Department of Mechanical Engineering

Indian Institute of Technology Palakkad&nbsp;(IIT Palakkad or IIT PKD) is a public autonomous&nbsp;engineering&nbsp;and&nbsp;research&nbsp;institute located in&nbsp;Palakkad,&nbsp;Kerala. It was&nbsp;one of the five new&nbsp;IITs&nbsp;proposed in the&nbsp;2014 Union budget of India. The campus was inaugurated on 3 August 2015. The institute has 94 faculty, 978 students, and 63 non-teaching staffs.

IT Palakkad currently offers four-year Bachelor of Technology (B.Tech) and two years MS programmes in 8 different engineering disciplines including&nbsp;Computer Science, Electrical, Mechanical, Civil among others.

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IIT Palakkad

Difficulties in the grinding of Ti-6Al-4V originate from the three basic properties: poor thermal conductivity, high chemical reactivity and low volume specific heat of the material. Under severe grinding conditions, all these factors together lead to the accelerated wheel loading and redeposition of chips over the work surface. Redeposition and wheel loading have a significant effect on the surface finish, grinding forces, power consumption and wheel life. In this study, water-based Al2O3 nanofluid as metalworking fluid is applied during the surface grinding of Ti-6Al-4V under minimum quantity lubrication mode after dressing the wheel with different dressing overlap ratios. The severity of the redeposition over the work surface was observed by measuring various surface profiles taken perpendicular to the grinding direction at several locations on the ground surface. The nanofluid application was able to prevent redeposition over work surface that became evident from the measured surface finish parameters that results along the grinding direction. Coefficient of friction was estimated On-Machine using the measured forces for different wheel work speed ratios, depth of cut and dressing overlap ratios. The results showed the effectiveness of nanofluid in reducing friction at high material removal rate (i.e. high depth of cut and high speed ratio) conditions when compared to the dry environment. From the measured forces variation with respect to the number of passes, it became evident that, nanofluid application delayed the frequency of wheel loading and grit fracturing cycle, which leads to the increase in the wheel life. © 2016, © IMechE 2016.

World University root node

Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture

Influence of nanofluid application on wheel wear, coefficient of friction and redeposition phenomenon in surface grinding of Ti-6Al-4V

Functionally gradient materials (FGM) are special composites which are having potential applications in aerospace, automotive, marine, electronic, and medical etc. In FGMs, properties changes in direction by gradually varying composition of various elements for a specific requirement. Hence FGMs are used in most of the applications to improve the efficiency and performance. Applications of FGMs are widely explored in many applications however there are few fields yet to be explored. FGM made cylindrical shells are being used in structural applications. The stress distribution of FGM made cylindrical shell for given load conditions have to be analyzed. Hence in this work, modeling and structural analysis have been carried out on a graded cylindrical shell with varying elemental composition from inner surface to the outer surface. Distribution of volume fraction of the elements is calculated using power law for cylindrical shell modeling. Static structural analysis of cylindrical shell which is exposed to internal pressure performed and results are verified with analytical solutions. © 2017 Elsevier Ltd.

Materials Today: Proceedings

Modeling and analysis of functionally graded cylindrical shell

Diamond burnishing is a cold working process, which produces a work hardened and uniform surface by plastic deformation. The aim of the present work is to study the behavior of diamond burnishing on surface integrity of 17-4 precipitation hardenable stainless steel (PH-SS) under cryogenic, minimum quantity lubrication (MQL) and dry environments. Surface modification was achieved by the application of liquid nitrogen during diamond burnishing. The process parameters considered were speed, feed, burnishing depth and number of passes. Surface integrity characteristics such as microhardness and residual stresses were investigated after diamond burnishing under cryogenic, MQL and dry environments. In cryogenic diamond burnishing, the surface integrity characteristics of 17-4 PH stainless steel has been significantly improved when compared to MQL and dry environments. Maximum microhardness of 395 HV, 369 HV, and 357 HV respectively was observed under cryogenic, MQL and dry environment. The maximum residual stress of -352 MPa, -282 MPa and -195 MPa respectively were recorded for cryogenic, MQL and dry environment. © 2018 Elsevier Ltd. All rights reserved.

Effect of cryogenic diamond burnishing on residual stress and microhardness of 17-4 PH stainless steel

Aluminum matrix composite (AMCs) constitute a new class of light weight and high strength materials which have widespread applications in almost all engineering sectors. But the cost of AMCs is the only barrier to increase their applications still. Hence there is a huge demand for the composites containing low cost reinforcement with less weight, keeping this in mind, in the present work, Friction stir welding (FSW) of AA6061/SiC/fly ash was carried out successfully. Microstructural study on the welded specimens was performed using optical microscopy (OM) and scanning electron microscopy (SEM). Results indicate that fly ash particles were uniformly distributed in the weld nugget area because of the stirring action of the FSW tool also promoted the grain refinement of the matrix material with complete elimination of clusters present in matrix material which resulting in sound welds without any defects for AA6061/SiC/fly ash composites. 82% of joint efficiency is obtained for selected AMCs. Transverse tensile test results showed that all welds fractured in HAZ. © 2018 Author(s).

AIP Conference Proceedings

Study on microstructure and tensile properties of fly ash AMCs welded by FSW

Modal analysis of non-rotating structures using wavelet transforms is well established area of research. However, advantages offered by wavelet transforms have not been explored to identify modal parameters of rotating structures. In this study the wavelet based method for estimating speed dependent damping and natural frequencies of a Multi Degree of Freedom (MDOF) rotor bearing systems is presented. Hilbert transform based method to estimate the modal properties is used to validate the wavelet based analysis. The filtering property of wavelet transform is explored to identify the modal parameters corresponding to individual modes of the rotor. A finite element model based simulated results have been presented along with experimental results on a test rotor to illustrate the proposed method. It is observed that for the rotor on fluid film bearings the damping ratio decreased with respect to the excitation frequency. And, for the rotor on rolling element bearings the damping remained nearly constant. © 2018 Elsevier Ltd

Measurement: Journal of the International Measurement Confederation

Wavelet transform based estimation of modal parameters of rotors during operation

Radial growth predictions of rotating labyrinth seals are conventionally obtained from one-dimensional analytical models. However, these predictions quantitatively differ within themselves by about 5-500%. Simulations using three-dimensional finite element method (FEM) are carried out in this paper for a typical labyrinth seal, subjected to high rotational speed and temperature, for a range of radius-to-length ratio of the rotor. Taking the predicted values by FEM as reference, four analytical models are assessed and their errors are quantified. These errors are found to be independent of rotational speed and temperature but significantly vary with the radius-to-length ratio of the rotor. Based on this finding, simple analytical models, together with correction factor charts, are suggested. © 2018 Walter de Gruyter GmbH, Berlin/Boston.

International Journal of Turbo and Jet Engines

Assessment of Analytical Predictions for Radial Growth of Rotating Labyrinth Seals

This paper studies the dynamic analysis and characterization of two-stage planetary gear transmission system for wind turbine drive train under random loads. Rigid multi body dynamics with discrete flexibility is used for modeling the wind turbine drive train. Variable gear mesh stiffness, bearings and shaft stiffness are accounted in this model. The derivation of the system governing equation by Lagrange approach requires the formulation of kinetic and potential energies. The coupled torsional and bending model of 22 degrees of freedom is solved for vibration responses in time domain using Newmark time algorithm. Applying the Fast Fourier Transformation (FFT) on a time signal, vibration responses in frequency domain are obtained and further studied for wind turbine drive train characteristics. To identify the wind characteristics at low frequencies, wavelet decomposition is used. © 2018 Author(s).

Dynamic analysis and characterization of two stage epicyclic gear box in wind turbine drive train

This work develops an inverse methodology to jointly estimate the thermal and mass diffusivities of a solute-solvent system. An inverse parameter estimation framework using a combination of evolutionary simulation and optimization algorithms namely Artificial Neural Network (ANN) and Genetic Algorithm (GA) is discussed. The direct problem is first solved by assuming thermal and mass diffusivities as constants and then as functions of temperature and concentration. Synthetic experimental data is generated by sprinkling noise sampled from three probability distributions namely Gaussian, Uniform and Logistic on the data obtained from direct numerical simulations carried out using prescribed values of diffusivities. This data is then fed into the inverse framework to estimate the parameters of interest and systematically quantify the associated uncertainties. In case of diffusivities dependent on temperature and concentration both, the higher order parameters are also jointly retrieved and associated uncertainties are quantified. Three sets of experiments namely diffusion of heat in water due to applied temperature difference, isothermal diffusion of salt solution in fresh water and diffusion of salt solution in fresh water along with simultaneous counter current heat diffusion are performed. The time evolving temperature and concentration fields are captured in the form of an interferogram using a Mach-Zehnder interferometer illuminated by a monochromatic laser source (Helium-Neon laser, λ = 632.8 nm). The temperature and concentration data thus obtained is used to estimate the thermal and mass diffusivities of the solute-solvent system using the inverse framework. The results obtained are compared against literature to validate the proposed parameter estimation methodology. © 2017 Elsevier Masson SAS

International Journal of Thermal Sciences

Joint estimation of thermal and mass diffusivities of a solute-solvent system using ANN-GA based inverse framework

This study presents a methodology to estimate the in-plane thermal conductivity of copper clad board used in electronic applications. Experiments are performed in vacuum environment and an inverse heat conduction problem (IHCP) is solved employing artificial neural networks to estimate the in-plane thermal conductivity. A comparison of estimates of thermal conductivity as obtained by solving the inverse problem using back propagation artificial neural networks trained using two algorithms namely Levenberg-Marquardt and Scaled Conjugate Gradient are presented. © Published under licence by IOP Publishing Ltd.

Fulltext

IOP Conference Series: Materials Science and Engineering

Estimation of in-plane thermal conductivity of copper clad board by inverse analysis using artificial neural networks

A coupled experimental and theoretical study is reported here on friction hydro-pillar processing of AISI 4140 steel, which is a novel solid-state joining technique to repair and fill crack holes in thick-walled components by an external stud. The stud is rotated and forced to fill a crack hole by plastic flow. During the process, frictional heating occurs along the interface of the stud and the wall of crack hole leading to thermal softening of the stud that eases its plastic deformation. The effect of the stud force, its rotational speed and the total processing time on the rate of heat generation and resulting transient temperature field is therefore examined to correlate the processing variables with the joint structure and properties in a systematic and quantitative manner, which is currently scarce in the published literature. The results show that a gentler stud force rate and greater processing time can promote proper filling of the crack hole and facilitate a defect-free joint between the stud and original component. © The Minerals, Metals & Materials Society and ASM International 2018.