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

In this work, the governing equation of asymmetric continuous shaft in inertial frame of reference is studied. In particular, determination of the parameter ranges for the stability or instability of the shaft response is the focus of the present work. The governing equations are a fourth-order coupled partial differential equations containing time dependent coefficients. The equations are non-dimensionalized in terms of two parameters related to the average moment of inertia and the difference of moments of inertia about the principal axes. Using the latter as the asymptotic parameter and employing modal superposition, a formal methodology based on perturbation methods is developed to ascertain the stability and instability characteristics. The methodology is applicable to shafts subjected to some of the classical boundary conditions viz. simply supported, cantilever, and fixed–fixed. Similar stability curves are obtained for each mode for these different boundary conditions. The novel non-dimensionalization scheme chosen leads to the stability boundaries as well as the loci of varying speeds to be in the form of straight lines. The intersection of these lines determine the stable and unstable speed ranges of different asymmetric shafts. The results are generalized for different material and geometric properties of the shaft. © 2016 Elsevier Ltd

World University root node

Journal of Sound and Vibration

Instability of asymmetric continuous shaft system

A Study on the Compound EDM-arcing and Deep Hole Drilling of Inconel 718

Cryogenics

Performance of two mixed refrigerant processes providing refrigeration at 70 K

The paper discusses the development of a linkage based amphibian legged robot for exploration and surveillance tasks. The proposed system can walk on both ground and water surfaces. The proposed system has two major mechanisms for its motion namely a planar eight bar Jansen mechanism as a leg and an Ackermann steering mechanism as for turning. The performance of the proposed mechanisms is verified in terms of motion, force (motion/walking) and structural aspects. The effectiveness and performance of the system is demonstrated by using an in-house fabricated prototype for different working conditions. The Jansen legged mechanism is redesigned in order to improve the drag force during walking on the water surface. © Springer Nature Singapore Pte Ltd. 2016.

Communications in Computer and Information Science

Development of an amphibian legged robot based on jansen mechanism for exploration tasks

A new flux splitting scheme based on wave-particle behaviour is developed for one-dimensional ideal magnetohydrodynamics. We exploit the idea that while ideal magnetohydrodynamics equations are non-convex with non-homogeneous fluxes as opposed to their hydrodynamic counterparts, they exhibit an overall wave-like structure. The proposed approach splits the flux vector into three distinct parts: the particle-like transport part and the wave-like pressure and magnetic parts, with the latter vanishing for pure hydrodynamics. The pressure part of the fluxes satisfy homogeneity property and the split flux Jacobians are constructed with a provision to regulate the numerical dissipation. The magnetic part of the fluxes however is non-homogeneous and is treated using a central scheme with artificial viscosity. This disparate treatment of the individual components of the total flux vector results in a scheme with a central-upwind character that can be implemented with low computational effort. Referred to as Magneto-acoustic Wave Particle Splitting (MWPS) scheme, it is extended to second-order accuracy by using slope limiters incorporated through the solution-dependent weighted least squares approach for gradient calculations. Several one-dimensional MHD problems are numerically solved to highlight the accuracy, positivity preservation and robustness of the MWPS scheme and comparative studies show that MWPS performs at least as well as the Advection Upstream Splitting Method (AUSM) and even outperforms it for some test cases. © 2016 Elsevier Inc.

Journal of Computational Physics

A novel second-order flux splitting for ideal magnetohydrodynamics

In present era, day by day new engineering materials are forthcoming but among all, the composites, especially epoxy polymer composites have important advantages because of its superior mechanical properties such as high strength to weight ratio, high wear resistance, corrosion resistance, electrical resistance, and etc. It can replace the traditional materials for manufacturing different components with required properties. The major applications of these composites are in electronic industry, automobile industry and aerospace industry. In this work, a glass fibre reinforced polymer (GFRP) composite is fabricated using epoxy polymer Araldite LY556 matrix reinforced with 12 layers of glass fibers and properties such as tensile strength and hardness are measured. Generally, drilling of GFRP composites is difficult unlike traditional materials due to anisotropic nature. Hence, authors made an attempt to carry out the experimental study on drilling of GFRP composites and optimize the parameters based on material removal rate and delamination damage using Taguchi method. © 2016 IEEE.

2016 International Conference on Energy Efficient Technologies for Sustainability, ICEETS 2016

Optimization of drilling parameters of fabricated GFRP composite using Taguchi method

Dynamic analysis of wind turbine drive train subjected to stochastic aerodynamic loads is carried out in the present study. The longitudinal wind speed at the turbine site normally consists of a mean value superimposed with ramp, gust and turbulence components. In the present study, the aerodynamic torque is obtained by considering wind speed parameters of a typical wind turbine site. The dynamic model accounts for time varying gear mesh stiffness, bearing elasticity and torsional shaft stiffness. The dynamic analysis is done with stochastic aerodynamic loads and the vibration responses are obtained in time and frequency domains. It is observed that the entire spectral content of the vibration signals is confined to low frequency region, whereas higher frequencies are hidden. In order to capture the hidden frequency information from vibration signals, the wavelet decomposition technique is used. The dynamic analysis using torque signals is also discussed. The present study shows that, from the internal resistive torque all the characteristic frequencies can be clearly observed. © 2015 Elsevier Ltd.

Mechanism and Machine Theory

Wind turbine drive train dynamic characterization using vibration and torque signals

Al-Zn-Mg alloys are widely used as structural materials due to high strength-to-weight ratio and impact toughness. As fusion welds in these alloys commonly face hot cracking and macro porosity, friction stir welding is increasingly becoming the preferred recourse. We report here a detailed experimental study on friction stir welding of a specific Al-Zn-Mg alloy with its chemical compositions close to AA7039. The effect of tool rotational speed and welding speed on the weld profile, joint microstructure, and mechanical properties is studied extensively. The results show sound weld profiles and joint properties within the selected range of process conditions. Within the selected range of welding conditions, the welds made at a tool rotational speed of 350 rpm and welding speed of 3 mm/s have showed joint structure, tensile, and impact toughness properties fairly close to that of the base material. © 2016, ASM International.

Journal of Materials Engineering and Performance

Friction Stir Welding of a Thick Al-Zn-Mg Alloy Plate

Axis switching in non-circular tube burner flame jets is studied. Experimental data of heat flux is obtained for square and rectangular burners of different aspect ratios: 1, 1.55, 2.1 and 3.73. A three dimensional CFD simulation is carried out to explain the phenomenon of axis switching in premixed flame jets. From the CFD simulations it is observed that the vortices formed near the corner of the tube exit are responsible for the axis switching phenomenon. These vortices control the spreading (in a preferential manner) of the flame jet along the tube axis. This preferential spreading of the flame jet is responsible for switching of contours of heat flux on the impingement plate. Furthermore, for the rectangular burner, elliptical lobes of heat flux distribution on the impingement plate are observed and this is again attributed to vortex structures. © 2016 Elsevier Ltd

Applied Thermal Engineering

Axis switching in impinging premixed methane-air flame jets

This paper proposes a kinematically redundant planar manipulator for lower limb rehabilitation application, having configuration 4PRP. The challenges in the existing mechanisms has been analyzed and a new configuration is proposed. This configuration helps to improve the effective workspace of the lower limb rehabilitation robot. The lower limb rehabilitation systems are used to treat the post stroke patients and limb injured patients by providing rigorous exercises through the motor nerves recovery. This paper shows the advantages of the proposed 4-PRP kinematically redundant planar manipulator over existing 2PRP-2PPR in providing higher effective workspace with same capability in performing lower limb rehabilitation tasks. © Springer Nature Singapore Pte Ltd. 2016.