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Home>Products>Journal and Reviews>I.RE.M.E.>Latest issue
International Review of Mechanical Engineering - January 2009 - Papers
International Review of Mechanical Engineering - Papers
Vol. 3. n. 1, pp. 1-6
Abstract - In this paper we attempt to study the influence of the compliant joints on the dynamic behaviour of the multilink guiding system used for the rear axle of the commercial vehicles. In fact, we are interested to determine the differences between the compliant model (with bushings) and the rigid model (bushings modelled as spherical joints) of the guiding axle linkage. The idea is to establish if the rigid model assumption is useful (or not) in the dynamic analysis of the axle guiding linkage. The comparative analysis is made considering the general case of guidance of the rear axle, namely the guiding mechanism by five points, with four longitudinal guiding arms, and one transversal arm (Panhard arm). The main parameters used in the comparative analysis refer to the vertical displacement of the car body, the roll and the pitch oscillations, as well as the specific linear & angular accelerations The study is performed by developing the virtual prototype of the rear axle, which is a half-car model, using the MBS software ADAMS/View(MSC Software). Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Rear Axle, Guiding Mechanism, Dynamics, Multibody System.
Vol. 3. n. 1, pp. 7-15
Abstract - The cognition of the effect of cutout on the capacity of loading bearing and the buckling behavior of the cylindrical shells is crucial in designing of structures of automobiles, airplanes and marine structures. In this article, the simulation and analyzing of steel cylindrical shells with different lengths and diameters, including elliptical cutout, under bending moment with using of the numerical finite elements method was done. Furthermore, the effect of changing of cutout dimensions and the ratio of the length to diameter on buckling behavior and post buckling of cylindrical shells are studied. Finally, the relations for finding of buckling moment of these structures were presented. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved Keywords: Buckling, Steel cylindrical shells, Elliptical cutout, Bending moment, Finite element method.
Vol. 3. n. 1, pp. 16-21
Abstract - In this paper, the weight functions for deep and superficial points of semi elliptical crack, situated in pipes internal surface are achieved. Coefficients of tension intensity are introduced into closed solution, using the achieved weight functions for two parabolic pressure loading position on the crack surface and pipe with internal pressure. In order to modeling the linear semi elliptical crack situated in internal surface of thin-walled pipe, three-dimensional finite elements method has been used. The weight function for deep and corner points of semi elliptical crack has been achieved. For computing the coefficients of tension intensity quantities we have used the extrapolate displacement method. Results have been compared with the finite element method, which show good results. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Crack, Finite elements model, Tension Intensity.
Vol. 3. n. 1, pp. 22-28
Abstract -
In this
study, an analysis has performed for heat and mass transfer of a MHD
fluid of second grade subject to suction and to a transverse uniform
magnetic field past a thermal forming stretching sheet with Ohmic
dissipation through a Porous Space. Parameters Gr, Gc, M, DL and Sc
which are used to represent the dominance of the buoyant effect,
magnetic effect, porosity effect and mass transfer effect are present in
governing equations, respectively. The similar transformation and the
finite-difference method are used to analyze the present problem. The
magnetic parameter and porosity parameter may reduce the heat transfer
effect. On the other hand, for mass transfer, the value of Sc parameter
is important factor in this study. It will produce greater heat transfer
effect with a larger value of Sc.
Keywords: Heat and mass transfer, MHD, Second-grade fluid, Stretching sheet, Ohmic dissipation, Porous space.
by Uttam K. Chakravarty Vol. 3. n. 1, pp. 29-38
Abstract - A new Delaunay refinement algorithm is developed for free mesh generation inside both convex and non-convex hulls for integrating core materials within the cavities of composite rotor blade cross-sections. After defining the geometry and material properties of the cross-section, meshes are generated for finite element analysis. Finite element analysis is considered for computing sectional properties and stress distributions over the cross-section. It is found that this free mesh generation algorithm can produce fine meshes for computing convergent sectional properties of composite rotor blade cross-sections with core materials. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Mesh generation, Delaunay refinement algorithm, Composite rotor blade cross-sections, Core materials, Finite element analysis (FEA), Sectional properties.
by M.D. Anwarul Hasan, Amkee Kim Vol. 3. n. 1, pp. 39-47
Abstract - Al-Si-Cu-Mg alloy foams of different compositions and different cell morphologies were produced using the powder metallurgical method and by varying the foaming time and temperature during production. Hardness of the produced precursors and foams was measured using nanoindentation and micro indentation hardness measurement methods. Results obtained from both of the methods showed similar trend although the nanoindentation hardness of the specimens was consistently higher than the corresponding micro Vickers hardness. The precursor and foams obtained from Al-5wt.%Si-4wt.%Cu-4wt.%Mg (alloy 544) showed a higher hardness value than Al-3wt.%Si-2wt.%Cu-2wt.%Mg (alloy 322) precursor and foams made at the same foaming temperature and time because of their higher content of alloying elements. The hardness value of foam walls increased with the increase in foaming time at all foaming temperatures due to the increase of eutectic phase. Same density foams obtained from the same precursor but at different foaming temperatures were found to have different hardness values which indicate that local and global properties of foams with similar densities obtained from the same precursor will differ from each other if their foaming conditions are not the same. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords: Aluminum foam, Hardness, Microstructure, Powder Metallurgy, Nanoindentation.
Vol. 3. n. 1, pp. 48-57
Abstract - “Cold Combustion” modes are controlled by mixing prior to injection and, therefore, accurate description of the physical phenomena occurring within the intake port (e.g., atomization, spray-wall impingement and mixing) is crucial to further simulate the energy release. Therefore, the accurate modeling of spray/wall interaction processes, including the hydrodynamic mechanisms of drop impact and the heat exchanges between the fuel spray and the heated wall, require the development of correlations built upon measurements of droplets size, velocity and fluxes, simultaneously with measurements of the surface thermal behavior. Most correlations developed for IC engine simulations do not consider the spray dynamic behavior in each injection cycle. Therefore, the present work briefly reviews the conventional method of devising heat transfer correlations for spray impingement. Afterwards, an experimental investigation is performed and the characteristics of the spray dynamics are analyzed in order to suggest a new approach in the development of heat transfer correlations for the impingement of fuel intermittent sprays, typical of port-fuel injection systems. The dynamic heat transfer correlation derived is further compared with one derived using a conventional approach and the results show an improvement of heat transfer predictions if the spray dynamic nature is taken into account. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Cold
combustion, Heat transfer, Port-fuel injection, Spray dynamics.
Vol. 3. n. 1, pp. 58-63 Abstract -
In polluted
environments such as Sahara, careers and mines, the wear of moving
mechanical parts is a real problem. In fact, when the sand particles are
very fine they pass through the filters and contaminate the lubricant
therefore, decreasing considerably the life time of the lubricated
mechanisms. The purpose of this work is to study the effect of the sand
as external pollutant on the lubricant and the wear of surfaces in
contact with this lubricant. In order to model the behavior of the grain
sand an experimental set up was carried out to simulate the contact.
This contact is made between two tangent cylinders, one driving
(sample), and the other, carried out (bearing). The pollutant is
filtered sand mixed with a lubricant then introduced into the
convergent. Two samples were used in our experiments: A60 mild steel and
XC55 relatively hard steel. The load parameters and bearing speeds are
controlled. The behavior of sand grains in the convergent is studied and
the analysis of the lubricant and the samples wear are carried out
according to the number of cycles required. The results showed that
during the first introduction in the convergent of contact the sand
grains have an oval form and are relatively thick, they explode,
fragment and become smaller, angular and present sharp edges
accentuating wear by abrasion. It is also noticed that the viscosity of
the lubricant varies and increases with the number of cycle when
measurement is instantaneous whereas it decreases when more time is left
for pollutants to elutriate. Finally, it is observed that a very
significant wear during the first cycles and deceasing as the number of
cycles increases as well as the appearance of the micro fatigue of
surfaces at the starting operating hours. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Lubricant,
Sand, Viscosity, Wear, Mechanical contact, Behavior.
Vol. 3. n. 1, pp. 64-73 Abstract -
In this paper
we developed a mathematical model to simulate drying of a ceramic porous
particle with superheated steam, humid air and dry air. This model is
based on the averaging approach taking into account the effect of
gradients of temperature, moisture content and pressure. When comparing
drying curves with superheated steam and dry air, a temperature at which
the evaporation rates within superheated steam and dry air are equal was
found. This temperature is called inversion temperature, above which the
evaporation rate in pure superheated steam is higher than in dry air.
This temperature was calculated during the constant drying rate. We
focused this study to examine the effect of the humidity, the pressure
and the mass flux of the drying agent on the evaporation rate, for
different drying conditions and for the inlet temperature. The
calculations results of the inversion temperature are in conformity with
the theoretical values from the literature. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Drying, Humid
air, Superheated steam, Inversion temperature, Porous particle.
by F. Zeroual Née
dadouche, L. Belabed, A. Zennir
Vol. 3. n. 1, pp. 74-78 Abstract
-
The slips of
lands entail important messes with serious consequences on goods and
people. Several methods treat the phenomenon of slip as for always
adopting the empiric global margins of safety, what often gives the
overdimentioned constructions and the enormous risks, for this a
reliable and realistic modeling is hoped by the suggestion of a new
mechanical model of rupture based on the kinematic method of the solid
rigid and the principle of the minimal security. A critical rupture
model will be suggested while adopting the new statistico -
probabilistic concept that constitutes a very useful comparison tool
because it takes into account the unpredictable scattering of the
different parameters (geometry, intrinsic features of soil, load, etc…).
The introduction of the concept of the reliability indication in
géotechnical constitutes a precious tool susceptible to confer to the
engineer a bigger objectivity in the conception of the banks. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Banks,
Failure, Probability kinematic of rigid solid, Fiability, Slide. by F.
Bouchelghoum, N. Benmebarek
Vol. 3. n. 1, pp. 79-90 Abstract
-
The intensive
use of urban subsoil and the evolution of technical regulations require
to develop new tools to calculate the displacements caused by the
construction of new structures. The performance of usual calculation
methods is often inadequate, because they have been developed mainly for
the analysis of the failure behaviour of structures; thus in these
models, the soil behaviour for small strains is not represented in a
realistic manner. The soil shear modulus exhibits significant variations
between the field of very small strains and the field of usual
deformations next to geotechnical structures during their construction.
Experience shows that the displacements of a structure can not be
correctly evaluated without taking into account these variations. In
this context, a Mohr-Coulomb model has been implemented in Flac2D code
in explicit finite difference method to calculate real structure for
which soil data as well as displacements and efforts measurements were
available. The study of this case confirms the interest of using a
Mohr-Coulomb constitutive law to produce calculation results similar to
the strain and displacement patterns of real structures. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Soil/Wall
interaction, Numerical modelling, Sheet pile wall, Flac2D, Small strains.
Vol. 3. n. 1, pp. 91-99 Abstract
-
The
prediction of the dynamic response of the bridges which results from the
passage of loads moving along the spans is a significant problem in the
field of the analysis and the design of the bridges. The dynamic loads
crossing the bridges at normal speeds cause more significant constraints
than those induced by vehicles which remain in a static position. The
goal of this work is to develop a digital model which, as much as
possible, approaches the reality of the dynamic analysis under moving
loads. This paper, firstly, reviews the literature of the impact of
loading on bridges; then we start the study by a modeling of the
equations governing the dynamic behavior of the bridges under the effect
of moving loads based on Lagrange formulation and the modal analysis.
The resolution of the dynamic equations is done using the integral of
Duhamel. The bridge is modelized by a beam with only one span and the
vehicles by point and periodic loads. A parametric study is performed to
identify the effects of various parameters on the dynamic load and
consequently on the DAF of the bridge, such as vehicle speed, spacing
between the vehicles, road surface roughness, the rigidity of the
bridge, the length of the span, etc. Lastly, we give some
recommendations, of which the resistance of the bridges to the dynamic
effects and the establishment of a dynamic factor of amplification
adapted to the specific conditions of loading of bridges. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Dynamics of
bridges; Moving load; Simple beam; Harmonic load; convoy of loads;
Vibration; Critical speed; Dynamic Amplification Factor (DAF).
Vol. 3. n. 1, pp. 100-103 Abstract
-
In this work,
we study by an experimental approach the effect of corrosion on the
behaviour dynamic of the reinforced concrete structures by measurement
of the Eigen frequencies. This test was applied on reinforced concrete
beams healthy and corroded subjected to a vibratory mechanical
excitation. For these tests we made use of a vibrating pot and a signal
analyzer. The spectral response of each beam gives information in the
form of signal which allows the measurement of these Eigen frequencies
so that one can determine the effect of corrosion on the behaviour
dynamic of the beam which represents the originality of our experimental
approach. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Vibration,
Accelerometer, Corrosion, Composite, Reinforced beam.
Vol. 3. n. 1, pp. 104-109 Abstract
-
The measuring
of the quantities of gas is a significant activity of the industry of
the transport of gas by drain, as well in the contractual or commercial
field as in the technical field where it makes it possible to give
essential information for the design of the gas networks. The purpose of
this study is essential, after a short recall on the methods of
calculation of the factor of compressibility and the flow according to
various standards, to give the importance necessary to carry out an
adequate choice of the method of calculation of these parameters. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Factor of
compressibility, Coefficient of discharge, Flow measurement, Gas
counting.
Vol. 3. n. 1, pp. 110-125 Abstract
-
Droplet size
distribution measurement of a two-phase, two-component spray is an
intricate process. This type of spray is three-dimensional in nature;
therefore multi-dimensional flow field measurement of the spray is
indispensable. Particle Dynamic Analyzer has been used for spray
characteristic measurements issuing from a wide variety of nozzles.
However, a reliable method for the calibration of the droplet size and
velocity measurements is required to ensure an unbiased measurement. The
application of the is still a challenge in highly concentrated
multiphase spray. In this paper, a detailed review of the advanced
experimental techniques and basic theory of two-phase, two-component
sprays is discussed. Special emphasis has been given to the Particle
Dynamic Analyzer systems and digital image analysis measurement
techniques. There are several studies found in the literature, which
explain the fundamental characteristics of turbulent jets and sprays.
However, limited studies can be found related to two-phase,
two-component horizontal flow sprays. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Two-phase
flow, Spray, Atomization, Advanced measurement techniques,
Particle-dynamic-analyzer.
Vol. 3. n. 1, pp. 126-132 Abstract
-
Amongst
different sources of renewable energy, biomass holds special promise due
to the inherent capability to store solar energy and amenability to
subsequent conversion into solid, liquid, and gaseous fuels. Biomass can
be utilized for various purposes through different conversion processes.
The potential offered by biomass to reduce greenhouse gas production is
now being more widely recognized. Gasification concentrated on woody
biomass with large energy production has been identified. In the present
work, a 200kWe down draft gasifier is used to investigate the potential
of selected woody biomasses such as Juliflora and Eucalyptus. The
proximate analysis of the biomasses is done, and calorific value and
composition of the product gas are obtained. Pressure drops are measured
across the gasifier and the gas cleaning system because the output of
the gas is directly utilized for power generation in the engine when it
is important to have the low pressure drop in the system. As the quality
of the system depends on the producer gas quality proper cleaning and
cooling of gas are to be ensured. The gas flow at full rating is
700-750Nm3/h and gasifier pressure drop is in the range of 20-22mm of
H2O. It is suggested that for rural and remote village electrification
the small scale gasifiers can be a good alternative choice. Copyright © 2009 Praise Worthy Prize S.r.l. -
All rights reserved Keywords:
Biomass,
Gasification, Characteristics, Downdraft gasifier. |
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