Showing papers in "Journal of The Institution of Engineers : Series C in 2019"
TL;DR: In this article, the primary recycled acrylonitrile butadiene styrene (ABS) and polyamide 6 (PA6) has been selected as matrix material with bio-degradable and bio-compatible banana fibers (BF) as reinforcement.
Abstract: In the present study efforts have been made to prepare functional prototypes with improved thermal, mechanical and morphological properties from polymeric waste for sustainability. The primary recycled acrylonitrile butadiene styrene (ABS) and polyamide 6 (PA6) has been selected as matrix material with bio-degradable and bio-compatible banana fibers (BF) as reinforcement. The blend (in form of feed stock filament wire) of ABS/PA6 and BF was prepared in house by conventional twin screw extrusion (TSE) process. Finally feed stock filament of ABS/PA6 reinforced with BF was put to run on open source fused deposition modelling based three dimensional printer (without any change in hardware/software of the system) for printing of functional prototypes with improved thermal/mechanical/morphological properties. The results are supported by photomicrographs, thermographs and mechanical testing.
56 citations
TL;DR: It has been found that Hyundai Ioniq electric outperforms over other alternatives based on chosen criteria and the stability of the result obtained is established through a sensitivity analysis.
Abstract: There has been a paradigm shift towards electric vehicles (EVs) in the mobility sector to reduce green-house gas (GHG) emission and its impact on environment. The aim of this paper is to propose a holistic model for selection and ranking of a group of battery EVs using multi-attributive border approximation area comparison (MABAC) method considering various technical and operational attributes like fuel economy, base model pricing, quick accelerating time, battery range and top speed. The stability of the result obtained by this method is established through a sensitivity analysis. A sample of seven potential alternatives has been considered for study. It has been found that Hyundai Ioniq electric outperforms over other alternatives based on chosen criteria.
31 citations
TL;DR: A simplified introduction and implementation details for the incorporation of NURBS based IGA technique within the existing FEA code is presented and it is shown that with little modifications, the available standard code structure of FEA can be adapted for IGA.
Abstract: Isogeometric analysis (IGA) is a recently introduced technique that employs the Computer Aided Design (CAD) concept of Non-uniform Rational B-splines (NURBS) tool to bridge the substantial bottleneck between the CAD and finite element analysis (FEA) fields. The simplified transition of exact CAD models into the analysis alleviates the issues originating from geometrical discontinuities and thus, significantly reduces the design-to-analysis time in comparison to traditional FEA technique. Since its origination, the research in the field of IGA is accelerating and has been applied to various problems. However, the employment of CAD tools in the area of FEA invokes the need of adapting the existing implementation procedure for the framework of IGA. Also, the usage of IGA requires the in-depth knowledge of both the CAD and FEA fields. This can be overwhelming for a beginner in IGA. Hence, in this paper, a simplified introduction and implementation details for the incorporation of NURBS based IGA technique within the existing FEA code is presented. It is shown that with little modifications, the available standard code structure of FEA can be adapted for IGA. For the clear and concise explanation of these modifications, step-by-step implementation of a benchmark plate with a circular hole under the action of in-plane tension is included.
29 citations
TL;DR: In this article, the effects of various tool shoulder end feature on the temperature and mechanical properties of the 6082 aluminum alloy were investigated, and the experimental results showed that the axial force during the welding is considerably reduced by using tools with shoulder end features.
Abstract: Understanding the temperature generation around the tool shoulder contact is one of the important aspects of the friction stir welding process. In the present study, the effects of various tool shoulder end feature on the temperature and mechanical properties of the 6082 aluminum alloy were investigated. The experimental results show that the axial force during the welding is considerably reduced by using tools with shoulder end features. The detailed observation revealed that around the tool shoulder contact, the amount of heat generation is higher between trialing edge (TE) to retreating side-leading edge corner (RS-LE) counter clockwise direction and lower between RS-LE to TE clockwise direction. Out of the four shoulder end featured tools, the welds produced with ridges shoulder tool resulted in superior properties with significantly lower axial force (approximately 32%) compared to plane shoulder tool.
19 citations
TL;DR: In this paper, a grey-fuzzy hybrid approach has been applied to optimize the wear behavior on aluminium metal matrix composites (AMCMC) filler by coconut shell ash (CSA) on pin-on-disc setup.
Abstract: This paper deals with optimization of wear behaviour on aluminium metal matrix composites (AMC) filler by coconut shell ash (CSA) on pin-on-disc setup. The Al-CSA composites are fabricated with various volume percentages such as 5, 10 and 15% of CSA using compo casting technique. The properties of Al-CSA composites have been improve with increasing volume of CSA in base matrix. The experiments are carried out with three process parameters: load, percentage of CSA and sliding distance; and three adequate responses: wear (µm), wear rate (mm3/m) and coefficient of friction. This studied, a hybrid approach (that is, Grey-fuzzy) has been applied to optimizing the several responses. The fuzzy logic concept has been used for handling the uncertainty in the decision-making process. Analysis of variance (ANOVA) shown that the highest influencing parameter is load, followed with sliding distance and percentage of CSAp to the overall tribological performance.
19 citations
TL;DR: From numerical experiments, it can be observed that the SDWLS based gradients scheme improves the solution accuracy as well as solution quality on unstructured mesh along with the efficiency of the present approach.
Abstract: In practice, unstructured meshes are preferred choice for solving flows involving complex geometries. However obtaining the higher order accuracy on the unstructured mesh has always been a challenging task. In this paper, a new high-resolution scheme based on solution dependent weighted least squares (SDWLS) gradients is developed and applied to compute incompressible viscous flows over unstructured meshes. The artificial compressibility based formulation is utilized for incompressible Navier-Stokes equations. The dual time stepping approach is utilized to simulate time accurate incompressible flows. The Harten Lax and van Leer with contact for artificial compressibility (HLLC-AC) Riemann solver is used for evaluating convective fluxes whereas viscous fluxes are evaluated in central differencing manner. Sufficient numbers of benchmark problems are presented here to demonstrate the capability of the SDWLS based gradients scheme to produce high accuracy results over the unstructured meshes. From numerical experiments, it can be observed that the SDWLS based gradients scheme improves the solution accuracy as well as solution quality on unstructured mesh along with the efficiency of the present approach.
18 citations
TL;DR: In this paper, a gas metal arc welding (GMAW) cladding is used to protect the surface of relatively lower grade structural steels from corrosion and/or erosion wear by depositing high grade stainless steels onto them.
Abstract: Among different weld cladding processes, gas metal arc welding (GMAW) cladding becomes a cost effective, user friendly, versatile method for protecting the surface of relatively lower grade structural steels from corrosion and/or erosion wear by depositing high grade stainless steels onto them. The quality of cladding largely depends upon the bead geometry of the weldment deposited. Weld bead geometry parameters, like bead width, reinforcement height, depth of penetration, and ratios like reinforcement form factor (RFF) and penetration shape factor (PSF) determine the quality of the weld bead geometry. Various process parameters of gas metal arc welding like heat input, current, voltage, arc travel speed, mode of metal transfer, etc. influence formation of bead geometry. In the current experimental investigation, austenite stainless steel (316) weld beads are formed on low alloy structural steel (E350) by GMAW using 100% CO2 as the shielding gas. Different combinations of current, voltage and arc travel speed are chosen so that heat input increases from 0.35 to 0.75 kJ/mm. Nine number of weld beads are deposited and replicated twice. The observations show that weld bead width increases linearly with increase in heat input, whereas reinforcement height and depth of penetration do not increase with increase in heat input. Regression analysis is done to establish the relationship between heat input and different geometrical parameters of weld bead. The regression models developed agrees well with the experimental data. Within the domain of the present experiment, it is observed that at higher heat input, the weld bead gets wider having little change in penetration and reinforcement; therefore, higher heat input may be recommended for austenitic stainless steel cladding on low alloy steel.
17 citations
TL;DR: The clonal selection algorithm (CSA) is applied for the simultaneous scheduling to reduce backtracking as well as distance travel of AGVs within the FMS facility.
Abstract: The flexible manufacturing system (FMS) constitute of several programmable production work centers, material handling systems (MHSs), assembly stations and automatic storage and retrieval systems. In FMS, the automatic guided vehicles (AGVs) play a vital role in material handling operations and enhance the performance of the FMS in its overall operations. To achieve low makespan and high throughput yield in the FMS operations, it is highly imperative to integrate the production work centers schedules with the AGVs schedules. The Production schedule for work centers is generated by application of the Giffler and Thompson algorithm under four kind of priority hybrid dispatching rules. Then the clonal selection algorithm (CSA) is applied for the simultaneous scheduling to reduce backtracking as well as distance travel of AGVs within the FMS facility. The proposed procedure is computationally tested on the benchmark FMS configuration from the literature and findings from the investigations clearly indicates that the CSA yields best results in comparison of other applied methods from the literature.
16 citations
TL;DR: In this paper, a compound parabolic solar collector (CPC) with evacuated tubes is fabricated, and the experimental results show that the best thermal performance from the fabricated CPC with evacuated tube is found at 1300h, with 0.31m aperture width and 1.72m absorber pipe length.
Abstract: In this research work, compound parabolic solar collector (CPC) with evacuated tubes is fabricated. Main benefit of CPC is that there is no requirement of solar tracking system. With fabricated CPC; outlet temperatures of flowing fluid, instantaneous efficiencies, useful heat gain rates and inlet exergies (with and without considering Sun’s cone angle) are experimentally found. Observations are taken at different time intervals (1200, 1230, 1300, 1330 and 1400 h), mass flow rates (1.15, 0.78, 0.76, 0.86 and 0.89 g/s), ambient temperatures and with various dimensions of solar collector. This research work is concluded as; maximum instantaneous efficiency is 69.87% which was obtained with 0.76 g/s flow rate of water at 1300 h and 42°C is the maximum temperature difference which was also found at same time. Maximum inlet exergies are 139.733 and 139.532 kW with and without considering Sun’s cone angle at 1300 h, respectively. Best thermal performance from the fabricated CPC with evacuated tubes is found at 1300 h. Maximum inlet exergy is 141.365 kW which was found at 1300 h with 0.31 m aperture width and 1.72 m absorber pipe length.
16 citations
TL;DR: In this paper, various equivalent stress intensity factor (SIF) models are used for prediction of mixed mode fatigue life using the Paris' law and compared to assess their efficacy in prediction of the life close to the experimental findings as there are no guidelines/suggestions available on selection of these models for accurate or conservative predictions of fatigue life.
Abstract: Accurate information regarding crack growth times and structural strength as a function of the crack size is mandatory in damage tolerance analysis. Various equivalent stress intensity factor (SIF) models are available for prediction of mixed mode fatigue life using the Paris’ law. In the present investigation these models have been compared to assess their efficacy in prediction of the life close to the experimental findings as there are no guidelines/suggestions available on selection of these models for accurate and/or conservative predictions of fatigue life. Within the limitations of availability of experimental data and currently available numerical simulation techniques, the results of present study attempts to outline models that would provide accurate and conservative life predictions.
15 citations
TL;DR: Scope of developing a damper where tool vibration can be suppressed by varying the damping ability based on requirement was established and inferred that the control of tool vibration was effective by utilizing appropriate damping mechanism in the boring process.
Abstract: In boring process, tool vibration is an important parameter which results in progressive tool wear, poor surface finish and cutting tool damage. This tool vibration was reduced by passive, semi-active and active techniques which are used by various researchers in the past. In this paper, various techniques employed to prevent tool vibration in boring operation are reviewed, analyzed and presented. It was inferred that the control of tool vibration was effective by utilizing appropriate damping mechanism in the boring process. Also, from the overall review of the literature, it was observed that as the tool wear started to progress, the tool vibration gets increased which leads to failure of the tool. In this review paper, scope of developing a damper where tool vibration can be suppressed by varying the damping ability based on requirement was established.
TL;DR: This case study presents the availability evaluation method of thermal power plants for conducting performance analysis in Indian environment and highlights procedure for finding critical plants/units/subsystems and helps in deciding preventive maintenance program.
Abstract: This case study presents the availability evaluation method of thermal power plants for conducting performance analysis in Indian environment. A generic availability model has been proposed for a maintained system (thermal plants) using reliability block diagrams and fault tree analysis. The availability indices have been evaluated under realistic working environment using inclusion exclusion principle. Four year failure database has been used to compute availability for different combinatory of plant capacity, that is, full working state, reduced capacity or failure state. Availability is found to be very less even at full rated capacity (440 MW) which is not acceptable especially in prevailing energy scenario. One of the probable reason for this may be the difference in the age/health of existing thermal power plants which requires special attention of each unit from case to case basis. The maintenance techniques being used are conventional (50 years old) and improper in context of the modern equipment, which further aggravate the problem of low availability. This study highlights procedure for finding critical plants/units/subsystems and helps in deciding preventive maintenance program.
TL;DR: In this paper, the microstructural and mechanical properties of pure aluminium graphene nano-platelets (GNPs) composites were investigated and compared to other weight percentages due to high surface area and curled nature of graphene and makes it potential for diverse applications.
Abstract: The present investigation deals with the microstructural and mechanical properties of pure aluminium graphene nano-platelets (GNPs) composites. The contents of GNPs were varied from 0.50 to 2 wt% in pure aluminium matrix. The composites fabrication was done through stir casting technique, and the investigations revealed that pure Al–0.5% GNPs composite displayed better mechanical properties in comparison with pure Al–1% GNPs, 1.5% GNPs and 2% GNPs composites for tensile strength and hardness test. The SEM, fractographic analysis, XRD and TEM analyses were examined to investigate the surface morphology, and phase analysis confirms that there is a uniform distribution of GNPs in the base matrix (pure Al) and results in low porosity. This leads to a considerable improvement in the mechanical properties of pure Al–0.5% GNPs compared to other weight percentages due to high surface area and curled nature of graphene and makes it potential for diverse applications.
TL;DR: In this article, an attempt to further augment the surface hardness and understand its effects on the surface morphology was performed through heat treatments at 500°C for different duration of times, and the results showed the presence of Al2Ti and AlTi3N.
Abstract: Successful titanium carbonitride (TiCN) coating on AA7075 plates using the PVD technique depends upon many variables, including temperature, pressure, incident angle and energy of the reactive ions. Coated specimens have shown an increase in their surface hardness of 2.566 GPa. In this work, an attempt to further augment the surface hardness and understand its effects on the surface morphology was performed through heat treatments at 500°C for different duration of times. Specimen’s heat treated at 500°C for 1 h exhibited a maximum surface hardness of 6.433 GPa, corresponding to an increase of 92.07%. The XRD results showed the presence of Al2Ti and AlTi3N and indicate the bond created between them. Unit cell lattice parameters in the XRD data are calculated using Bragg’s law. The SEM images exhibit increasing crack sizes as the heat treatment time is increased. From the studies, the heat treatment duration can be optimized to 1 h, which exhibited an augmented surface hardness, as further increases in durations caused a drop in the surface hardness. The heat treatment effectively modified the surface hardness. Equations providing the relationships that temperature and time have with the reaction parameters are presented.
TL;DR: In this article, the authors tried to add some comprehensive insight on solar energy framework, policy, outlook and socio-economic challenges of India, including its prominent areas of working such as grid independent and utility-scale power production using CSP or PV power plants, rural as well as urban electrification using PV, solar powered public transportation systems, solar power in agrarian society.
Abstract: Solar energy technology has grabbed a worldwide interest and attention these days. India also, having a huge solar influx and potential, is not falling back to feed its energy demand through non-conventional energy sources such as concentrating solar power (CSP) and photovoltaic (PV). This work will try to add some comprehensive insight on solar energy framework, policy, outlook and socio-economic challenges of India. This includes its prominent areas of working such as grid independent and ‘utility-scale’ power production using CSP or PV power plants, rural as well as urban electrification using PV, solar powered public transportation systems, solar power in agrarian society—water pumping, irrigation, waste management and so on and so forth. Despite the fact that, a vast legion of furtherance and advancement has been done during the last decade of solar energy maturation and proliferation, improvements could be suggested so as to augment the solar energy usage in contrast to conventional energy sources in India.
TL;DR: In this paper, a numerical simulation of the turbulent separation reattachment flow under high Reynolds number in different curvature ratios has been performed in a 90-degree bend pipe and the separation region and separation-reattachment points are reported.
Abstract: A turbulent separation flow is one of the most complex flows in existence. Flow separation and reattachment phenomena take place on the lower curved wall under high-pressure gradient for high Reynolds number in different pipe bends. The present study deals with the numerical simulation of the turbulent separation reattachment flow under high Reynolds number in different curvature ratios. Through making use of k–e turbulence model, the turbulent single-phase flow via a 90-degree bend pipe is studied numerically. A more precise research has been conducted to discover the impact of Reynolds number (Re) as well as curvature ratio (Rc/D) on the reattachment and separation of flow inside the pipe bend. The separation region and the separation–reattachment points are reported here. Additionally, mean statistics of the primary and secondary velocity field flows in diverse sections and the occurrence of Dean vortices have been shown. It has been observed that bends with low curvature ratio enable flow separation to be clearly visualized. Distribution of velocity depicted that the secondary motion is clearly encouraged by the progress of fluid from the inner to the outer wall region of the bend resulting in the separation of flow. In general, this numerical study analyses the flow separation phenomenon and predicts the separation and reattachment locations in 90° bend pipe for different Reynolds numbers and bend curvatures.
TL;DR: In this article, the fracture properties such as critical energy release rate in mode I (GIc) and mode II (GIIc) of an interface between two sheets of same material were modified to determine these properties between the sheets of dissimilar materials and thickness.
Abstract: The existing techniques to determine the fracture properties such as critical energy release rate in mode I (GIc) and mode II (GIIc) of an interface between two sheets of same material were modified to determine these properties between the sheets of dissimilar materials and thickness. In addition, the interface shear strength (ISS) was also determined. Experiments were carried out on the specimens made of a pre-cracked thin aluminium alloy skin and a Fiber reinforced polymer (FRP) patch. Two kinds of surface preparation of the aluminium skin were employed; (i) emery-paper roughened surface (ERS) and (ii) Sodium Hydroxide (NaOH) treated surface (NTS). GIc of ERS specimen was found to be 36.1 J/m2, while it was found to be much higher for NTS specimens, that is, 87.3 J/m2. GIIc was found to be 282.4 J/m2 for ERS specimens and much higher as 734.5 J/m2 for NTS specimens. ISS was determined as 32.6 MPa for ERS specimen and significantly higher for NTS specimen, that is, 44.5 MPa. The micrographs obtained from a field emission-scanning electron microscope (FE-SEM) and the surface roughness test showed that the NTS was significantly rougher than the ERS, explaining the higher values of all the three kinds of NTS specimens.
TL;DR: In this article, the effect of free stream turbulence levels and their frequencies on wake structures and shedding frequencies of circular cylinders is studied in detail, and it is observed that the alteration in wake structure and shedding frequency depend strongly on the frequencies and the amplitudes of upstream disturbances besides the diameter of the circular cylinder.
Abstract: Circular cylinders experiencing different upstream flow conditions have been studied for low Reynolds numbers using hot-wire anemometry and smoke flow visualizations. The upstream condition of the cylinder in the test section is varied using a wire mesh placed at the entrance of the test section. The Reynolds number is varied by varying the diameter of the cylinder and the mean velocity in the test section. Smooth cylinders of diameter varying from 1.25 to 25 mm are used in the present study. A multi-channel hot-wire anemometry is used for measuring the fluctuating velocities in the test section and the wake behind the cylinder. The sectional views of the wake behind the cylinder are obtained using a 4 MP CCD camera, 200 mJ pulsed laser and a fog generator. The flow quality in the test section is examined using higher order turbulence statistics. The effect of free stream turbulence levels and their frequencies on wake structures and the shedding frequencies of circular cylinders are studied in detail. It has been observed that the alteration in wake structure and the shedding frequency depend strongly on the frequencies and the amplitudes of upstream disturbances besides the diameter of the circular cylinder.
TL;DR: In this paper, the authors present a solution through case study approach for improving the issue of rejection rate in the spring support in a medical device manufacturing industry by using SPC and define-measure-analyze-improve-control (DMAIC) approach which provide breakthrough quality improvements in short period of time.
Abstract: Statistical process control (SPC) is an excellent quality assurance tool to improve the quality of manufacture and end-customer satisfaction. It uses process monitoring charts to record the key quality characteristics of the component/part in manufacture. This research paper elaborates on one such key quality characteristics of the manufacturing of a spring support in the Tissue Dissector Device. This paper presents a creative solution through case study approach for improving the issue of rejection rate in the spring support in a medical device manufacturing industry by using SPC and define-measure-analyze-improve-control (DMAIC) approach which provide breakthrough quality improvements in short period of time.
TL;DR: In this paper, an attempt is made to integrate 2014 Al alloy with Al2O3p by two stage stir casting with addition level of reinforcement maintained at 9 and 12 ¼ wt.
Abstract: Metal matrix composites (MMC’s) form appropriate choice of materials where there is a demand for stiffness, strength combined with low weight for different applications. The applications of Aluminum based MMC’s as engineering materials has been exceedingly increased in almost all industrial sectors. Aluminum strengthened with Al2O3p gives excellent physical and mechanical properties like high hardness, low density, high electrical conductivity etc., which are generally used in the field of aerospace, automobile and industrial applications. In present work, an attempt is being made to integrate 2014 Al alloy with Al2O3p by two stage stir casting with addition level of reinforcement maintained at 9 and 12 wt%. Microstructural characterization carried out using scanning electron microscopy showed fairly uniform distribution of Al2O3p with grain refinement of the matrix. These prepared composites are mechanically characterized as per the ASTM standards using computerized universal testing machine. Improvements in tensile strength, density and hardness of the prepared composites were observed with increase in the reinforcement wt%. Percentage improvements of 5.09% (9 wt%), 17.65% (12 wt%) in terms of tensile strength and 29.18% (9 wt%), 43.69% (12 wt%) in terms of hardness were obtained respectively.
TL;DR: In this paper, a quadrilateral finite element of four nodes with 32 DOF was used for stress analysis in perforated laminates. And the results of the analysis showed that the stress concentration values are considerably affected by increasing the orientation angle of the fibers and degree of orthotropy.
Abstract: The design of high-performance composite structures frequently includes discontinuities to reduce the weight and fastener holes for joining. Understanding the behavior of perforated laminates is necessary for structural design. In the current work, stress concentrations taking place in laminated and isotropic plates subjected to tensile load are investigated. The stress concentrations are obtained using a recent quadrilateral finite element of four nodes with 32 DOFs. The present finite element (PE) is a combination of two finite elements. The first finite element is a linear isoparametric membrane element and the second is a high precision Hermitian element. One of the essential objectives of the current investigation is to confirm the capability and efficiency of the PE for stress determination in perforated laminates. Different geometric parameters, such as the cutout form, sizes and cutout orientations, which have a considerable effect on the stress values, are studied. Using the present finite element formulation, the obtained results are found to be in good agreement with the analytical findings, which validates the capability and the efficiency of the proposed formulation. Finally, to understand the material parameters effect such as the orientation of fibers and degree of orthotropy ratio on the stress values, many figures are presented using different ellipse major to minor axis ratio. The stress concentration values are considerably affected by increasing the orientation angle of the fibers and degree of orthotropy.
TL;DR: An integrated method is developed by combining Fuzzy analytical hierarchy process and Technique for Order Preference by Similarity to Ideal Solution, and the same is proposed for a 100 W solar panel selection.
Abstract: Solar energy has been one of the most utilized resources of non-conventional energy compared to wind and tidal energies. A photovoltaic system is used to generate solar energy by photovoltaics. The advancements emerged in solar power generation resulted as an economic alternative compared to conventional coal- or gas-based thermal power plants which are not only costly but pollute environment. The solar panel plays a vital role in a photovoltaic system, and a considerable research work is being done globally in order to reduce costs with better efficiency. Selection of solar panel encompasses complex factors involving both subjective and quantifiable parameters. Balancing both subjective and quantifiable parameters is essential for selecting appropriate solar panel. An integrated method is developed by combining Fuzzy analytical hierarchy process and Technique for Order Preference by Similarity to Ideal Solution, and the same is proposed for a 100 W solar panel selection. The case study was conducted to validate the proposed model for solar panel selection.
TL;DR: In this paper, the microstructures of the salt spray tested coatings were investigated by scanning electron microscope and X-ray diffraction tests were conducted on specimens to determine the atomic and molecular structure of the surface crystals and the unit cell dimensions.
Abstract: Corrosion is one of the most important marine difficulties that cause long term problems, occurring in ships and submarines surrounded by a corrosive environment when coupled with chemical, temperature and stress related conditions. Corrosion of marine parts could lead to severe disasters. Coatings and heat treatment in a very effective way could be used to protect the aluminium parts against corrosion. The present case study focuses on the corrosion and microstructural properties of TiCN coatings fabricated on Al-7075 aluminium alloy substrate by using Physical Vapour Deposition technique. Corrosion properties of specimen’s heat treated at 500 °C at durations of 1, 4, 8 and 12 h were tested through salt spray test. According to D-1193, ASTM standard, corrosion resistance of coated and heat treated Al-7075 samples were investigated in solution kept at 95 °F with a pH of 6.5–7.2, with 5 sections of NaCl to 95 sections of type IV water. The specimen’s heat treated for 1 h showed positive corrosion resistance, while the specimens treated for longer durations had the opposite effect. The microstructures of the salt spray tested coatings were investigated by scanning electron microscope. X-ray diffraction tests were conducted on specimens to determine the atomic and molecular structure of the surface crystals and the unit cell dimensions. The corrosion mechanisms of the coated specimens under the heat treated conditions have been explored.
TL;DR: In this paper, the effects of longitudinal and lateral stresses on the divergence speed and flutter characteristics of an elastic plate in a supersonic gas flow were analyzed by MATLAB coding.
Abstract: The work is devoted to studying the stability of an elastic plate in a supersonic gas flow. This problem arises in the study of the phenomenon of panel flutter, buckling and vibration intensity of airplane and missile thin-walled structures, excited by their interaction with the airflow at high-speed flight. It is important to avoid the panel flutter occurrence to increase the structure lifetime. The vibrations of a rectangular isotropic thin plate in a supersonic airflow are studied to find the flutter speed and analyze it. Using Bubnov–Galerkin method and aerodynamic model by piston theory in supersonic fluid dynamics, effects of longitudinal and lateral stresses on the divergence speed and flutter characteristics of the panel have been analyzed by MATLAB coding. To this end, by finding the panel vibration natural frequencies and drawing the vibration graphs, flutter speed has been determined and stress effects on this speed have been discussed. The numerical results show that initial in-plane stresses have a significant effect on flutter speed of the plate. Compressive longitudinal stress will increase the panel dynamical instability, and stretching stress in this direction will decrease it. Furthermore, compressive stresses in lateral (perpendicular to the flow) direction will decrease the panel dynamical stability, and stretching stress in this direction will increase it. Using this information, the most dynamic stable and unstable zones in airplane structures can be determined.
TL;DR: An experimental investigation of the cavitation behavior of a radial flow pump of metric specific speed 23.62 rpm having different leading edge profiles of the vane is presented in this article, where the results exhibited the trends of noise and vibration with respect to percentage of head drops for all operating conditions.
Abstract: An experimental investigation of the cavitation behaviour of a radial flow pump of metric specific speed 23.62 rpm having different leading edge profiles of the vane is presented. The pump was operated for flow rates from 80 to 120% of the best efficiency point. The measurement included noise and vibration signals apart from the hydraulic parameters. The results exhibited the trends of noise and vibration with respect to percentage of head drops for all operating conditions. It was concluded that the trends were totally different for various flow rates. Hence it is suggested that the criteria to be used for detecting the early cavitation in pump based on noise and vibration signals should be a function of the flow rate. Further, it was found that the range of frequency band for noise and vibration was within 5 kHz with reference to the magnitude of fluctuation. The repeatable predominant frequency of vibration for prediction of cavitation behaviour of this particular pump was established as 0.992 kHz.
TL;DR: In this paper, the strength of cotton spandex woven fabric was optimized through heat setting with the facilitates of a stenter machine with some adjusted industrial setting, where the heat setting was carried out at sufficiently high temperatures with precise time and speed, so that the yarn in the fabric would get set at a desired stretched dimension.
Abstract: The purpose of this research established in this paper was to optimize the strength of cotton spandex woven fabric through heat setting with the facilitates of a stenter machine with some adjusted industrial setting. Heat setting was carried out at sufficiently high temperatures with precise time and speed, so that the spandex yarn in the fabric would get set at a desired stretched dimension. Heat setting parameters were preferred to attain the optimized strength properties of cotton spandex fabric within moderately rigid limits. Heat setting reduced the spandex recovery forces to further compression or extension. Heat setting of cotton spandex fixed the spandex inside. Heat setting also condensed the spandex inside. Due to temperature application, spandex portion gripped the cotton fibers which gave stability in the internal structure of yarn. Trials were conducted in textile mills at various temperatures those were accomplished by heating the fabric at an agreed temperature. Three different nomenclature of cotton spandex fabrics having various composition were used in this experiment to find out the strength parameters. Different temperature varied from 165 °C to 195 °C with the adjusted machine speed from 21 to 25 m per minute (m/min) were applied in this experiment to the get optimum strength. Heat setting was preferably carried out at early stages of the processing zone rather than at the end to avoid yellowing effect while drying. Improper heat seating could discolor the cotton spandex with its companion fibers. Overheat could spoil the elasticity and strength of cotton spandex, therefore it was very important to adjust the temperature and speed accordingly. This experiment proved that, temperature application had an impact over the strength of cotton spandex and also it created a suitable way for the researcher to further experiment in spandex production.
TL;DR: In this article, the authors evaluated the rate of heat exchange enhancement by rectangular plate fins with differing inclinations (0°-30°-60°), shifting Re and heat supply under forced convection, and found that the heat transfer coefficient in 0° fin staggered arrangement is about 17% higher than 30° inline arrangement and 76% more than the vertical plate fin.
Abstract: Heat exchange upgrade is a vital territory of research area. Utilization of reasonable systems can bring about noteworthy specialized points of interest coming about reserve funds of cost. Rectangular plates are viewed as best balance arrangement utilized for heat exchange improvement. This gives an enlargement strategy to heat exchange with beginning of limit layer and vortex development. To assess and look at the rate of heat exchange enhancement by rectangular plate fins with differing inclinations (0°–30°–60°), shifting Re and heat supply under forced convection are the principle destinations of this study. The study is done by fluctuating introductions of fins with various inclinations, input heat supply and Re under forced convection. The coefficient of heat transfer increments observed with the expansion in air speed for all the examined designs. The coefficient of the heat transfer is discovered higher at the edge of introduction of fins at 30° for inline arrangement and 0° for staggered arrangement. Looking at both the arrangements, it is discovered that the heat transfer coefficient in 0° fin staggered arrangement is about 17% higher than 30° inline arrangement and 76% higher than the vertical plate fin. For plate fin heat sink, boundary layer formation and growth results in decrease of the coefficient of heat transfer in forced convection. This issue is overcome by accommodating some rectangular fins on the plate fin. It brings about increment of heat transfer coefficient of the RPFHS under the states of trial factors. As indicated by past research, it is discovered that examination of the plate fin heat sink with various sorts of fins for horizontal orientation is done yet but this investigation expects to discover the upgrade of transfer coefficient of plate fin heat sink for its vertical position with rectangular plates at different inclinations under the shifting scopes of heat input supply, fin arrangements and Reynolds number (Re).
TL;DR: In this article, the authors investigated the effect of length and cross sectional area of the salt bridge on the performance of two chamber salt bridge microbial fuel cells (MFCs).
Abstract: One major problem of two chamber salt bridge microbial fuel cells (MFCs) is the high resistance offered by the salt bridge to anion flow. Many researchers who have studied and optimized various parameters related to salt bridge MFC, have not shed much light on the effect of salt bridge dimensional parameters on the MFC performance. Therefore, the main objective of this research is to investigate the effect of length and cross sectional area of salt bridge and the effect of solar radiation and atmospheric temperature on MFC current output. An experiment has been designed using Taguchi L9 orthogonal array, taking length and cross sectional area of salt bridge as factors having three levels. Nine MFCs were fabricated as per the nine trial conditions. Trials were conducted for 3 days and output current of each of the MFCs along with solar insolation and atmospheric temperature were recorded. Analysis of variance shows that salt bridge length has significant effect both on mean (with 53.90% contribution at 95% CL) and variance (with 56.46% contribution at 87% CL), whereas the effect of cross sectional area of the salt bridge and the interaction of these two factors is significant on mean only (with 95% CL). Optimum combination was found at 260 mm salt bridge length and 506.7 mm2 cross sectional area with 4.75 mA of mean output current. The temperature and solar insolation data when correlated with each of the MFCs average output current, revealed that both external factors have significant impact on MFC current output but the correlation coefficient varies from MFC to MFC depending on salt bridge dimensional parameters.
TL;DR: Numerical simulations were carried out using computational fluid dynamics and fluid–structure interactions for three-lobe journal bearing to study the pressure distribution and the optimized journal bearing position was achieved using a response surface optimization technique.
Abstract: In the work presented here, numerical simulations were carried out using computational fluid dynamics and fluid–structure interactions for three-lobe journal bearing. ANSYS Workbench® software was used for the study. The elastic deformations were also considered for the analysis. The fluid pressure forces and displacements were transferred through inbuilt transfer interface available in the software. The optimized journal bearing position was achieved using a response surface optimization technique. The methodology was validated by comparing numerical results obtained with experimental results available in the literature, and a good agreement was found. The proposed numerical method was implemented to study the pressure distribution in three-lobe journal bearing considered for study at three eccentricity ratios 0.25, 0.6 and 0.75 for various speeds ranging from 1000 to 4000 RPM. Preload factor of 0.5 was considered for the study. The results were compared with a set of experimental data obtained on a test rig developed by the authors.
TL;DR: A surface quality evaluation of a Nickel-Cr-Fe-based Inconel 718 superalloy is presented in this paper, which has many applications in the aero engine and turbine components.
Abstract: This experimental work presents a surface quality evaluation of a Nickel-Cr-Fe based Inconel 718 superalloy, which has many applications in the aero engine and turbine components. However, during machining, the early wear of tool leads to decrease in surface quality. The coating on cutting tool plays a significant role in increasing the wear resistance and life of the tool. In this work, the aim is to study the surface quality of Inconel 718 with TiAlN-coated carbide tools. Influence of various geometrical parameters (tool nose radius, approach angle) and machining variables (cutting velocity, feed rate) on the quality of machined surface (surface roughness) was determined by using central composite design (CCD) matrix. The mathematical model of the same was developed. Analysis of variance was used to find the significance of the parameters. Results showed that the tool nose radius and feed were the main active factors. The present experiment accomplished that TiAlN-coated carbide inserts result in better surface quality as compared with uncoated carbide inserts.