Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Mechanical

The objective of this endeavor is to investigate the influence of graphite particles addition to the Al/SiC composites manufactured by stir casting method. Al/SiC/Gr hybrid metal matrix composites are preferred replacement for single reinforced composites by virtue of strengthened mechanical and tribological properties. A layered SiC/Gr composite material is required in gas turbine combustor can. Al/SiC/Gr composites are required in bearings, and pistons due to selflubrication, low wear rate and less friction. The inclusion of both strong reinforcement like SiC and smooth reinforcement like graphite enhances hardness and wear resistance of aluminium composites. The reinforcement content of graphite was varied from 2.5 to 7.5 wt % in a step of 2.5 wt. The SiC was fixed at 5 wt. % for all the three specimens, and Al6061 was used as matrix base material. The microstructure and EDAX analyses were required for three samples of hybrid metal matrix composites. Vickers hardness and porosity decreases for Al/SiC/Gr hybrid composites when percentage of graphite content increases. A review of surface modification of Al/SiC/Gr was done to find the different materials used for coating hybrid composites. © 2019, Informatics Publishing Limited &amp; Indian Society for Surface Science and Technology. All rights reserved.

School of Mechanical Engineering

Chennai Campus

Journal of Surface Science and Technology

Study on microstructure and EDAX analysis of Al/SiC/Gr hybrid metal matrix composites

Revolutions in nanotechnology enabled the development of advanced nanocomposites with superior properties for engineering applications especially in automotive and aerospace industries. Among this carbonaceous nano materials like MWCNT have got more attention. Addition of MWCNT in metal matrix results in retardation of friction coefficient and improvement on other mechanical properties based on its dispersion. MWCNT won't have sufficient space to occupy over the powder surface, when the addition is beyond a limit and acts as a solid lubricant during milling. Investigations on self lubricating property during milling were done by using scanning electron microscope, X-ray diffraction and powder density. Uniform dispersion was the bottleneck to utilize their attractive properties of the reinforcement. An attempt had been done for a uniform dispersion during premixing process using a combination of ultra-sonication, magnetic and mechanical stirring followed by high energy ball milling. © 2019 Elsevier Ltd.

World University root node

Materials Today: Proceedings

Self lubricating property of MWCNT in AA2219 composites during high energy ball milling

Bearings and chains are important industrial machine components used in wide range of heavy cyclical load applications. Main aim of this research work is to conduct a metallurgical investigation of failure analysis in failed bearing and chain parts. The failure analysis is carried out by chemical analysis, optical metallography, hardness analysis and scanning electron microscopy (SEM) analysis. In failed bearing inner race ways ridged marks were perceived due to electrical pitting and outer race ball groove worn-out on one side due to axial thrust load. Bearing balls have surface spalling due to contact fatigue. In chain failed bush multiple crack fronts are observed in longitudinal and circumferential. Crack geometry and fracture surface indicates failure through impact fatigue mode. The fracture surface indicated quasi cleavage fracture mode near the crack origins. The results in both investigations suggest that the major common causes of failures are due to over load, fatigue, wear and unsuitable material selection. MoS2coating, thin dense chromium coating and thin hard titanium nitride coating in all bearing components has been suggested to further improve the wear resistance and fatigue strength. Material SAE 8620 alloy steel for chain bush has been suggested to further improve life to withstand in the impact load conditions. © 2019 Elsevier Ltd.

Metallurgical investigation of failure analysis in industrial machine components

The present study develops the evaluation model based on FMEA and AHP integrated with GRA VIKOR under fuzzy environment to evaluate the greatest risk for processes in the production of dust cap assembly in the propeller shaft manufacturing industry. Three risk factors S, O, D and their weights are treated as fuzzy triangular linguistic variables to eliminate the risk for production. FAHP is used to compute the weights of S, O, D whereas GRA VIKOR is used to obtain the final ranking of a risk alternative. Here, the risk factors and their weights are treated as fuzzy triangular linguistic variables for eliminating the risk of subjective quantification and similarity of risk priority number (RPN). Among the various failures, drawing dimension failure and blanking of blank failure are obtained as the most serious failure modes using fuzzy GRA VIKOR. Copyright © 2019 Inderscience Enterprises Ltd.

International Journal of Productivity and Quality Management

A novel approach for failure mode and effect analysis in propeller shaft manufacturing industry using fuzzy analytic hierarchy process and GRA VIKOR

The utilization of the sandwich composite sheets for the specific industrial application depends upon its material properties. The present study investigates the mechanical and thermal properties of Al1050/SS304 sandwich composite sheets which could be used for the manufacturing of automobile sheet metal components such as a car body. The XRD (X-ray powder diffraction) and FTIR (Fourier-transform infrared spectroscopy) are performed to investigate the molecular structural arrangement and adhesive bonds whereas the composite wall test is performed to investigate the thermal conductivity by using different approaches. The experimental approach integrated with the analytical approach is utilized to validate the obtained thermal conductivity using a numerical approach. The thermal conductivity of 2.84 W mK-1 is obtained by using a numerical approach which is in good correlation with the experimental results. © 2020 The Author(s). Published by IOP Publishing Ltd.

Fulltext

Materials Research Express

Investigation of thermal properties of Al1050/SS304 sandwich composite sheet by using a numerical, analytical and experimental approach

In recent days, the behaviour of wind flow around the buildings receives more interest among urban planners, architects, researchers and wind engineers. Hence, these wind flow patterns are assessed extensively using CFD (Computational Fluid Dynamics) simulations, as it re-creates the atmospheric and wind tunnel environment following the turbulence parameters. This paper presents a logical assessment using IDDES (Improved Delayed Detached Eddy Simulation) turbulence model in CFD for predicting wind pressure coefficients and flow features on and around a 300:1 scaled setback tall building model at 0° and 90° AOI (Angle of Incidence) under open terrain condition. The computation is based on gird sensitivity study and validation with Boundary Layer Wind Tunnel (BLWT) experiment measurements. The evaluation shows that the downdraught and downwind effects are suppressed by the increasing wind pressure distribution along the height. The results demonstrate that IDDES can reproduce wind pressure coefficients and aerodynamic coefficients of the setback building accurately. The maximum deviation of the wind pressure coefficients (Cp rms) is found to be 12% in CFD when compared with wind tunnel measurements. Besides, the CFD simulation demonstrates the wind flow distribution patterns, size of re-circulation, wake separation zones and velocity profiles in a three-dimensional plane which are quantified concerning the width of the building. © 2019, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.

VIT Unitversity

Building Simulation

Experimental and computational investigation of outdoor wind flow around a setback building

In this article, we present highly sensitive and reliable nitrogen gas flow sensors based on surface modified n-type (n-Si) and p-type (p-Si) silicon wafers. The surfaces of n-Si and p-Si wafers were coated with octyltrichlorosilane (OTS) molecules. The surface modified n-Si and p-Si wafers were used as sensing elements. The sensing elements were kept on the 45° angle inclined to the experimental mount and nitrogen gas was flown over the inclined surface at subsonic velocities. The flow induced voltage generation is caused by the interplay between the mechanisms of Bernoulli's principle and Seebeck effect. The experimental results show that the half coated and full coated n-Si and p-Si wafers generate more voltage than that of the uncoated at a given velocity. In the case of n-Si wafers, the half coated surface generated voltage was ≈4.80 times than that of the uncoated surface. In the case of p-Si wafers, the half coated surface generated voltage was ≈3.83 times than that of the full coated. The surface analysis of the half and full coated surfaces show that the OTS SAM molecules on n-Si surfaces were homogeneous and well ordered, however on p-Si surfaces, the OTS SAM molecules were heterogeneous and disordered. The enhanced voltage generations and high sensitivities are caused by an effective change in the gradient of Fermi energy (EF) due to OTS SAM coating. The experimental observations and theoretical analysis of enhanced voltage generation show that the OTS surface modification causes synergism of different mechanisms, contributing to the cumulative increase of flow induced voltage. The effect of aging process on the reliability of the half coated OTS/n-Si and OTS/p-Si sensors were tested for 24 h, 30 days and 90 days, the experimental results confirm that the flow induced voltages are consistent and reproducible and both the OTS/n-Si and OTS/p-Si sensors are very reliable. The investigation of the effects of the coverage of the OTS SAM and the angle of inclination on the flow induced voltage shows that the 50% coverage of the OTS/n-Si, OTS/p-Si and the 45° angle of inclination produced a maximum flow induced voltage at any given velocity. © 2018 Elsevier B.V.

Department of Thermal and Energy Engineering

Vellore Campus

Sensors and Actuators A: Physical

Highly sensitive and reliable octyltrichlorosilane coated silicon sensors for nitrogen gas flow detection

We synthesized the gold nanoparticles (AuNPs) using wedelolactone (WDL) and characterized them using UV-visible spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopic (SEM), transmission electron microscopic (TEM), energy dispersive X-ray diffraction, and atomic force microscopic (AFM) studies. The electronic spectrum exhibited an absorption peak at 535 nm. The FT-IR results proved that WDL was stabilized on the surface of AuNPs by acting as a capping or reducing agent. The crystalline structure was affirmed by XRD pattern and the spherical shape of WDL-AuNPs was evidenced by SEM, TEM, and AFM. The synthesized WDL-AuNPS were evaluated for anti-diabetic activity in pancreatic RIN-5F cell lines. In vitro results showed that WDL-AuNPs did not only improve the insulin secretion affected by di-(2-ethylhexyl) phthalate (DEHP), but also the cell viability in RIN5F cells. WDL-AuNPs treatment modulates the pro-apoptotic proteins and anti-apoptotic proteins expression to prevent the cells undergoing apoptosis in DEHP-exposed RIN-5F cells. The exposure of DEHP causes an increase in ROS production and lipid peroxidation levels. The free radical scavenging and antioxidant properties of WDL-AuNPs increase the deleterious effect caused by DEHP. On the other side, WDL-AuNPs increase mRNA expressions of insulin-signaling proteins in RIN-5F cells. This study concludes that WDL-AuNPs can be successfully used to regulate the expression of Bcl-2 family proteins, reduce lipid peroxidation, and to improve the secretion of antioxidants and insulin through the GLUT2 pathway in RIN-5F cell lines.

Department of Biotechnology

School of Bio Sciences and Technology

Antioxidants

Antidiabetic Activity of Gold Nanoparticles Synthesized Using Wedelolactone in RIN-5F Cell Line

In the present situation, the minimal percentage elimination of synthetic fibers as well leads to giving better environmental support.This study has been concentrated on the reduction of polymer materials and incorporation of natural fiber to determine the vibration in hybrid fiber reinforced polymer matrix composites. Three different natural fabric (jute, sisal and hemp), resin (vinlyester, epoxy and general purpose) and volume of natural fiber incorporation were involved for preparation of samples. An analysis was carried out to study the vibration performance hybrid fiber reinforced polymer matrix composites. Design of experiments was completed by Taguchi’s approach to find the level influence of the type of synthetic resin, type of natural fabric and the volume of natural fabric of vibration behavior in the composites using the ANOVA technique. © 2019, Scibulcom Ltd. All rights reserved.

Journal of the Balkan Tribological Association

Vibration and damping characteristics of hybrid (glass- jute/ sisal/ hemp) fiber reinforced polymer matrix composites to protect environment by natural fiber

The vehicles usage is increasing day by day due to the recent, technological development in the automotive field. In a competitive global market in order to survive, the reliability needs to be ensured, through a proper monitoring system. Brake system is one such control component, in which much focus is very much essential. An efficient brake system should provide reliable and effective performance in order to ensure the safety. If it is not properly monitored, it may lead to a serious catastrophic effect such as accidents, brake down, etc. Hence, the brake system needs to be monitored continuously. In this study, an experimental investigation was carried out for monitoring the brake system using vibration signals. An experimental setup which resembles the brake system was fabricated. The vibration signals were acquired under various brake condition such as good and faulty. From the acquired vibration signals, the features were extracted using statistical and histogram feature extraction techniques and feature selection was carried out. The selected features were then classifieds using a Naive Bayes and Bayes Net a classifier. The classification accuracy of all the algorithms were compared for finding the best feature classifier model for monitoring the brake condition. © 2019 IOP Publishing Ltd. All rights reserved.