|
|
|
|
Home>Products>Journal and Reviews>I.RE.M.E.>Latest issue
International Review of Mechanical Engineering - January 2010 - Papers
International Review of Mechanical Engineering - Papers
Vol. 4. n. 1, pp. 1-6
Abstract - Surface treatment of the silk fibre by silane coupling agent in order to improve the interfacial strength between silk fibre and epoxy resin has been carried out. Woven silk fibre/epoxy composites have been fabricated to determine the interlaminar fracture toughness of the specimen at different number of fibre plies. The processing technique used to prepare the sample is by a vacuum bagging process and the curing process was carried out in an autoclave. In this study, specimens were fabricated by using silk fibre of between 8 to 14 plies for each panel. First set of composites panel consisted of raw silk fibre while the second sets consisted of silk fibre which has undergone a surface treatment using 3-aminopropyl triethoxysilane coupling agent. Mode I interlaminar fracture test is based on double cantilever beam specimens (DCB) testing method. The results of the GIC were plotted and compared between the two sets. GIC of the composite in set 2 were found to be higher than the value in set 1. During the test, crack propagation is stable and no fibre bridging occurred between both sides of fracture surfaces. All the failure that occurred were at the fibre-matrix interface as seen using SEM. The results shows that fibre surface treatment of silk plies will increases value of GIC. This proved that the GIC of woven silk fibre/epoxy composites can be enhanced by surface treatment using 3-aminopropyl triethoxysilane coupling agent. The results give an improvement of interlaminar fracture toughness between 2.3 – 10.6 % at initiation and 5.5 – 9.2 % at propagation. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Polymer composites, Adhesion, Scanning electron microscopy, Surface morphology.
Vol. 4. n. 1, pp. 7-11
Abstract - Many earlier studies have suggested that powder metallurgy process applied to high speed steels improve wear resistance. This paper investigates the effects of manufacturing process according to the heat treatment on wear behaviour of AISI M4 high speed steel that profited from this rather recent technique: Powder Metallurgy. In a first step heat treatment characteristics were optimised by austenitizing for hardening and tempering and then pin-on-flat wear experiments were done on both the conventional and the powder metallurgy material. We found that wear resistance is influenced by heat treatment in a same way as hardness. In addition the wear resistances of both steel are very close and at least; the effect of the small size and uniform carbide distribution produced by powder metallurgy process on the wear resistance is evidently overestimated. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Wear resistance, High speed steels, AISI M4, Heat treatment, Carbides.
Vol. 4. n. 1, pp. 12-17
Abstract - In this study the effect of particulate reinforcement addition to latent heat generation and solid fraction during solidification of metal matrix composite is investigated. Vortex mixing - sand casting technique is employed to produce the specimens. Solidification data during the casting process is acquired and studied using Fourier thermal analysis (FTA) to calculate the latent heat generation and solid fraction. In this study latent heat and fraction solid are obtained by performing calculations based on FTA. The results show that when volume fraction of particulate reinforcement is increased, the fraction solid rate is faster and the latent heat generation during solidification decreased. It is concluded that as more particulate reinforcement is added, it promotes faster solidification during the casting process. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved Keywords: Metal matrix composite, Fourier thermal analysis, Latent heat, Solid fraction.
Vol. 4. n. 1, pp. 18-27
Abstract - There are many situations in which composite structures are subject to collisions or impacts whose intensity produces damages and perforations. Models for the behavior of the impact have been proposed in a number of past studies. However, these models which were developed for specific cases cannot be used in case of an elastic-plastic of a structure whose properties are linearized. The present study is devoted to analyzing the behavior during a shock of stratified composite plates. It includes:The study of the Hertz law as modified by Yang S.H and Sun to describe the motion of a stratified composite plate subjected to a low velocity shock.The use of an iterative method for the solution of the non-linear equation of penetration.The determination of the force of contact and of penetration. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Composite, Impact, Models for the behavior, Failure load.
Vol. 4. n. 1, pp. 28-34
Abstract - Keeping in mind a range of industrial applications, the performance of Al-Si alloy reinforced with ceramics as a metal matrix composites manufactured using Stir casting technique have been investigated. Aluminum-Silicon alloys of near eutectic composition (12% Silicon by weight) and Hypereutectic (17% Silicon by weight) were the matrix materials used. The two matrix materials were processed under identical conditions using two different reinforcements Silicon Carbide (SiCP) and Aluminium Oxide (Al2O3P) in particulate form with 0, 5, 7.5 & 10 Vol% .Wear and friction coefficients were determined from dry sliding wear tests of cast Particle Reinforced Metal Matrix Composites( PMMC’s) at 20, 40, 60 N test loads and at 1.42 & 2.22m/s sliding velocities. Cutting forces exerted and Surface Roughness (Ra) produced during machining of cast PMMC’s with Polycrystalline Diamond (PCD) and K10 cutting inserts at 75 m/min & 118 m/min cutting speed were studied. Wear of Al2O3P reinforced alloys was around 20% higher than SiCP reinforced alloys. PCD cutting insert seems appropriate in machining Al-Si alloy composites needing lesser cutting force and producing better surface finish. . Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Al-Si alloy composites, SiCP, Al2O3P, Dry sliding wear, Cutting force, PCD, K10.
Vol. 4. n. 1, pp. 35-41
Abstract -
This article presents the development of a law of visco-elastic behaviour
with one-sided damage for the bituminous materials, based on the
observation of the essays of direct break on film of asphalt between two
hemispheres of metal. The essays of fatigue of the bituminous materials
realized on test tubes lead a loss of rigidity combined in a significant
extension of test tubes at the beginning of the essay for strong levels
of solicitation. It will also present a structure design of the asphalt
pavement in Japan.
Keywords: Binding hydro-carbonned, Asphalt pavement, Visco elastic, Fatigue life, Microcracks, Law of behaviour, Rutting, Numerical simulation.
Vol. 4. n. 1, pp. 42-50
Abstract -
In this paper, the friction aided deep drawing using tapered blank holder
divided into four and eight segments is studied. Several parameters
including effect of blank holder force, radial displacement of blank
holder and punch force on cup height are investigated in the four
segments tapered blank holder technique. The drawing mechanism and the
effects of drawing conditions are also studied using ABAQUS/explicit
software to show the merits of the process. Using the four segments type
may cause a non-uniform flow of material in the flange portion; however,
the eight segments type can overcome this deficiency. Therefore, the
drawing mechanism of eight segments tapered blank holder technique and
in-flow of material in the flange portion of blank are mainly
investigated and compared with those from four segments tapered blank
holder. A successful deep cup of drawing ratio 3.67 can be produced
without any defect by using eight segments tapered blank holder
technique. The cost and time of die fabrication in these techniques are
less than the conventional deep drawing.
Keywords: ABAQUS /Explicit, Friction Aided Deep Drawing, Tapered Blank Holder.
Vol. 4. n. 1, pp. 51-59
Abstract -
Turbulence schemes have long been developed and examined for their
accuracy and stability in variety of environments. While many flows work
with disturbed turbulence intensity, models have rarely been tested to
explore whether their accuracy withstands to augmented free stream
turbulence intensity or declines to an erroneous solution. In present
study turbulent intensity of flow stream of air, moving parallel to a
flat plate, is augmented by means of locating a grid screen at a point
at which Rex=2.5×105 and effect on downstream is studied. Depending on
grid sizing, turbulent intensity is augmented from 0.4% to 6.6% for the
whole flow at this cross section. Wind tunnel measurements provide the
effect on downstream variables including velocity fluctuations in main
stream and near the wall. Numerically, four most popular turbulence
models are examined for similar physical case by more attention on
turbulence penetration into flow field as well as into turbulent
boundary layer of the flat plate. Numerical solutions of one equation
Spalart-Almaras, two equations high Reynolds number k-ε, two equations
Shear Stress Transport k- Ω and anisotropy Reynolds Stress Models are
compared to experimental measurements and results are discussed.
Conclusion is made that despite accuracy these turbulence models
believed to have, even in some difficult flow fields, they may fail to
handle high intensity turbulent flows.
Keywords: Free stream turbulence, Turbulence intensity, Turbulence models, Turbulence penetration.
Vol. 4. n. 1, pp. 60-64
Abstract -
In this work, we present a numerical study to determine a heat source
density, homogeneous in a domain. We show how a point source
"equivalent" to approach the phenomenon. The method is based on a
technique of inversion of a convolution integral, and secondly, on a
direct modeling of the system by finite differences. This inverse
problem has two steps to locate the position of this source, then an
identification of its amplitude as a function of time, we notice that we
have a good result for the location, whilst the intensity of the source
volume we have a worse outcome, because we identified a point source is
equivalent to an approximate solution.
Keywords: Heat source, Inverse method, Convolution integral, Finite differences.
Vol. 4. n. 1, pp. 65-70
Abstract - The aim of the present paper is to present an experimental method for the prediction of slug-churn transition in two-phase flow. Some hundreds of measured points for both 40 mm and 28 mm of upriser internal diameter are recorded, all of them being experimental data of the Fluid Mechanics Laboratory of the Patras University. The theoretical part of the method follows, which is believed to be the main part of the whole analysis. The drift-flux model is applied to all experimental data and drift velocity curves are drawn. The slope of one drift-flux parameter seems to present local low points (dips). An investigation of these points follows in the final step which is the validation of the proposed method. The measured and thus calculated points, presented upon previously introduced regime maps, seem to be quite close to the regime transition line. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Fluid Mechanics, Multiphase Flow, Voidage, Drift-flux Model, Air-lift Pump, Two-phase flow, Regime map, Slug-churn transition.
Vol. 4. n. 1, pp. 71-79
Abstract - This article is focused on the development of a finite element model for capturing the fluid-structure interactions in a hybrid electro-hydraulic pump system. The system under study consists of a piezo-actuated piston and two passive poppet valves. A Finite Element Model has been developed which simulates the oscillatory fluid motion (compressible Navier–Stokes equations with standard k-e turbulence extensions) and incorporates an Arbitrary Lagrangian–Eulerian formulation to allow a deforming moving mesh. Through this moving mesh the fluid is capable of tracking the motion of the piston and valves, while a two-way interaction is applied to the surrounding rigid structure. The fluid pressure profile surrounding the solid regions is applied as a force load to the solid and the solid motion is transferred to the fluid domain as a mesh deformation. The simulation results offer useful insight on the pump’s performance caused by changes in the: a) valves’ spring stiffness and mass, and b) piston’s operating frequency. A careful parametric optimization on certain pump’s parameters yields a twofold increase in its performance at high frequencies (500 Hz). Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Poppet valve, High Frequency pump, Finite Element Model, Optimization.
Vol. 4. n. 1, pp. 80-84
Abstract - Hermetic compressor is the main component in small capacity refrigeration systems. The performance of such system is normally dependent on the discharge port area in the valve plate. This research paper presents an estimation of optimum Mach number for port areas of hermetic compressor model suitable for water cooled system with R-22 refrigerant so that it can be used for one TR air conditioning application using R-410A refrigerant blend. Making use of geometric data available with the existing model i.e., total suction and discharge port areas the corresponding Mach numbers are established for the fixed mass flow rate of 0.02 kg/sec with the refrigerant R-22. Based on the values of Mach numbers ranging from 0.0005 to 0.20 at suction and discharge sides, suction and discharge port areas the valve plate for the model are tabulated both for R-22 and R-410A refrigerants. For optimum compressor performance the optimum Mach number for port areas for the compressor model suitable for refrigerant blend R-410A is included. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Hermetic compressor, Valve plate, R-410A, R-22, Mach number.
Vol. 4. n. 1, pp. 85-91
Abstract - This paper aims at showing how the constructal theory can be applied to the optimization of mechanisms and machine elements. First of all, the concept of mechanism skeleton needs to be introduced. In this work, the constructal theory is based on a single principle, i.e. the minimization of energies in connections, which allows us to optimize the topology of this skeleton. In this first stage, it is also possible to determine equivalent inertias for each bar. Then, in a second stage, this paper deals with the stage of shape optimization of the various machine elements. During these two stages, optimization is carried out by genetic algorithms. This paper also shows that the sole objective of minimization of energy is not enough if the constructal theory is to be applied to obtain optimal shapes. It is obvious that this theory needs to be associated with other objectives or constraints of optimization. To summarize, this paper only offers a first feasibility study of the constructal theory for the optimization of mechanical structures. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Constructal design, Mechanisms, Shape optimization, Genetic algorithms.
by A. Shahrjerdi, M. Bayat, F. Mustapha, S. M. Sapuan, R. Zahari Vol. 4. n. 1, pp. 92-105
Abstract - The theoretical equation of bending analysis of functionally graded (FG) quadrangle plates based on second order shear deformation theory (SSDT) are presented. Full-ceramic at upper surface material and full-metal at lower surface is considered and material properties between upper and lower surface are assumed to be graded by a power law distribution in terms of the volume fractions of the constituents. The complete form of governing equations are derived by the energy method and then solved analytically by applying Navier's method to obtain the displacement and stress components. The results are given under four types of mechanical loading for a quadrangle plate with simply supported boundary conditions. The effects of the material grading index of the plate on the stresses and displacements are thoroughly investigated. The mechanical responses of homogeneous and FG plates are compared and verified with the known results in the literature. It is found that the neutral axes for FG plates move to upper surface (full-ceramic) and not at the mid-surface as predicted in the homogeneous plates. It can be concluded that, the gradation of the metal–ceramic components of the plate is the significant parameter in evaluating the mechanical responses of the FG plate. The SSDT has computed acceptable results for in-plane stresses and displacement fields. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Functionally graded material, Second Order Shear Deformation, Stress analysis, Quadrangle plate.
Vol. 4. n. 1, pp. 106-111
Abstract - The proposed engineering system concept, SharE, is intended to overcome major impediments to electric vehicle (EV) adoption, including great anxiety of consumers concerning reduced EV autonomy and the absence of interest of major players in the development of EVs. The system presented supports fast exchange of batteries, which requires minimal equipment in the battery exchange station, favouring expedited early adoption of the EV system. The human interface of equipment was designed to meet ergonomic requirements. Even though only minimum equipment is necessary for road-side battery exchange, added convenience and speed of battery replacement can be accomplished with more sophisticated equipment, installed in exchange stations. The EV proposed has additional standard plug-in capacity. It is based on an innovative concept of ownership, since the battery system is to be owned by organizations that are to offer the road-side battery exchange service. Aerodynamics were considered in the vehicle’s design, which, utilizing commercially available batteries and electric motor, is expected to attain a 220km autonomy, at an average speed of 90 km/h. The paper lists the most important engineering problems that must be addressed in the engineering design of the proposed system concept and of future EVs. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Exchangeable battery modules, Vehicle archetype, New system concept, Sustainable transportation.
Vol. 4. n. 1, pp. 112-119
Abstract - This paper presents a formulation for in-plane modal characteristics of non-uniform thickness annular elliptic and circular plates for all classical boundary conditions. The investigations are performed for elastic and isotropic annular elliptic plates on the basis of two-dimensional linear plane stress theory of elasticity. Two-dimensional boundary characteristic orthogonal polynomials (BCOP) are used in the Rayleigh-Ritz method to obtain the natural frequencies and associated mode shapes. The proposed method, not only can find solution for those simple cases of annular circular plates available in literature as a simplified case study, but also it finds some natural frequencies which can not be determined by using one dimensional BCOPs. Finally the results of present method have been compared with those of finite element analysis carried out in this research. Good agreement has been observed and reported. Copyright © 2010 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: In Plane Free Vibration, Elliptical Plate, Rayleigh-Ritz, Non-Uniform Thickness.
|
|
Please send any questions about this web site
to
info@praiseworthyprize.com
|
