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International Review of
Mechanical Engineering
(IREME)
March 2013
(Vol. 7 N. 3)








    Engine Mapping for Improvement in Fuel Efficiency of Two Stroke SI Engine

    by K. D. Sapate, A. N. Tikekar

    Vol. 7. n. 3, pp. 392-394

     

    Abstract - Fuel prices are increasing continuously all over the world. Also, globally the vehicle density is increasing according to geometric progression which contributes as a major source of air pollution. Therefore, improvement is continuously demanded in design of an efficient engine producing less harmful emissions. Many researcher and engine manufacturers in this field are optimistic and enthusiastically working to achieve these objectives. This work mainly focuses on low cost electronic fuel injection (EFI) system developed for a small two stroke SI engine. Engine mapping plays vital role to reduce emissions and enhance engine performance by providing appropriate amount of fuel quantity at all operating conditions of engine which results in complete combustion. This paper presents the experimental work using engine mapping process with EFI system, graphical user interface based software – Proteous and modified fuel injection system. The experimental results of carburetor mode and EFI mode are included and compared.

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    Keywords: Engine Mapping, Injection, EFI.

     

    The Control of the Handling of a Front Wheel Drive Vehicle by Means of a Magnetorheological Differential

    by M. Terzo, F. Timpone

    Vol. 7. n. 3, pp.395-401

     

    Abstract - This paper presents a semi-active differential, called MRF LSD (MagnetoRheological Fluid Limited Slip Differential) that allows to bias torque between the driving wheels. It is based on the magnetorheological (MR) fluid employment, that allows to change, in a controlled manner, the differential locking torque and, consequently, the torque bias ratio. The device is an adaptive one and allows to obtain an asymmetric torque distribution in order to improve vehicle handling. The device modelling and the control algorithm, realized for this activity, are described. The illustrated results highlight the advantages that are attainable regarding directional behaviour, stability and traction for a front wheel drive (FWD) vehicle. A comparison with a traditional passive limited slip differential has been conducted.

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    Keywords: Vehicle Dynamics, Control, Magnetorheological Fluids.

     

    Implementation of Penalty Method for Optimization of FGM Beams

    by S. Malekian, S. Kamarian, A. Pourasghar

    Vol. 7. n. 3, pp.402-407

     

    Abstract - In this study, optimization of four-parameter power-law distribution of functionally graded (FG) beams resting on elastic foundations for the density with constraint on the frequency parameter is presented. To perform optimization, Genetic Algorithm (GA) is used to find the optimal solution. Genetic Algorithms is most directly suited to unconstrained optimization. Thus, penalty method is implemented for handling the existing constraints. A proper artificial neural network (ANN) is trained by training data sets obtained from generalized differential quadrature (GDQ) method and then is applied to reproduce the behaviour of the structure both in free vibration and density for improving the speed of the optimization process.

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    Keywords: Functionally Graded Beam, Optimization, Genetic Algorithm, Penalty Method, Artificial Neural Network .

     

    Effect of Road Excitation on the Vehicle Vibrations Suspended by Electro -Rheological Damper

    by E. M. Attia, M. F. Mohamed, N. A. Maharem

    Vol. 7. n. 3, pp.408-424

     

    Abstract - Ride with comfort is the most important demand in vehicle industry as it affects directly seats mounting. For that reasons a lot of effort has been made to improve ride comfort by isolating vehicle from road irregularities as possible. That can be done by improving vehicle suspension ability to dampen the vibration induced from road irregularities during vehicle maneuver before it reaches the vehicle body. This work investigates the effect of active damping on vehicle vibrations by presenting mathematical model of full active vehicle suspensions. That model introduced a new active damper tested recently and proved to be efficient. These dampers depend on two kinds of fluids, Electro-Rheological fluid (ER) and Magneto- Rheological fluid (MR), both of them give high damping with a little power cost. Mathematical model is derived for the vehicle suspended by a classical damper or Electro- Rheological (ER) damper. Many types of roads are tested for vibration effect on the driver and suspension of the vehicle. A computer programs are constructed which include a classical damper or (ER) damper and can be implemented on a full vehicle suspension. Also a simulation program (MATLAB-SIMULINK) from which any response to any changes in any parameter can be obtained. A comparison between the types of roads as effect for heave, front and rear wheel suspension was studied. Also effect of voltage input to (ER) damper on vibrations of the vehicle was investigated.

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    Keywords: Vibrations, Roads, ER Damper, Dynamic, Response, Vehicle.

     

    Review of Material Used in Brake Pads

    by C. M. Ruzaidi, H. Kamarudin, J. B. Shamsul, A. M. Mustafa Al Bakri, W. I. Wan Mastura

    Vol. 7. n. 3, pp.425-435

     

    Abstract - Materials used in brake pads determine their behavior, which is important to understand as the brake system is one of the main parts in a vehicle and deals with safety matters. The materials are also often associated with many problems in brake systems, such as low brake wear properties, low coefficient of friction, and fade phenomenon. Development and intense competition in the changing composition of various materials in the brake pad are normal practices in this industry as modifying materials in brake pads is easier than modifying the specifications of the brake system itself. This paper reviews the various materials commonly used as well as recent trends. The function of each material used is also discussed. Many materials perform more than one function and may be put in more than one category.

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    Keywords: Brake Pad, Friction Brake Materials, Binders in Brake Pads.

     

    Dynamic Characteristic Analysis on Half Car Electro Pneumatic Suspension System

    by K. Prabu, J. Jancirani, Dennie John

    Vol. 7. n. 3, pp.436-441

     

    Abstract - This study is focused on isolation of passenger from tremors occurring due to road irregularities. A half-car model is considered to study the pitch acceleration of the body and the dynamic characteristics of front and rear wheels. This study includes an optimal control that ensures the pre-eminent suspension performance by limiting the active generated by the actuators should be within the limit and it is applied between vehicle body and wheel. The effectiveness of the system is examined through simulation with two road disturbance models which were designed to simulate actual road conditions with road irregularity. The influences of the vehicles parameters on the vehicles dynamic characteristic and response are investigated. The results show that the proposed system provides improvement in ride quality while maintaining vehicle manoeuvrability.

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    Keywords: Half Car, Actuator, Low Bandwidth, PID, Ride Comfort, Pitch Acceleration.

     

    Effect of Nanofluid Variable Properties on Natural Convection in a Square Cavity Using Lattice Boltzmann Method

    by A. R. Shahriari, S. Jafari, M. Rahnama, A. Behzadmehr

    Vol. 7. n. 3, pp.442-452

     

    Abstract - In this paper, laminar natural convective of a nanofluid in a square cavity is studied using Lattice Boltzmann Method (LBM). The main objective is to investigate the effects of variable thermal conductivity and dynamic viscosity models for Al2O3–water and TiO2–water nanofluids on flow and heat transfer in this geometry. Hydrodynamics and thermal fields are coupled using the Boussinesq approximation. The influence of pertinent parameters such as solid volume fraction of nanoparticles (0≤φ≤5%), Rayleigh number (Ra =103-106) and the type of nanoparticles on flow and heat transfer are investigated. Good agreement was observed between the present results and those of previous numerical simulation and experimental published work. It is found that fluid flow and temperature field are affected by addition of nanoparticles into water especially for higher Rayleigh numbers. It is indicated that average Nusselt number was more sensitive to the viscosity models than to the thermal conductivity models. A deterioration of the mean Nusselt number was also observed with increasing volume fraction of the nanoparticles for the whole range of Rayleigh number.

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    Keywords: Lattice Boltzmann Method, Nanofluid, Natural Convection, Square Cavity.

     

    Optimization of the Plastic Injection Molding Parameters for Sport Equipment by Using Design of Experiment

    by R. Hussin, R. Mohd Saad, R. Hussin, M. R. M. Hafiezal, M. A. Fairuz

    Vol. 7. n. 3, pp.453-462

     

    Abstract - This Paper, research about the defect on plastic product in injection molding process. During producing a product using injection molding process, various of defects such as warpage, weld lines, shrinkage and sink mark can be occurred. A set of Optimal setting of injection molding parameters is very important to be determined after various trials has been made, because to reduce and controlling the quality on defect of the injection molded product. The purpose of this research is to optimize warpage and shrinkage defect on material Polycarbonate(PC) thermoplastic and simulate the injection molding process using Moldflow Plastic Insight software (MPI).Optical glasses has been selected as a product to be studied and design the model by using UNIGRAPHIC NX 7.5 .The approach based on Design of Experiment has been implemented to analyze and optimize the processing parameters such as mold temperature, melt temperature, packing time, packing pressure, cooling time, cooling temperature, and runner size. Experimental plans available in the form of orthogonal arrays. Software (Minitab) for automatic experiments design and analysis of results based on Design of Experiments (Taguchi Method) were used to find the best setting of injection molding plastic part.

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    Keywords: Plastics Injection Molding, Taguchi’s Method, Warpage and Shrinkage.

     

    Optimizing the Compression Ratio of C.I Engine Fuelled in Sardine Oil Ethyl Ester

    by V. Narasiman, S. Jeyakumar, M. Mani

    Vol. 7. n. 3, pp.463-467

     

    Abstract - This study investigates the performance and emission characteristics of a variable compression ratio diesel engine which is fuelled with sardine oil ethyl ester. A single cylinder four stroke diesel engine was used for the experiments at various load and speed of 1500 rpm. In order to find out optimum compression ratio experiments were carried out on a single cylinder four stroke variable compression ratio diesel engine. Tests were carried out at compression ratios of 16.0, 17.5 and 19.0. Results showed a significant improved performance and emission characteristics at a compression ratio 16.0. It has been observed that there is an increase in Break thermal efficiency, Exhaust gas temperature and Carbon monoxide for compression ratio 16, Hydro carbon and Nitric oxide is lower for compression ratio 16.

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    Keywords: Diesel Engine, Sardine Oil Ethyl Ester, Compression Ratio, Performance, Emission.

     

    Multi Characteristic Optimization in Wire Cut EDM by Using Taquchi Data Envelopment Analysis Based Ranking Methodology

    by L. Savadamuthu, S. Muthu, T. Rakhul, S. Jothimani

    Vol. 7. n. 3, pp.468-473

     

    Abstract - The selection of optimum machining conditions, during wire electric discharge machining process, is of great concern in manufacturing industries these days. The increasing quality demands, at higher productivity levels, require the wire electric discharge machining process to be executed more efficiently. As the process involves more than one response characteristic, it is needed to implement the multi-response optimization methodology’s for optimize the process parameter and ensuring with low cost of manufacturing. This article addresses an approach based on the Taquchi Data Envelopment Analysis-based Ranking methodology(DEAR) for optimizing WEDM operations with multiple responses by using reusable molybdenum wire electrode in Suzhou Baoma BMW 2008 Wirecut EDM. The relation between Input parameters including wire speed, pulse on time, pulse off time, peak current and table feed are optimized with consideration of the multi- response characteristics viz., metal removal rate(MRR),surface roughness(SR) and kerfwidth(KW) on WEDM in industrial chain link material as EN 9. is studied via experimental result analysis and mathematical modeling. Outputs extracted from Taquchi Data Envelopment Analysis Ranking(DEAR) used for optimization of output parameters resulted with optimal solutions.

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    Keywords: ANOVA, Molybdenum Wire Electrode, Multi Response Characteristics, Optimization, Taquchi Data Envelopment Analysis, WEDM.

     

    Modelling and Control Design of a Magnetorheological Fluid Brake

    by Riccardo Russo, Mario Terzo

    Vol. 7. n. 3, pp.474-478

     

    Abstract - An experimental/theoretical activity concerning the modelling and the adaptive control design of a magnetorheological fluid brake is described. The parametric uncertainty that characterizes the system suggests the employment of an adaptive control finalized to track the reference braking torque. This feedback control method is able to minimize the tracking error in presence of a plant characterized by a known dynamics and uncertain parameters. Numerical simulations have been carried out and the obtained results confirm the goodness of the proposed approach.

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    Keywords: Mechatronic Systems, Magnetorheological Fluid Brake, Feedback Linearizing Control, Adaptive Control, Measurement Reduction.

     

    Numerical Simulation of Capillary Pump Evaporator Using Water for Different Inclination Angles

    by Nikolaos A. Avgerinos, Dionissios P. Margaris

    Vol. 7. n. 3, pp.479-486

     

    Abstract - A Capillary Pump Loop (CPL) is a two-phase heat transfer device considered a useful solution for thermal control applications in spacecrafts, satellites and electronic components. Purpose of this paper is to study aspects of the working state of the Capillary Pump Loop. A two dimensions computational model was designed to analyze heat transfer and liquid saturation inside the wick. Different cases were studied by changing the saturation temperature of the working fluid, water in our case, the heat load applied to the evaporator external wall, the wick heated length and the inclination angle to the horizontal level. Temperature flow results, inside the wick and at the evaporator exit, are presented, giving a better understanding of the function under several circumstances which enables more efficient evaporator design, capable to transfer bigger amounts of heat.

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    Keywords: Analytical Solution, Saturation Temperature, Wick Heated Length, Inclination Angle.

     

    Energy Saving in the Hydraulic Cylinders by Using Novel Self-Actuated Flow Control Valve (SAFCV)

    by M. Osman Abdalla, T. Nagarajan, Fakhruldin M. Hashim

    Vol. 7. n. 3, pp.487-494

     

    Abstract - Hydraulic power technologies often work continuously around the clock, handling large amounts of power in all kinds of Industrial and mobile machineries. Even little improvements in the efficiency of the power hydraulic systems will have an enormous amount of energy saving and a significant economic impact on the overall Lifecycle cost of the growing number of the hydraulic machineries. The study intended to propose fast and efficient power hydraulic actuators. The proposed hydraulic system involved a modification of the existing linear hydraulic cylinder by adding two new ports to it. A unique self-actuated flow control valve was also proposed so as to maintain the integration of the proposed four ports cylinder in the traditional hydraulic system and to preserve the controllability of the existing directional valves of the traditional system. The power and energy losses in the hydraulic cylinders were studied, discussed and analyzed. The results showed that at some high piston speeds as 0.22 m/s some of the conventional cylinders loss 9.2% of their driving power. The power loss at the same mentioned speed was reduced to 2.8% with the use of the proposed four-ports cylinders system. This means 6.4% of the system power was saved by adding two additional ports to the existing conventional hydraulic cylinder. Experimental validation of the results was performed and the performance of the proposed system was tested. The results of the experiments showed good agreement with those from the simulations.

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    Keywords: Computational Hydraulic, Energy Efficient Actuators, Energy Saving in Hydraulic High Speed Hydraulic Actuators, Hydraulic Control.

     

    Optimization of Surface Roughness in Wet Turning Operation of High Carbon High Chromium Steel

    by Rahul Davis, Mohamed Alazhari, Abdurahman HA Zubir

    Vol. 7. n. 3, pp.495-498

     

    Abstract - In order to control the required surface quality, generally it is vital to have the choice of optimized cutting factors in various industrial machining operations. The trait of surface finish is a vital concern for most of the turned parts in an industry. The present research work is focused on the optimization of cutting process parameters (depth of cut, feed rate, spindle speed) in wet turning of High Carbon High Chromium Steel (2.2% C) having hardness 50+2 HRC. Therefore turning operations were performed on High Carbon High Chromium Steel by carbide P-30 cutting tool in wet condition and the combination of the optimal levels of the parameters was obtained. Analysis of Variance (ANOVA) and SN (Signal-to-Noise) ratio were implemented to analyze the performance characteristics in wet turning operation. The results of the analysis show that none of the factors was found to be significant. Taguchi method showed that spindle speed contributed the highest effect on the surface roughness followed by depth of cut and feed rate while turning High Carbon High Chromium Steel by carbide cutting tool in wet turning. The useful results obtained by this research can be the eye openers for other similar type of future research works.

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    Keywords: High Carbon High Chromium Steel, Surface Roughness, Taguchi Method, Wet Turning.

     

    Tool-Life Model for Ceramics through Experimental Design in High Speed Machining (HSM) of 36NiCrMo16 Steel

    by S. Ben Salem

    Vol. 7. n. 3, pp.499-506

     

    Abstract - This paper describes a method for determining the life of cutting tools and ceramic when machining at high speed using the methodology of experimental design. The methodology is applied to determine the effect of cutting parameters on the tool’s life. Flank wear has been considered as the criteria for tool failure and the wear was measured using a Nikon measuring microscope. Further testing was stopped and the insert rejected when an average flank wear greater than 0.30 mm was reached. The exponential model was applied to determine the correlation between cutting time and the independent variables. The results indicated that the cutting speed Vc was a dominant factor on the tool’s life, followed by the criterion of flank wear VB * finally, the f and ap. The analysis of longitudinal monitoring of wear over time via the model (14) shows that the shape of the wear obeys the universal law of usury of any mechanical part.

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    Keywords: Tool-Life, Flank Wear, Ceramic Tools, High Speed Machining HSM, Experimental Design.

     

    Forces and Efficiency of Cams

    by F. I. Petrescu, R. V. Petrescu

    Vol. 7. n. 3, pp.507-511

     

    Abstract - The paper presents an original method to determine the efficiency of a mechanism with cam and follower. The originality of this method consists in eliminating the friction modulus. In this research it analyses four types of cam mechanisms: 1.The mechanism with rotary cam and plate translated follower; 2.The mechanism with rotary cam and translated follower with roll; 3.The mechanism with rotary cam and rocking-follower with roll; 4.The mechanism with rotary cam and plate rocking-follower. For every kind of cam and follower mechanism one uses a different method to determine the most efficient design. We take into account the cam’s mechanism (distribution mechanism), which is the second mechanism in internal-combustion engines. The optimizing of this mechanism (the distribution mechanism), can improve the functionality of the engine and may increase the comfort of the vehicle too.

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    Keywords: Cam, Efficiency, Translated Follower, Rocking-Follower, Follower with Roll.

     

    Improving Warpage on Thin Shallow Parts in Two-Plate Moulds with Conformal Cooling Channels

    by Z. Shayfull, M. S. Bahari, S. A. Adam, S. M. Nasir, Z. Nooraizedfiza

    Vol. 7. n. 3, pp.512-518

     

    Abstract - Nowadays, the trend of consumer products designed is getting smaller and most of cover is made from plastic which was produced by using injection molding process. Thus, the demand of thin shallow plastic parts in global industries is increasing today. In addition, manufacturing engineers have difficulties to control the parameters during processing the 1 mm thickness of the thin shallow parts where the warpage defect is the common issue especially for the thin parts. Therefore, this study is performed purposely to evaluate the performance of conformal cooling channels compared to the straight drilled cooling channels in order to minimize the warpage on the thin shallow parts. The type of gating systems used in this study is side gate, which is commonly gate in 2-plate mold. The results from simulation through Autodesk Moldflow Insight (AMI) 2013 are analyzed by using Taguchi Method and Analysis of Variance (ANOVA). Results from this study show that conformal cooling channels are able to improve the quality of the molded parts in term of warpage compared to the conventional straight drilled cooling channels. This is beneficial for the molding industries especially for the precise parts.

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    Keywords: Thin Shallow Shell, Taguchi, Analysis of Variance (ANOVA), Conformal Cooling Channels and Injection Molding.

     

    A Full Scale Motorcycle Dynamic Rig

    by D. De Falco, G. Di Massa, S, Pagano

    Vol. 7. n. 3, pp.519-526

     

    Abstract - Knowledge of “out of plane” modes is very important when defining the dynamic behavior of a motorcycle and its stability and handling in particular. Several mathematical models are available in the literature to study and preview frequency, damping and stability of these modes but, in order to verify these values, road tests must be performed which are sometimes dangerous for the tester. A test rig to evaluate the possibility of performing a dynamic characterization of the out of plane modes instead of road tests, was developed. The use of a test rig is certainly limited compared with road tests since the physical phenomena are not completely reproduced but allows tests to be extended to low and very high speeds and assures test repeatability. This paper presents the test rig and the results of an experimental investigation conducted on a scooter; the tests were conducted in steer free control condition with different inertia and tire characteristics.

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    Keywords: Motorcycle Dynamics, Test Rig, Wobble, Wave, Shimmy, Modal Anlisys.

     

    Castor Dynamic Investigation

    by D. De Falco, G. Di Massa, S. Pagano

    Vol. 7. n. 3, pp.527-533

     

    Abstract - Dynamic behaviour of vehicles having castored wheels can be affected by wheel shimmy phenomenon, that is a self-sustained vibration of the whole castor around the steering axis. This article presents a shimmy investigation conducted on a laboratory castor characterized by low lateral stiffness; numerical models show that this characteristics leads to three different stability conditions depending on the forward velocity: at low speeds the system is unstable and the castor is affected by shimmy oscillations; then there is an intermediate speed range in which the system recovers stability; finally, above a threshold speed value, the system returns to be unstable. The experimental investigation mainly aims to compare the numerical results with the experimental ones and to define the steering damping required to stabilize the castor according to its main features.

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    Keywords: Castor, Shimmy, Stability.

     

    Mechanisms for Renewable Ocean Energy Conversion

    by Diamantino Durão, Leão Rodrigues

    Vol. 7. n. 3, pp.534-540

     

    Abstract - Due to economic social cohesion, the European Union is promoting to improve the production of electrical energy from renewable energy sources. Ocean waves have associated a form of renewable energy which can be captured by using a hydro mechanical device that in turn drives an electrical generator to produce electrical energy. After a brief description of wave formation and quantifying the power across each meter of wave front associated to the wave, the paper describes the modern Pelamis system in some detail, and also oscillating column of water recently installed in Portugal. Ocean energy market is also discussed.

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    Keywords: Wave Power, Wave Formation, Some Ocean Energy Converters, Ocean Energy Market.

     

    CFD Simulation and Experimental Investigation of Convection Heat Transfer in a Rectangular Convergent Channel with Staggered Ribs

    by Sivakumar K., E. Natarajan, N. Kulasekharan

    Vol. 7. n. 3, pp.541-548

     

    Abstract - Forced convection heat transfer of air in a rectangular convergent channel with 90˚ ribs on bottom wall was investigated experimentally and numerically. The copper test section was inlet 100 mmx 80 mm x 5 mm and outlet 100 mm x 74 mm x 5 mm convergent rectangular channel with ribs were 3,6 and 9 mm square with 60 mm pitch distance for each 4 numbers of ribs were attached in the bottom surface of the test channel. The tests investigated the effect of air mass flow rate on the convection heat transfer enhancement with the above sized ribs. Comparisons between the experimental and numerical results showed that the RNG k−ε turbulence model. The numerical model was crated as per the same dimension of experimental test section channel size and three different sized ribs are mounted at the bottom surface of the test section. The experimental investigation and numerical analysis was conducted for the Reynolds number 20,000. From the experimental and numerical results indicate that the heat transfer coefficients for 6mm sized ribbed channel were largest among the three sized ribs.

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    Keywords: Rib Turbulators, Turbulent Flow, Heat Transfer, Friction Factor.

     

    Optimization of Wire-Winding and Shrink-Fit Combination in Pressure Vessel Reinforcement

    by A. H. Jabbari, M. Sedighi, A. M. Razeghi

    Vol. 7. n. 3, pp.549-555

     

    Abstract - In thick-walled pressure vessels design, combination of reinforcement techniques is preferred in comparison with their solo applications. Wire-winding and shrink fit are two common techniques which can be used in order to introduce beneficial compressive residual stress in the core of thick-walled pressure vessels. An optimized combination of these two techniques would lead to the integration of their advantages. The purpose of this paper is to optimize the design of a two-layered cylinder for maximum fatigue life expectancy under the combinations of wire-winding and shrink fit techniques. The layers thicknesses and radial interference of shrink fit are treated as design variables by considering different number of wire layers. The numerical optimization procedure known as the Simplex Search Method is employed to optimize the variables. Also, the fatigue life is calculated based on ASME code for high pressure vessel technology. The fatigue life was compared for different cases. The results show that by using proper combination, significant life enhancement can be achieved as high as 30 times in comparison with a wire-wound vessel. Also, it could reduce the required number of wire layers for a constant fatigue life by about 80%, which is very desirable due to difficulties of wire-winding process.

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    Keywords: Fatigue, Optimization, Pressure Vessel, Shrink fit, Wire-Winding.

     

    Boring Tool Chatter Suppression using Magneto-Rheological Fluid Damper through Regression Models

    by S. Balamurugan, T. Alwarsamy

    Vol. 7. n. 3, pp.556-562

     

    Abstract - Chatter is a problem of instability in the metal cutting process, especially in boring operation when the length of the hole to be bored is high. The phenomenon is characterized by violent vibrations, loud noise and poor quality of surface finish. Chatter causes a reduction of the life of the tool and affects the productivity by interfering with the normal functioning of the machining process. Many academic and industrial engineers reported the chatter suppression in turning operation; however, for boring operation, there is a lot of scope for studying the chatter suppression problem. This paper presents the use of magneto-rheological fluid for active chatter suppression through regression models. The vibration signals corresponding to different machining conditions were captured. The relevant features of the signals were extracted. The characterized magneto-rheological fluid was taken and regression models were built to suppress the tool chatter based on on-line vibration measurement. The models built in the study are linear regression model, support vector regression model and artificial neural network model. The regression model results are validated.

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    Keywords: Artificial Neural Networks, Boring Operation, Linear Regression, Support Vector Regression, Suppression Techniques, Tool Chatter.

     

    Cubic Interpolation Profile Method for Prediction of Thermal Fluid Flow through Porous Media

    by Nor Azwadi C. Sidik, Syahrullail B. Samion

    Vol. 7. n. 3, pp.563-569

     

    Abstract - In the present study, an alternative numerical scheme was proposed to predict the thermal fluid flow through porous media in differentially heated walls of a square enclosure. In the present study, the advection phase of the vorticity transport and stream function equations was solved using the cubic interpolation profile scheme while the conventional finite difference technique was applied for the non-advection phase. A low mesh resolution was applied in all the computations. The predicted streamlines, isotherms and the Nusselt number show excellent agreement with the previous studies. This demonstrates the efficiency and multidisciplinary applications of the proposed scheme.

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    Keywords: Natural Convection, Porous Media, Cubic Interpolation, Stream Function, Vorticity.

     

    Dynamic and Thermodynamic Analysis of Film-Cooling

    by Nor Azwadi Che Sidik, Ehsan Kianpour, Iman Golshokouh

    Vol. 7. n. 3, pp.570-577

     

    Abstract - This study was done to extend database knowledge about the film cooling action at the end of combustor and inlet of turbine. The well-known Brayton cycle plays a key role to get higher engine efficiency in gas turbine engines. But the high temperature of the combustor exit flow creates unpleasant environment. These surroundings lead to a reduction in the expected life of critical parts. There are two separate ways for Gas turbine cooling: internal cooling and external cooling. Film cooling is one of the most effective external cooling methods. In this system, a low temperature thin boundary layer such as buffer zone is formed and attached on the protected surface. In this study, a literature survey was done on the limited surveys that considered the effects of flow structure variations on film cooling, particularly from the first of 21th century.

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    Keywords: Gas Turbine Engine, Combustor, Film Cooling, Cooling Holes, Turbine Vanes.

     

    Stress Intensity Factors Under Mode III Loadings

    by A. E. Ismail, A. K. Ariffin, S. Abdullah, M. J. Ghazali

    Vol. 7. n. 3, pp.578-582

     

    Abstract - This study presents a numerical investigation on the stress intensity factors (SIF) obtained under pure torsion loadings or mode III. ANSYS finite element analysis (FEA) was used to determine the SIFs along the crack front of surface cracks embedded in the solid circular bars. 20-node isoparametric singular elements were used around the crack tip by shifting the mid-side node ¼-position close to a crack tip. Different crack aspect ratio, a/b were used ranging between 0.0 to 1.2 and relative crack depth, a/D were ranged between 0.1 to 0.6. Mode I SIF, KI obtained under bending moment was used to validate the proposed model and it was assumed that this proposed model was validated for analyzing mode III problems. It was found that, the FII and FIII were dependent on the crack geometries and the behavior of crack growth were also dependent on a/b and a/D.

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    Keywords: Stress Intensity Factors, Mode III, Surface Crack, Finite Element Analysis.

     







 
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