Faculty Publications
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Item Experimental Modal Analysis Using Impact Hammer Testing with Random Forest-Based Prediction of Magnetorheological Elastomer Dynamics(Institute of Physics, 2025) Shenoy, P.; Kamath, N.; Pawar, K.; Singh, N.; Soundarya; Afnan, S.; Mayya D, S.This study presents a novel integration of impact hammer-based experimental modal analysis with Random Forest Regression (RFR) to rapidly characterise the frequency-domain dynamic behaviour of Carbonyl Iron Particle (CIP)-based Magnetorheological Elastomers (MREs) under varying magnetic fields. Using only applied current and excitation frequency as input features, the RFR model predicts FRF amplitude, phase, and coherence with R2 values exceeding 0.96 across both low-frequency (0-70 Hz) and high-frequency (> 70 Hz) regimes. This hybrid experimental-computational framework significantly reduces the number of repeated tests required, enabling faster parametric studies and paving the way for real-time, AI-enhanced tuning of smart vibration isolation systems. © Published under licence by IOP Publishing Ltd.Item Experimental investigation for vibration attenuation for power tools(American Institute of Physics, 2025) Kamath, N.; Shenoy, P.; Tanappagol, P.S.; Rai, S.K.; Kalluvalappil, G.Construction zones are often buzzing with "chatter"emanating from different machines. The most commonly used machines are hand-held power tools that handle materials such as bricks, concrete, and other masonry-related materials. The labourers are exposed to vibrations from the device during operation for a prolonged period, causing lasting damage to the hand-arm system. Many factors lead to the unpredictable behaviour of the machine, making it difficult to manoeuvre. Increased gripping forces result in the hand-arm system being a better vibration medium. To counteract this effect, smart materials can stabilise the system. Magnetorheological Elastomers are one such material that can solve the problem of stabilising the device as they can adapt to different conditions, providing semi-active isolation for a wide range of frequencies and demonstrating its force-dependent behaviour. A handle made of MRE can be used to replace the conventional handle at the chuck region. This paper presents how the handle behaves in static conditions under the influence of different magnetic fields for an impact hammer test. © 2025 Author(s).Item Growth and morphology of mixed K1-x(NH4)xH2PO4 crystals(Elsevier Ltd, 2010) Shenoy, P.; Bangera, K.V.; Shivakumar, G.K.Mixed crystals of ammonium dihydrogen orthophosphate (ADP) and potassium dihydrogen orthophosphate (KDP), i.e., potassium ammonium dihydrogen phosphate, K1-x(NH4)xH2PO4 have been grown by slow evaporation from the supersaturated solution at an ambient temperature 26 ± 1 °C for ammonium concentration x in the range 0.0 ? x ? 1.0. The morphology changes from tetragonal prism to needles when the concentration of either of the components approaches that of the other. Induction periods were measured for various compositions of mixed crystals of ADP and KDP by the direct vision method. Crystal compositions were determined by flame atomic absorption spectroscopy and also by chemical analysis. Results of the X-ray analysis of the grown crystals are also reported. Maximum size of the grown mixed crystal was around 16 × 10 × 4 mm3. © 2010 Elsevier B.V. All rights reserved.Item Growth and thermal studies on pure ADP, KDP and mixed K 1-x(NH4)xH2PO4 crystals(2010) Shenoy, P.; Bangera, K.V.; Shivakumar, G.K.The investigations on the formation of mixed crystals of ammonium dihydrogen orthophosphate (ADP) and potassium dihydrogen orthophosphate (KDP) i.e. potassium ammonium dihydrogen phosphate, K1-x(NH 4)xH2PO4 have been presented in this paper. Pure and mixed crystals of ADP and KDP have been grown by slow evaporation technique from the supersaturated solution at an ambient temperature 26±1 °C for ammonium concentration x in the range 0.0 ? × ? 1.0 in the case of mixed crystals. Crystal compositions were determined by flame atomic absorption spectroscopy and chemical analysis. The results of the X-ray analysis of the grown crystals are also reported. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study the kinetic process of dehydration and the high temperature phase behaviour. DTA showed the distinct thermal events attributed to dehydration of ADP, KDP and K1-x(NH4)xH2PO4. The results of thermal analysis and chemical analysis are consistent with each other. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Item Theoretical, CFD modelling and experimental investigation of a four-intersecting-vane rotary expander(Elsevier Ltd, 2024) Murthy, A.A.; Krishan, G.; Shenoy, P.; Patil, I.S.Expansion devices significantly impact the performance of the Vapor Compression Refrigeration system and Organic Rankine Cycles. Its improvement has been identified as one of the most crucial parts of future studies. The experiments were carried out using an improved experimental rig with direct coupling of the prototype and the dynamometer. This is done to correct any misalignments caused by external forces. The internal pressure in the working chambers was measured using six pressure transducers at various locations on the expander. A three-dimensional computational fluid dynamics and theoretical model was developed to investigate the effect of losses and inherent physical processes on the prototype. The actual geometry of the stator is taken in the computational fluid dynamics model. Conversely, employing the equation for an irregular stator shape in the theoretical model is difficult. Therefore, a circular stator is considered. The experimental results were used to validate the developed models. The prototype was tested up to 1550 rpm rotating speed, 5 bar (abs) suction pressure, and 1 bar discharge pressure (abs). The computational fluid dynamics and theoretical model results showed that though the volumetric and adiabatic efficiency was generally overpredicted, the trends were very closely predicted. The computational fluid dynamics and the theoretical model could predict the volumetric and adiabatic efficiency with a variance of <19.5% and 14.7%, respectively, for most of the experimental data points. © 2023Item Experimental investigation and ANN analysis of a four-intersecting-vane rotary expander in a micro-scale organic Rankine cycle system(Elsevier Ltd, 2024) Murthy, A.; Naseri, A.; Shenoy, P.; Patil, I.S.Organic Rankine cycles (ORCs) are often used for power generation from low-temperature waste heat. Although the ORC is a well-established technology for medium- to large-scale applications, several issues need to be resolved before it can be widely used in micro-scale applications, including the development of a reliable, low-cost, and efficient expander. A small-scale ORC experimental setup was built using R134 as the working fluid. This paper aims to investigate the performance of a four-intersection-vane rotary expander in a small-scale ORC system. The characteristics include filling factor, isentropic efficiency, and shaft power. The experiments are tested at suction temperatures up to 70 ℃, rotational speeds up to 900 rpm and suction pressures up to 11 bar (abs). The expander demonstrated shaft power of up to 73 W, minimum filling factor of 1.9, and isentropic efficiency of up to 45.6 %. The impacts of lubrication on the performance of the expander are discussed. Besides the experimental work, an Artificial Neural Network (ANN) and Genetic Algorithm (GA) modelling approach was proposed to achieve higher accuracy in mapping the expander's performance. The developed model is evaluated with different parameter settings, train functions and learning rates to increase the prediction accuracy. © 2024 The Author(s)Item Dynamic performance of magnetorheological Elastomer isolators for adaptive torsional vibration control in SDoF Systems: An experimental study(Elsevier B.V., 2025) Shenoy, P.; Murthy, A.A.; Gangadharan, K.V.; Patil, I.S.This paper presents an experimental investigation into the application of Magnetorheological Elastomer (MRE) isolators for torsional vibration isolation in a Single Degree of Freedom (SDoF) system. First, the characteristics have been extensively studied under torsional shear, followed by the derivation of the Parametric modeling for the system parameters using a fractional derivative-based Poynting-Thomson model. After investigating the dynamic properties of Magnetorheological Elastomers, an experimental test was custom-built using a MRE isolator for torsional vibration isolation in a single degree of freedom (SDoF) system. The system's input and output angular displacements were measured using the Serial Arrangement of Accelerometers (SAA) technique, which accurately captures the torsional modes of the system. The reduction in the system's transmissibility ratios, a measure of vibration isolation ability, was used to assess the effectiveness of the MRE isolators. The experimental results show that the system's natural Frequency shifts noticeably in response to different magnetic fields, significantly lowering transmissibility ratios. The impact of damping on the system was also investigated despite some discrepancies in the patterns. Results highlight a reduction in the amplitude transmissibility to 37.36 %. Co-relating to the field-dependent increase in the Stiffness, a frequency shift of 3 Hz is also observed. © 2025 The Authors