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 influence of the suspender on the evaporation of droplets under quiescent atmospheric conditions was studied experimentally using pendant droplets of ethanol (volatile) and water (non-volatile). Conducting and non-conducting suspenders of different materials and configurations (a steel needle, glass needle, steel rod and glass rod) were evaluated. For both liquids, it is observed that the rate of evaporation is higher with steel suspenders. More importantly, for ethanol droplets, there is a difference in the evaporation rates between the needle and rod configurations of the same material. Thus, it is shown for the ethanol droplet that the configuration (needle versus solid rod) also plays a role in the evaporation process, apart from the material. The water droplet does not show this dependence. Visualization of internal flow and heat transfer calculations explain this observation. The results will be useful in choosing an appropriate suspender while using the pendant droplet method for studying complex interactions in an evaporating droplet. © 2019 Elsevier Masson SAS

World University root node

International Journal of Thermal Sciences

Influence of the suspender in evaporating pendant droplets

Scratch tests are useful techniques to gain insight into the material removal mechanism of abrasive machining processes. In most of the scratch tests, uncut chip thickness value is either constant or varies from zero to maximum. However, in abrasive machining processes, uncut chip thickness value ranges from either zero to maximum or vice versa. Moreover, regular scratch tests are conducted at very low speeds, in which either the indenter or the workpiece is stationary. Because of these limitations, the knowledge obtained from the existing scratch test results is not valid for most of the abrasive processes. Hence, in this paper, the influence of chip thickness variation, speed ratio, and depth of cut on the pile-up behaviour of AISI 1015 steel and 2017A-T4 aluminium alloy surfaces were investigated. The workpiece having the comparable thermal diffusivity value with the grit has shown a significant difference in its pile-up behaviour. Through a better understanding of chip thickness influence on pile-up ratio, a mathematical model was developed for kinematic simulations. Using the developed model, kinematic simulations were done to visualise the scratch surface topography and material pile-up by considering the grit trajectory path and chip thickness variation. Finally, simulated surfaces were compared with the experimental results to show the proposed method applicability. © 2019, Springer-Verlag London Ltd., part of Springer Nature.

Fulltext

International Journal of Advanced Manufacturing Technology

Experimental investigations and kinematic simulation of single grit scratched surfaces considering pile-up behaviour: grinding perspective

This article presents a method to characterize electroless plated micro grinding tools using an optical measuring device. Abbott Firestone curve characteristics, such as height distribution, void volume, and material volume obtained from topography measurements, were used to define “volume ratio.” This parameter distinguishes the micro grinding tools according to their planar grit density. As a result, micro grinding tools can be classified in a manner similar to conventional grinding wheels. © 2019 Elsevier Ltd

Optics and Lasers in Engineering

Characterization of micro grinding tools using optical profilometry

The present work focusses on improving the surface wear resistance of commerical pure copper by reinforcing tungsten particles through friction stir processing. Particularly this work adopts Taguchi’s experimental design to achieve minimum wear rate for Copper-Tungsten surface composite by optimizing the process parameters. The rotational and traverse speeds of tool and volume fraction of reinforcement (i.e. tungsten) are the chosen parameters for minimizing the wear rate. Taguchi L9 orthogonal array was used to design the experiments. The surfaces of the processed specimens were investigated by optical microscopy for the distribution of tungsten particles and sliding wear behavior was studied by conducting pin-on-disc method. It was observed from the optical micrographs that the reinforcement evenly dispersed in the processed zone. The measured hardness was 85% higher than the base metal for the specimen exhibited minimum wear rate. The effects of all three parameters on wear rate were studied. The minimum wear rate was achieved by using rotational and traverse speeds of tool, 1200rpm and 60mm/min, respectively. The amount of reinforcement required to achieve maximum wear resistance was 10%. Variance analysis showed that amount of reinforcement played a key role in determining the properties than the other parameters. © 2019 Trans Tech Publications Ltd, Switzerland.

Materials Science Forum

Optimization of friction stir processing parameters for the development of cu-w surface composite

This paper addresses a robust motion control design of a planar 1P-2P RP hybrid manipulator for performing the lower limb rehabilitation treatments. The effectiveness and performances of the proposed system along with the motion control scheme is demonstrated using the real-time experiments. Further the robustness and sensitivity of the proposed control scheme is analyzed under different working conditions. In addition, the applicability of the proposed system is demonstrated successfully on an in-house fabricated prototype as a continuous passive sitting type lower limb rehabilitation mechanism in terms of clinical gait pattern generation and the gait-tracking task. © 2018, Springer Nature B.V.

Journal of Intelligent and Robotic Systems: Theory and Applications

Design and Robust Motion Control of a Planar 1P-2P RP Hybrid Manipulator for Lower Limb Rehabilitation Applications

This paper presents a task-space pose decomposition motion control scheme for a mobile manipulator to simplify the complexity of the conventional task-space pose control. The proposed scheme is decomposing the task-space pose vector (positions and orientation of the end effector) into a position vector and an orientation vector. Further the decomposed position vector (end effector position) is controlled through the task-space control and the orientation vector is controlled by using a joint-space control. The efficacy of the proposed control scheme is demonstrated numerically on a planar mobile manipulator (consists of a mobile platform and two link revolute (2R) serial planar manipulator) and the proposed scheme is compared with the conventional task-space pose control scheme. © Springer Nature Singapore Pte Ltd. 2019.

Advances in Intelligent Systems and Computing

Task-space pose decomposition motion control of a mobile manipulator

The proposed design named as the hybrid propulsion underwater robotic vehicle (HPURV)is a novel underwater vehicle with a hybridized propulsion for minimum energy consumption in ocean observations. This development is aimed at the comparison of different types of propulsion techniques in both vertical and horizontal directions of the motion to choose an optimum strategy for propulsion. The horizontal motion is achieved using the bio-inspired method of fish propulsion using caudal fin or a pair of pectoral fins or both. The tail design is made modular such that the caudal fin can be replaced by a conventional miniature thruster to understand the performance characteristics of the vehicle under similar operating conditions. The diving/climbing, pitching and rolling motions are achieved using three different mechanisms for, viz., (1)pitch and dive using pectoral fins, (2)pitch and dive by varying buoyancy of the vehicle and (3)pitch, dive, and roll by using a moving mass and a rolling mass mechanisms, respectively. All these mechanisms are assembled in the same vehicle and controlled independently or using a combination of two or more different mechanisms for the performance comparison of the vehicle in similar operating conditions. This paper also presents a dynamic model of the HPURV and a motion control scheme using a conventional Proportional-Derivative (PD)control technique to track a given complex spatial trajectory. © 2019 Elsevier Ltd

Ocean Engineering

Conceptual design of a hybrid propulsion underwater robotic vehicle with different propulsion systems for ocean observations

Burnishing is a chipless secondary finishing operation which yields excellent surface finish. The present work focuses on multi-response optimization of diamond burnishing on 17-4 precipitation hardenable stainless steel under dry environment by using Taguchi based grey relation analysis (TGRA) to simultaneously minimize surface roughness and maximize surface hardness. The effect of the process parameters such as burnishing speed, burnishing feed and burnishing force on performance characteristics like surface roughness and surface hardness were studied. Taguchi's L9 orthogonal array has been adopted for the experimental design. The optimal burnishing process parameters were found to be burnishing speed of 73 m/min, burnishing feed of 0.048 mm/rev and burnishing force of 150 N. Burnishing feed is the most significant parameter on burnishing performance characteristics. It has been proved that the performance characteristics of a diamond burnishing process have been improved by effective use of this technique. © Published under licence by IOP Publishing Ltd.

IOP Conference Series: Materials Science and Engineering

Analysis of surface hardness and surface roughness in diamond burnishing of 17-4 PH stainless steel

Monolayer nanostructured thin films of TiSiN & TiAlSiN were deposited on WC-Co milling inserts using RF magnetron sputtering for metal cutting. The alloy targets of TiSi (80/20 at%) & TiAlSi (34/56/10 at%) were used for the deposition in an Ar + N atmosphere. The deposition time and parameters are optimized to develop a uniform and homogenous coating. The mechanical and metallurgical properties are characterized to analyze the wear resistance of the coating. The machinability studies on MDN 250 maraging steel is carried out using TiSiN and TiAlSiN coated WC-Co inserts under dry and wet environment. The machining responses such as surface roughness, cutting force, tool wear and tool life are analyzed by varying spindle speed. The results showed that TiAlSiN coating had a higher wear resistance and machining performance compared to the TiSiN coating owing to the high hardness and plasticity index of the coating. © 2020 IOP Publishing Ltd.

Materials Research Express

Characterisation and performance evaluation of TiSiN &amp;tiAlSiN coatings by RF magnetron sputtering deposition during end milling of maraging steel

17-4 precipitation-hardenable (PH) stainless steel is one of the widely used materials in various applications of engineering practices owing to their excellent corrosion resistance and high strength. The components such as automotive body, aerospace compressor blades, turbine blades and molds demand higher load carrying capacity and improved fatigue strength, which is possible to achieve by surface severe plastic deformation. Diamond burnishing process is an appropriate technique to produce such components which improves the surface integrity characteristics of the material. This article presents a comprehensive examination of the surface integrity of cryogenic diamond burnished 17-4 PH stainless steel using a novel diamond burnishing tool. The impact of diamond burnishing control factors on subsurface microhardness, surface roughness, surface hardness, surface topography, residual stress and surface morphology has been analyzed. The optimal control factor setting ensures the least surface roughness of 0.03 µm by the application of one factor at a time approach. Cryogenic diamond burnished surface achieves the exceptional surface finish and the surface hardness in tool-tip of 8 mm and 6 mm, respectively. The maximum surface hardness of 413 HV was attained using 6-mm tool-tip diameter. The subsurface microhardness improvement of 2% and 4% has been observed while using a tool-tip diameter of 6 mm in contrast to 8 mm and 10 mm. Compressive residual stresses have been generated at the top surface layer of the specimen. The attained experimental results prove that cryogenic diamond burnishing can be successfully applied to 17-4 PH stainless steel to enhance its surface integrity characteristics. © 2019, The Brazilian Society of Mechanical Sciences and Engineering.