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 present work relates to the simultaneous determination of concentration and temperature fields from a refractive index field and is motivated by applications in evaporation. Several optical measurement techniques such as schlieren and interferometry can measure the refractive index field, which can then be converted to a density and temperature field for a single component system. The refractive index, however, is dependent on both temperature and concentration for a multi-component system involving combined heat and mass transfer. Hence, either the temperature or concentration field must be known to obtain the other. To circumvent this issue, several methods are evaluated in this study to extract concentration and temperature fields from a refractive index field. The evaluation is performed based on data from a coupled numerical solution of Navier-Stokes, energy and species conservation equations. The refractive index field can be obtained from this computed temperature and concentration field. This refractive index field is then separately used to obtain the combined temperature-concentration field using the method proposed in this work. This method is based on the premise that there is a relationship between temperature and concentration fields which can help to independently calculate both when the refractive index field is known. The temperature and concentration fields obtained using this approach are then compared with the originally computed field and the errors in them are estimated for a wide range of Lewis numbers. From the study, it is concluded that the proposed methods can be used to accurately determine the temperature and concentration fields from a given refractive index field. © 2023 IOP Publishing Ltd.

World University root node

Physica Scripta

Evaluation of temperature and concentration fields from refractive index field for evaporation-induced convective flow

Numerical simulations of fluid-structure interaction problems is an arduous task, specifically for scenarios involving complex moving bodies. Immersed boundary (IB) method which has emerged in recent years as an efficient option for dealing with such hydrodynamic problems, offers a non-body conformal strategy for the smooth exchange of information across interface in moving boundary problems. Amongst several variants of IB with the lattice-Boltzmann (LB) method, the partially saturated cells (PSC) approach has proven to be a promising one, as it offers a unified evolution equation for all the media present in the computational domain. The PSC governing equation features a volume-of-body-based solid-collision operator, which accounts for the accurate implementation of the boundary conditions and dictates a smooth transition of flow variables between the solid and fluid cells. The application of PSC methodology, however, is mostly restricted to hydrodynamic problems till date. In the present study, we propose a novel solid collision operator to simulate incompressible thermal flows with moving bodies. We demonstrate that the PSC solver is as competitive as its existing counterpart and exhibits at least first-order accuracy, while also being Galilean-invariant and capable of accurately implementing the Dirichlet boundary condition. The present investigations further showcases the efficacy and robustness of the new collision operator and PSC approach using a wide spectrum of test cases, encompassing free, forced and mixed convection problems, as well as both stationary and moving boundaries. The proposed algorithm therefore offers a promising and robust computational framework for complex fluid-particle interaction problems with heat transfer. © 2023 Begell House Inc.. All rights reserved.

International Heat Transfer Conference

DEVELOPMENT AND VALIDATION OF A NOVEL SOLID COLLISION OPERATOR IN IB-LB FRAMEWORK FOR SIMULATION OF THERMAL FLOWS

Physics of Fluids

Comment on “Continuum perturbation field in quiescent ambience: Common foundation of flows and acoustics” [Phys. Fluids 35, 056111 (2023)]

Grinding is one of the most widely used subtractive manufacturing processes, used mainly to machine high-strength materials with a high surface finish and close tolerances. This process has covered a unique journey starting from a finishing process to a bulk material removal process. The grinding process has evolved with the adoption of new concepts, technological advancements and market demands. For instance, stone and stone-bed-based grinding in homes has been replaced with compact grinding machines. Similarly, this is the case for industries where new grinding methods and integration with smart controllers are implemented for large production. The application of sustainable technologies, hybrid grinding, micro/nano-grinding, high-speed grinding, textured grinding wheels, 3D printed grinding wheels, the integration of artificial/intelligent systems and precision-shaped grain wheels are some of the key advancements in the grinding process. These recent advancements have entirely revamped the application domain of the grinding process. Furthermore, the incorporation of AI in grinding has enabled the process with simulation tools and self-optimising programs, which is minimising human interference significantly. The current chapter gives a brief introduction to recent advances in the grinding process.

Additive and Subtractive Manufacturing Processes

Grinding and Recent Trends

Haynes 282 is a creep-resistant, γ′ strengthened nickel-based superalloy with excellent weldability. Additive manufacturing, especially laser powder bed fusion (LPBF), of Haynes 282 is being researched for its potential applications in aerospace and power generation sectors. LPBF enables us to achieve desired properties via microstructure control through process parameter optimization. Integrated computational materials engineering (ICME) approach can be used to tune the process parameters to obtain desired microstructure, instead of trial-and-error methods. In this report, ICME framework has been established to simulate microstructural evolution during LPBF and post-processing of Haynes 282. A dimensionless number was used to optimize the process parameters with minimal porosity. Thermal modelling was performed using a semi-analytical model and the obtained thermal data was used to simulate solidification during LPBF. The corresponding cell spacing obtained matched closely with the experimental data. The segregation pattern extracted from the phase-field model was used as input for homogenization simulation. The γ′ precipitate evolution was predicted using Langer–Schwartz theory and Kampmann–Wagner-Numerical (KWN) approach. The predicted values agreed with the experimentally measured values. The room temperature yield strength of as-built samples was comparable and that of heat-treated samples were superior to the aged wrought material.

Journal of Materials Science

ICME framework to simulate microstructure evolution during laser powder bed fusion of Haynes 282 nickel-based superalloy

The title problem is 2-D exterior problem which is solved here by superposing Flamant problems followed by annihilating far-field and boundary tractions using limiting case of Lame’s problem. This method being identical to that used for classical problem of disk under diametral compression (corresponding interior problem), leads to closed-form solution for the exterior problem. Series solution is applicable for distributed loads, which in the limit approaches solution for the title problem. FEM which can model only finite geometries, approximates the infinite domain in the limit. The latter two methods are adopted here for validation of the analytical method by comparison. The analytical method is extended to solve three-point, four-point and n-point loading cases on the circular hole boundary.

Recent Advances in Applied Mechanics

Stress Distribution in Infinitely Long Plate with Circular Hole Loaded by Concentrated Loads

Electric Discharge Hybrid-Machining Processes

Electric Discharge Grinding (EDG)

This study aims to develop a pulse classification algorithm to understand wire electric discharge machining (wire EDM) process stability and performance based on the discharge pulse characteristics. Also, a process data driven failure prediction system is proposed. The wire EDM monitoring system includes high sampling rate differential probes and current probes. The features extracted through pulse train analysis were spark discharge energy, ignition delay time, spark frequency and proportion of various discharges. A pulse discrimination algorithm was proposed, which classifies the discharges into open circuit sparks, arc discharges, short circuit sparks and normal sparks. It was observed that higher proportions of short circuit pulses resulted in inferior part quality. The differences in the pulse cycle during stable and unstable machining were studied based on the extracted features. It was found that the discharge frequency and the proportion of arc and short circuit pulses were extremely high before the wire breakages. An artificial neural network (ANN) model was developed to predict the process responses, like cutting speed and surface roughness, from the process data. Also, an intelligent algorithm was developed based on the extracted in-process data to predict the unstable conditions, leading to machining failures. The accuracy of the algorithm was confirmed to be very high by conducting confirmation tests.

Machining Science and Technology

Performance monitoring and failure prediction system for wire electric discharge machining process through multiple sensor signals

The paper presents structural diagrams of the control system of a robotic system with feedback on the patient’s effort and without it, illustrates the conditions for using each of them; a method is prepared to increase the reliability of data on the applied efforts, associated with the use of strain gauges in the absence of actions of the patient’s motor organs; an example of the patient’s motivation to perform ”correct” movements, ”helping” the mechanism, consisting in changing the speed of movement to form the patient’s feeling that the mechanism moves due to his efforts; a mathematical model of the robotic system was obtained, graphs were constructed demonstrating the accuracy of working out a given trajectory due to the anthropometric parameters of the patient.

2nd International Conference on Robotics and Control Engineering

Control system for a robotic system for rehabilitation of lower limbs with feedback on the patient’s effort

This paper focusses on the development of a Cartesian parallel manipulator (CPM) having multiple limb assembly configurations. An optimal configuration of the 3-PRRR CPM is identified after analysing the interference-free workspace of various limb assembly conditions, where each leg comprises an active prismatic joint followed by three revolute joints. The validation of the link interference detection algorithm is carried out using a virtual prototype. The Euler–Lagrange dynamic modelling of the CPM is validated using one of the well-known multi-body simulation packages namely, ADAMS. The paper proposes a detailed design and performance analyses of a motion controller for the proposed manipulator, based on a finite-time sliding mode scheme. A Graphical User Interface (GUI) is also developed using the MATLAB App Designer, which ensures easier and intuitive synthesis of the CPM. The development of an in-house functional prototype is also presented in this work. © IMechE 2022.