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

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Journal of Spacecraft and Rockets

On maximum ballistic coefficient axisymmetric geometries in hypersonic flows

In [1], the authors proposed a charge-conservative numerical framework for simulating electrohydrodynamic two-phase flows where the electric force was discretely treated as the divergence of Maxwell stress tensor because the use of volume-averaged electric force was found to be inaccurate. In this letter, we show that this framework still suffers from inaccuracies, particularly at high permittivity ratios and propose a simple solution that involves reconstruction of electric displacement rather than the electric field. We demonstrate the efficacy of the new remedial approach through simple numerical experiments for different electrical behaviour of the fluids over a range of permittivity ratios. © 2018 Elsevier Inc.

Journal of Computational Physics

Towards an improved conservative approach for simulating electrohydrodynamic two-phase flows using volume-of-fluid

A detailed investigation on the effects of cutting parameters and different cooling environments on machinability of austenitic stainless steel AISI 304 is presented in this study. The need for sustainable manufacturing and better surface quality urged to explore the merits of cryogenic cooling over the other conventional cooling techniques. The end milling experiments were designed based on three parameter and three-level design considering dry, wet, and cryogenic machining environments to have a comparative study. The machinability studies such as surface roughness, tool wear, cutting forces, chip morphology, and chip reduction coefficient were investigated and compared with different machining environments. The machining parameters were optimized using Taguchi-based grey relational analysis. The cryogenic machining had the most influence on milling of AISI 304 steel and resulted in the reduction of cutting forces, surface roughness, and chip reduction coefficient in comparison with the conventional wet and dry machining. © 2018, © 2018 Taylor & Francis.

Materials and Manufacturing Processes

Experimental investigation and optimization of machining parameters for sustainable machining

In this research work, aluminum matrix composite (AMC) plates were welded using friction stir welding (FSW). AMCs contain AA6061 as a base metal with silicon carbide (SiC) and fly ash particles as reinforcements. The FSW process parameters considered in this work were tool rotational speed (revolutions/minute), tool traverse speed (millimeters/minute) and tool tilt angle (degrees). The Taguchi L9 orthogonal array was considered for optimizing the process parameters. Tensile strength and hardness were the two output responses obtained by analyzing joint efficiency and signal/noise ratio. An analysis of variance (Anova) study was conducted to identify the percentage contribution of each process parameter to the output responses. The Anova study concluded that among the three process parameters, tool rotational speed was the most dominant parameter in deciding the tensile strength and hardness of the FSW joints, followed by traverse speed and tool tilt angle. At the end, the results were validated by conducting additional experiments. © 2018 ICE Publishing: All rights reserved.

Emerging Materials Research

Process parameter optimization for FSW of AA6061/SiC/fly ash AMCs using Taguchi technique

Among the materials, composites have unique properties due to less weight and high strength thus meeting the specific requirements for given applications with greater advantages. However, functionally graded materials (FGMs) are a special class of composites. FGMs gained more importance because they have diversified and potential applications in various areas such as automotive, marine, aerospace, medical, etc. FGMs have good mechanical properties and can retain the properties even at high temperatures if design and process is proper. The development of FGMs offers freedom to develop the components with specific properties along different directions with various ratios. The FGMs are fabricated by various methods with various sizes. Hence, in this work, a review of various processing methods for surface coatings and bulk FGMs, FGM applications, and recent research activities on FGMs with more emphasis on additive manufacturing (AM) processes have been done. © 2018 Elsevier Ltd. All rights reserved.

Materials Today: Proceedings

Functionally graded materials and processing techniques: An art of review

Magnetic Resonance Imaging (MRI) is a widely applied non-invasive imaging modality based on non-ionizing radiation which gives excellent images and soft tissue contrast of living tissues. We consider the modified Bloch problem as a model of MRI for flowing spins in an incompressible flow field. After establishing the well-posedness of the corresponding evolution problem, we analyze its spatial semi-discretization using discontinuous Galerkin methods. The high frequency time evolution requires a proper explicit and adaptive temporal discretization. The applicability of the approach is shown for basic examples. © 2017 IMACS

Fulltext

Applied Numerical Mathematics

Numerical simulation of Bloch equations for dynamic magnetic resonance imaging

- A new motion control approach for an underwater robot with four tilting thrusters is proposed and investigated in this paper. The tilting thruster arrangement results in overactuated system which carries out six degree of freedom (DOF) motion with four rotatable thrusters. The dynamic model developed for the robot has a highly nonlinear thrust vector map because of tilting angles. Backstepping control, a non-linear control method is applied to this robot model for continuous tilting motion. The system stability is guaranteed, and the tracking errors asymptotically converge to zero by Lyapunov stability theory. Finally, numerical simulations illustrate the performance of the derived cascaded tracking control technique. © ICROS.

International Conference on Control, Automation and Systems

Design and Implementation of Backstepping Controller for Tilting Thruster Underwater Robot

A multi-layer TiAlN/NbN coated on tungsten carbide insert by physical vapor deposition method (PVD) was selected for studying tool wear performance during end milling of AISI 304 Austenitic stainless steel. Stainless steel AISI 304 belongs to the class of difficult to machine materials, which tends to work harden during machining. The coating has been studied for its micro-mechanical characteristics using SEM/EDS, XRD, 3D confocal microscope & Nano indentation. Characterization results revealed that TiAlN/NbN coatings was well deposited. Dry milling experiments were carried out to evaluate tool life & failure mechanisms of coated tool. It was shown that micro chipping and peeling of coatings were major wear mechanisms observed during dry end milling of AISI 304 using coated inserts. © 2017 Elsevier Ltd. All rights reserved.

Micro-mechanical characterization and wear performance of TiAlN/NbN PVD coated carbide inserts during End milling of AISI 304 Austenitic Stainless Steel

The mechanical properties of hardened AISI 52100 bearing steel such as flexural strength, microhardness and Young’s modulus are considerably influenced by the austenite content retained in the microstructure. A microstructure-sensitive finite element simulation approach is presented which considers the effect of retained austenite to estimate the mechanical properties. The austenite grain size is derived as a function of austenitising temperature and holding time using a modified Arrhenius type equation. The simulation strategy involves division of the two-dimensional domain using triangular elements such that a group of six neighbouring triangular elements represented a hexagonal grain of calculated size. Material inhomogeneity is introduced by enforcing austenite properties to a fraction of the elements equal to the volume percent of retained austenite in the steel. The predictions from the simulation approach for 8% and 20% retained austenite volume fractions matched well with earlier experimental results. © 2015, © IMechE 2015.

Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications

Modelling the mechanical behaviour of heat-treated AISI 52100 bearing steel with retained austenite

The vibration characteristics of the gear system change when gear tooth crack occurs during operating conditions and the system has to be monitored continuously to prevent the damage. A tooth crack model is developed with the mean gear mesh stiffness for external spur gear pair with different crack propagating lengths. Here, potential energy is used to obtain the analytical expression for the mean gear mesh stiffness and mean mesh stiffness with crack is incorporated into the wind turbine gear box and the dynamic analysis is performed with and without crack. The loads acting on the wind turbine drive train considered here are random in nature. The responses of wind turbine drive train in time and frequency domain are used to study the effects of gear tooth crack. The results showed the sidebands at tooth defective frequency in frequency domain and are found to be more sensitive than the gear mesh frequency and its harmonics. Hence the developed crack model is able to predict the presence of gear tooth crack in vibration response. © Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved.

Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics