Faculty Publications

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    Blast vibration signal analysis using S-transform
    (Institute of Electrical and Electronics Engineers Inc., 2016) Teja, V.V.S.A.; Chaitanya, S.V.; Akula, U.; Srihari, P.; Sastry, V.R.
    Rock blasting in mines and quarries is an important operation meant for fragmenting and displacing the hard rock mass / strata. The unavoidable environmental effect is the ground vibration, resulting from the wastage of explosive energy. Ground vibrations travelling to far off distances may have effect on the structures. Signal processing techniques play a vital role in analyzing the velocity of ground vibration signals in rock blasting. So far, time-frequency domain is being used for analyzing the ground vibration signals. However, usage of S-Transform, we get frequency dependent resolution of time-frequency domain. It is possible to simultaneously analyze the signal using time, frequency and amplitude values obtained by applying S-transform. A case study is presented in this paper, wherein the S-Transform is applied to the ground vibration velocity signals, which helps in better understanding and analysis of the signal compared to Fourier transform and Wavelet transform techniques. © 2016 IEEE.
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    Frequency and deflection analysis of cenosphere/glass fiber interply hybrid composite cantilever beam
    (American Institute of Physics Inc. subs@aip.org, 2018) Bharath, J.; Joladarashi, S.; Biradar, S.; Kumar, P.N.
    Interply hybrid laminates contain plies made of two or more different composite systems. Hybrid composites have unique features that can be used to meet specified design requirements in a more cost-effective way than nonhybrid composites. They offer many advantages over conventional composites including balanced strength and stiffness, enhanced bending and membrane mechanical properties, balanced thermal distortion stability, improved fatigue/impact resistance, improved fracture toughness and crack arresting properties, reduced weight and cost. In this paper an interply hybrid laminate composite containing Cenosphere reinforced polymer composite core and glass fiber reinforced polymer composite skin is analysied and effect of volume fraction of filler on frequency and load v/s deflection of hybrid composite are studied. Cenosphere reinforced polymer composite has increased specific strength, specific stiffness, specific density, savings in cost and weight. Glass fiber reinforced polymer composite has higher torsional rigidity when compared to metals. These laminate composites are fabricated to meet several structural applications and hence there is a need to study their vibration and deflection properties. Experimental investigation starts with fabrication of interply hybrid composite with cores of cenosphere reinforced epoxy composite volume fractions of CE 15, CE 25, CE15-UC as per ASTM E756-05C, and glasss fiber reinforced epoxy skin, cast product of required dimension by selecting glass fibre of proper thickness which is currently 0.25mm E-glass bidirectional woven glass fabric having density 2500kg/m3, in standard from cast parts of size 230mmX230mmX5mm in an Aluminum mould. Modal analysis of cantilever beam is performed to study the variation of natural frequency with strain gauge and the commercially available Lab-VIEW software and deflection in each of the cases by optical Laser Displacement Measurement Sensor to perform Load versus Deflection Analysis. Young's Modulus values obtained from deflection equation of cantilever beam with different respective load versus deflection values are compared and validated with value obtained using first mode of natural frequency equation of cantilever beam. © 2018 Author(s).
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    Enhancement of Boiling Heat Transfer Using Surface Vibration
    (John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2017) Sathyabhama, A.; Pandiyan, S.P.
    An experimental investigation of the effect of mechanical vibrations of a copper flat circular surface on the pool boiling heat transfer coefficient of water at atmospheric pressure are presented in this paper. A vibration exciter was used to vibrate this copper test surface vertically. Effect of frequency and amplitude of vibration on the boiling heat transfer coefficient was studied. An increase in the heat transfer coefficient was observed at low frequency and amplitudes, at higher amplitude and frequency heat transfer deteriorates. Heat transfer coefficient increases up to 26% with vibration intensity, represented by vibrational Reynolds number. © 2015 Wiley Periodicals, Inc.
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    Free Vibration of Flax Braided Fabric PLA Beam under Edge Compression
    (Taylor and Francis Ltd., 2022) Kanakannavar, S.; Jeyaraj, J.
    The present study focuses on the development of biodegradable composites to replace synthetic polymer-based composites for potential lightweight structural applications in the automobile, aeronautical, marine, and packaging industries. Initially, PLA and NFBF/PLA films are prepared by solution casting, and from these films, composite laminates are prepared by film sequencing and compression (hot-press) molding methods. First, the critical buckling load (Pcr) of composites is analyzed, and then, the influence of compressive load on natural frequency is studied. The critical buckling load-bearing capacity of PLA is enhanced with the reinforcement of NFBF (natural fiber braided yarn fabric). The composite with three layers of NFBF registered the highest critical-buckling load (Pcr) of 374.19 N, and this value is 172.13% high compared to the virgin PLA. Similarly, the natural frequency of the NFBF composites approaches minimum when the applied load is equal to the corresponding Pcr. However, a significant increase in the fundamental frequency is noticed when the applied load is higher than the Pcr. © 2021 Taylor & Francis.
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    Evaluation of the Parametric Effects of Separation of Coal in Vibration Separator Using Plackett–Burman Design of Experiments
    (Springer, 2023) Shanmugam, B.K.S.; Vardhan, H.; Govinda Raj, M.; Kaza, M.; Sah, R.; Hanumanthappa, H.
    Plackett–Burman’s design of experiment (DOE) technique provides a mathematical interrelationship between the output parameter and influential input parameters. The vibration separator performance was evaluated by considering three input variables: moisture, inclination, and frequency. Plackett–Burman DOE consists of a minimum number of 12 experimental trials for obtaining the most influential input parameter of the vibration separator. The output parameter of the vibration separator obtained for each experimental trial was separation efficiency. So, the present work provides the most influential input parameter, which highly controls the separation efficiency of the vibration separator for the separation of coal. The model was validated using the residual analysis. Further, the revalidation of the Plackett–Burman DOE mathematical model for the separation of coal was carried out by comparing the closeness of the experimental cube plot and predicted cube plot. Furthermore, the Pareto chart, normal plot, and ANOVA table were utilized to determine the significant input parameter for obtaining higher efficiency of vibration separator. The main effect plot, interactive plots, and optimization results provide the most optimized input parameter for obtaining higher efficiency of coal separation. So, the present work will provide the most influential parameters using Plackett–Burman DOE for separation of coal in the vibration separator. © 2022, The Indian Institute of Metals - IIM.
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    Effect of piezoelectric ceramic on natural frequency, structural, and thermal properties of additively manufactured PLA/BTO composite structure
    (Elsevier Ltd, 2025) Senthil Murugan, S.S.; Kattimani, S.
    This study investigates the fabrication and characterisation of filaments and 3D-printed samples using polylactic acid (PLA) and PLA/BTO (Barium Titanate) composites via fused deposition additive manufacturing (FDAM). PLA/BTO composite filaments were prepared by blending PLA granules with BTO particles using hot extrusion. Samples were 3D printed under controlled parameters and analyzed for dynamic, thermal, and structural properties. The inclusion of BTO significantly enhanced natural frequency (11 Hz-first peak) and structural rigidity compared to pure PLA (8 Hz-first peak), particularly under cantilever beam configurations. Microstructural analysis via optical and field emission scanning electron microscopy (FESEM) revealed uniform particle dispersion and good layer adhesion in composites with a peak width of 340 ?m. Energy-dispersive X-ray diffraction (EDS) study insisted that the presence of BTO improves functionality with minimal reinforcement with other trace elements. X-ray diffraction (XRD) confirmed increased crystallinity in PLA/BTO samples and improved alignment of the crystalline regions post-FDAM process, while Fourier transform infrared spectroscopy (FTIR) demonstrated molecular interactions between PLA and BTO and highlights the structural modifications in the composite due to the act of BTO reinforcement as nucleating agent. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) highlighted enhanced thermal stability and modified crystallinity due to BTO incorporation. Printed PLA/BTO demonstrates the highest resistance to thermal degradation than pure PLA, with degradation onset at an elevated temperature. Results validate the suitability of PLA/BTO composites for applications requiring tailored dynamic, thermal, and structural properties, emphasizing the FDAM process's potential for advanced material development. © 2025 Elsevier Ltd and Techna Group S.r.l.