologies such as vibration isolators and vibration absorbers deal with the torsional vibrations to a certain extent, however passive isolators and absorbers find less application when the input conditions are dynamic. The present work discusses use of a smart material called as Magneto Rheological Elastomer (MRE), whose properties can be changed based on magnetic field input, as a potential isolator for torsional vibrations under dynamic loading conditions. Carbonyl Iron Particles (CIP) of average size 5 μm were mixed with RTV Silicone rubber to form the MRE. The effect of magnetic field on the system parameters was comprehended under impulse loading conditions using a custom built in-house system. Series arrangement of accelerometers were used to differentiate between the torsional and the bending modes of vibration of the system. Impact hammer tests were carried out on the torsional system to study its response, in the presence and absence of magnetic field. The tests revealed a shift in torsional frequency in the presence of magnetic field which elucidates the ability of MRE to work as a potential vibration isolator for torsional systems. © The Authors, published by EDP Sciences, 2018.Item IoT Based Joystick Controlled Pibot Using Socket Communication(Institute of Electrical and Electronics Engineers Inc., 2018) Radhika, K.A.; Raksha, B.L.; Sujatha, B.R.; Umesh, U.; Gangadharan, K.V.The Internet of things (IoT) and automated frameworks is a key driver of robotic development technology. In current technology, robots are controlled using Smartphone. In our approach Driving Force GT Joystick is used to control the robot wirelessly and which provide precise manual control on a robotic vehicle. Compared to web-controlled or Smartphone controlled Pibot, joystick controlled Pibot is more effective since it provides speed control. In this work, Raspberry Pi is used as a base controller to control robotic car called Pibot to work as real-time system and vehicle operations are controlled remotely at the ground station using USB joystick. The camera on the Pibot is used for live video streaming on a webpage using HTTP server for surveillance. The server-client socket communication (via strong Wi-Fi) is performed for controlling the vehicle in the remote station using python programming. © 2018 IEEE.