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

The paper discusses a robotic system (RS) for the rehabilitation of the lower limbs of patients. The system consists of an active parallel 3-PRRR robot and a passive part of the RRRR orthoses. A 3D model of a passive RRRR orthosis’s joint structure was developed, taking into account patients’ fit with different anthropological data. The requirements for the body mass index of patients are formulated to optimize the design parameters. This made it possible to determine the rehabilitation system’s workspace, taking into account the minimum and maximum regulation of the passive orthosis joints based on optimization methods. The simulation results are presented. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

World University root node

Mechanisms and Machine Science

Designing a Robotized System for Rehabilitation Taking into Account Anthropological Data of Patients

This paper focuses its attention on investigating the mechanical design and control aspects of a new autonomous mobile agricultural robot being developed for the purpose of automated harvesting of fruits in plantations. The paper goes from discussing the need of automated harvesting of fruits and the problems involved to conceptualizing the design of such a robot and ends with a brief discussion on the control aspects of the robot. © IMechE 2022.

Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science

Investigation on design and control aspects of a new autonomous mobile agricultural fruit harvesting robot

The current work aims to study the influence of discharge energy and debris accumulation on wire break failure and surface integrity aspects like surface roughness, subsurface hardness, and geometrical errors during the wire EDM of Inconel 718. The responses considered for analysing the geometrical accuracies are flatness error, roundness error and cylindricity error. Four different wire electrodes were considered for the study based on the wire strength and coatings, namely hard zinc coated brass, half-hard zinc coated brass, hard uncoated brass, and half-hard uncoated brass wire electrodes. The geometric accuracy of the machined parts is closely related to the choice of wire electrode. High-tensile strength hard wires were observed to machine the surfaces with maximum accuracy. Also, the zinc coated wires were observed to cut faster compared to the uncoated wire electrodes. The study revealed that there exists a strong influence of discharge energy on the surface integrity of wire electric discharge machined surface. The zinc and copper elemental contamination was minimal for uncoated wire electrodes at lowest discharge energy mode. Wire wear phenomena was analysed for both coated and uncoated wires. Discharge energy had a significant impact on the electrode wear of coated and uncoated wire electrode. © 2022 Informa UK Limited, trading as Taylor & Francis Group.

Advances in Materials and Processing Technologies

Effect of wire material and discharge energy on productivity and surface integrity of WEDM-processed Inconel 718

Machining is a metal removal process in which a large quantity of heat is generated due to interaction of the tool with the workpiece. Suitable cutting fluids are used to remove heat, prevent tool wear, enhancing tool life and reducing workpiece distortion, along with several other merits. However, these are not eco-friendly, and preventive measures should be taken while discarding. Sustainable machining, which includes modifying the existing processes or development of new processes, both aiming to maintain eco-friendly nature, is the way forward. The current chapter aims to comprehensively review dry machining, minimum quality lubrication, and cryogenic machining with their advantages and disadvantages. The status of sustainability in turning, grinding, milling, broaching, and boring has been presented. Importance of surface textured tools has been highlighted. Sustainability in nonconventional machining processes such as electric discharge machining, electrochemical machining, abrasive water jet machining, laser beam machining, and ultrasonic machining is also presented with novel developments. Finally, a summary of future prospects with recent advances is included. © 2023 Elsevier Inc. All rights reserved.

Sustainable Manufacturing Processes

Sustainable manufacturing strategies in machining

Deformation of a droplet from an initial spherical shape to a disk-like structure is common during its secondary breakup. Characterizing this initial deformation is important to develop accurate secondary breakup models. In the present study, the initial droplet deformation until initiation time (where the droplet attains a disk-like structure) was investigated by experiments with a variety of test liquids offering wide ranges of surface tension (0.022–0.71 N/m), viscosity (0.86–3.63 mPa⋅s) and density (788–6900 kg/m3). The test liquids included molten metals along with classical water-like liquids. To characterize the initial droplet deformation until the initiation time, the droplet's displacement, relative velocity, deformation and drag coefficient (CD) were measured. A non-dimensional parameter named the displacement–relative velocity–deformation (DVD) parameter was introduced and a mathematical expression for its temporal evolution, which could be useful for validating simulation results, was obtained. The temporal evolution of the DVD parameter and the droplet's displacement, relative velocity and deformation (in non-dimensional forms) for molten metals were observed to be significantly different from those for the other liquids at similar Weber numbers. A correlation for the non-dimensional droplet deformation at the initiation time is also presented by studying the relationship between an instantaneous Weber number defined at the initiation time (Weini) and the corresponding conventional Weber number (We). It is observed that the temporal evolution of CD until the initiation time for ∼30<We<∼70 (where dual-bag and sheet-thinning breakup modes are observed) is significantly different in comparison to that for ∼10<We<∼30 (where bag and bag-stamen breakup modes are observed). © 2021 Elsevier Ltd

International Journal of Multiphase Flow

Droplet deformation in secondary breakup: Transformation from a sphere to a disk-like structure

In this paper, we study the dynamic behavior of the cylindrical shells subjected to static and time-varying (periodic) radial loading. Flügge-Luré-Byrne shell theory has been used to derive dynamic equations in the form of nonlinear partial differential equations (PDEs). Linearization of PDEs about the steady-state periodic solutions, followed by Galerkin projection, yields a system of ordinary differential equations (ODEs) with time-varying periodic coefficients. Those are similar to the higher-order Mathieu-Hill equations and their stability analyses have been ascertained using Floquet theory. Dynamic instabilities of the cylindrical shells have been presented through stability charts in the plane of forcing parameters, namely, the static component of the pressure, the amplitude and frequency of the fluctuating component of the pressure. Also, possible sub and super harmonic resonances have been explored through the stability charts. Four different boundary conditions, viz., simply supported, clamped–free, pinned–free (axial constraint at the pinned end) and pinned–free (axial constraint at the free end) have been considered in the present analysis. Presented charts can be very useful during the design of the shell structures subjected to static/dynamic loading. © 2022 Elsevier Ltd

Journal of Sound and Vibration

On the stability of thin-walled circular cylindrical shells under static and periodic radial loading

Physics of Fluids

Comment on “Fluid-like representation of Fickian diffusion” [Phys. Fluids 34, 011701 (2022)]

Cellular membranes are highly dynamic in shape. They can rapidly and precisely regulate their shape to perform various cellular functions. The protein’s ability to sense membrane curvature is essential in various biological events such as cell signaling and membrane trafficking. As they are bound, these curvature-sensing proteins may also change the local membrane shape by one or more curvature driving mechanisms. Established curvature-sensing/driving mechanisms rely on proteins with specific structural features such as amphipathic helices and intrinsically curved shapes. However, the recent discovery and characterization of many proteins have shattered the protein structure–function paradigm, believing that the protein functions require a unique structural feature. Typically, such structure-independent functions are carried either entirely by intrinsically disordered proteins or hybrid proteins containing disordered regions and structured domains. It is becoming more apparent that disordered proteins and regions can be potent sensors/inducers of membrane curvatures. In this article, we outline the basic features of disordered proteins and regions, the motifs in such proteins that encode the function, mem- brane remodeling by disordered proteins and regions, and assays that may be employed to investigate curvature sensing and generation by ordered/disordered proteins.

Fulltext

Journal of Membrane Biology

Insights into Membrane Curvature Sensing and Membrane Remodeling by Intrinsically Disordered Proteins and Protein Regions

Soot volume fraction predictions through simulations carried out on OpenFOAM® are reported in diffusion flames with ethylene fuel. A single-step global reaction mechanism for gas-phase species with an infinitely fast chemistry assumption is employed. Traditionally soot formation includes inception, nucleation, agglomeration, growth, and oxidation processes, and the individual rates are solved to determine soot levels. However, in the present work, the detailed model is replaced with the soot formation and oxidation rates, defined as analytical functions of mixture fraction and temperature, where the net soot formation rate can be defined as the sum of individual soot formation and oxidation rates. The soot formation/oxidation rates are modelled as surface area-independent processes. The flame is modelled by solving conservation equations for continuity, momentum, total energy, and species mass fractions. Additionally, separate conservation equations are solved to compute the mixture fraction and soot mass fraction consisting of source terms that are identical and account for the mixture fraction consumption/production due to soot. As a consequence, computational time can be reduced drastically. This is a quantitative approach that gives the principal soot formation regions depending on the combination of local mixture fraction and temperature. The implemented model is based on the smoke point height, an empirical method to predict the sooting propensity based on fuel stoichiometry. The model predicts better soot volume fraction in buoyant diffusion flames. It was also observed that the optimal fuel constants to evaluate soot formation rates for different fuels change with fuel stoichiometry. However, soot oxidation strictly occurs in a particular region in the flame; hence, they are independent of fuel. The numerical results are compared with the experimental measurements, showing an excellent agreement for the velocity and temperature. Qualitative agreements are observed for the soot volume fraction predictions. A close agreement was obtained in smoke point prediction for the overventilated flame. An established theory through simulations was also observed, which states that the amount of soot production is proportional to the fuel flow rate. Further validations underscore the predictive capabilities. Model improvements are also reported with better predictions of soot volume fractions through modifications to the model constants based on mixture fraction range. © 2021 American Society of Mechanical Engineers (ASME). All rights reserved.

Proceedings of the ASME Turbo Expo

Analytical formulation-based soot modelling in ethylene laminar jet diffusion flames

The graphical interactive user interface system of a stationary trainer for performing lower-limb rehabilitation tasks is presented in this article. The stationary trainer considered here for the interactive system development is based on a foot-plate operating system. The foot-plate is an end-effector of a parallel Cartesian manipulator. The interactive system primarily designed for the therapeutic tasks associated with passive range of motion (PROM) of the lower limbs. Further, the interactive system concentrated on the hip and knee joint motion therapies which include flexion/extension of knee and hip as well as abduction/adduction of hip. Various clinically suggested motions along with their working nature are designed in the interactive user interface. The suggested interface would generate the system settings (the various system parameters to be fixed during the real-time training) are generated based on the patient's physical parameters such as limb length, patient's weight, height, etc. The interactive simulator of the stationary trainer is demonstrated and verified using computer-based numerical simulations. © Published under licence by IOP Publishing Ltd.