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

We consider steady, fully-developed flows of deformable, inelastic grains driven by gravity between identical bumpy walls. Using constitutive relations from extended kinetic theory (EKT) for the erodible bed near the centreline and the collisional flow between the surfaces of the bed and the walls, we calculate the fields of mean velocity, fluctuation velocity and solid volume fraction across the chute. We consider both situations in which the solid volume fraction at and near the centreline is high enough to form a bed and when it is not. We compare results predicted by EKT with recent discrete element simulations results, and obtain very good agreement.

World University root node

Journal of Fluid Mechanics

Extended kinetic theory for granular flow in a vertical chute

We investigate arbitrarily large indentations of beams in two dimensions by a frictionless and rigid cylindrical punch whose axis is perpendicular to the plane of the beam. The beam is modeled as a geometrically exact beam that admits large displacements and rotations. Absence of both friction and inter-penetration between the contacting surfaces allows the normal contact pressure and the separation between the surfaces to be related by the Karush–Kuhn–Tucker (KKT) conditions. This is then implemented in a nonlinear finite element framework through both penalty and augmented lagrangian methods. We solve for the contact domain and the forces and moments acting within it, and relate them to the total applied force and the extent of indentation. We report results for several punch radii and beam thicknesses and consider both pinned and clamped beams. In this, we discuss the importance of nonlinear effects such as wrapping of the beam around the punch and the stiffening of the beam due to axial stretch. We demonstrate the importance of utilizing a nonlinear beam formulation by comparing our results with the predictions of theories predicated on small deformations. For example, while the latter claim loss of contact with the beam in the vicinity of the punch’s apex as the indentation proceeds, we find that the punch and the beam remain in contact. &nbsp;

International Journal of Solids and Structures

Indentation of geometrically exact beams

The grain size of materials is significantly reduced by dynamic recrystallization (DRX), which improves the properties and performance of the materials, and it helps to extend the applications further. DRX behavior of the composite materials is greatly affected by the addition of reinforcement to the matrix due to the heterogeneous temperature of the composite. Therefore, the present investigation aims to study the DRX behavior of hot upset sintered Al-B4C composite with various percentages of B4C content (2, 4 and 6 wt.% of B4C) with 90% of initial relative density. Hot upset tests were performed for various temperatures (300-500 °C) and strain rates (0.1-0.3 s−1). The DRX grain size was significantly altered not only with deformation conditions but also with the addition of reinforcement in the matrix. The fracture surface of the sintered composite was analyzed for various compositions. Ductile fracture is observed in the 2 and 4 wt.%B4C content, and ductile and brittle fractures were observed in the 6 wt.%B4C composites. DRX models were established between grain size and deformation conditions for various compositions to predict the grain size, and the developed models were validated. The measured and calculated DRX grain size absolute error and mean absolute error were not exceeding 8.9 and 7.7%, respectively.

Journal of Materials Engineering and Performance

Influence of Reinforcement Particles on Dynamically Recrystallized Grain of Hot Upset Sintered Al-B4C Composites

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

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)

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 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.