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Handling Analysis of a Light Commercial
Vehicle Considering the Frame Flexibility, by M. M. da Silva, Á.
Costa Neto
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Method for the Optimal Synthesis of the Wheel
Guiding Linkages of the Motor Vehicles, by C. Alexandru
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Adaptive Neuro-fuzzy Control With Fast
Learning Algorithm of PUMA560 Robot Manipulator, by R. Mellah,
R. Toumi
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Estimation of the Non-linear Limit Cycles of
Autonomous Mechanical Systems Based on a Constrained Non-linear
Approach, by B. Hervé, J.-J. Sinou, H. Mahé, L. Jézéquel
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An Efficient Algorithm for Computing n-Finger
Force-Closure Grasps for Planar Objects, by B. Bounab, D. Sidobre,
A. Zaatri
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Deformations in Round-Profiled Threads and their Influence on the
Screw Durability, by I. Penkov, V. Strizhak, A. Sivitski
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Validation of Available Approaches for
Numerical Bird Strike Modeling Tools, by M.-A. Lavoie, A. Gakwaya,
M. Nejad Ensan, D. G. Zimcik
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Static and Fatigue Characterization of Nomex
Honeycomb Sandwich Panels, by B. Keskes, A. Abbadi, Z. Azari, N.
Bouaouadja
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Effect of Different Rolling Schedules on the
Mechanical Properties and Microstructure of C Mn (V-Nb-Ti) Pipeline
Steel, by A. Guedri, D. Berdjane, S.Tlili, B. Merzoug, A. Zeghloul
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Continuum Based Solid–Shell Element Modeling
for the Optimization of Composite Multilayered Structures, by M.
Hannachi, H. Naceur, J. L. Batoz
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Mechanical and Tribological Characterization
of an Alloy of Surface Fe-Cr Formed by Laser Remelting and the
Effect of the Heat Treatment on the TTS, by H. Boudoukha, S. Djabi,
B. Coquillet
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Analysis of the Thermal Behavior of a
Ventilated Disc Brake, by M. Kaffel, H. Kchaou, M. Baccar
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Parametric Study of the Salt Gradient Pond
Stability, by F. H. Shehadi, A. Ben Moussa, M. Mseddi, M. Baccar
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Air Flow Patterns and Thermal Behavior in
“King Tutankhamen Tomb", by E. E. Khalil
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Innovative Use of Thermoelectricity for
Nuclear Waste: Modeling, Estimation and Optimization, by M. Lazard,
H. Catalette, L. Lelait, H. Scherrer
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International Review of
Mechanical Engineering - Papers
Handling Analysis of a Light Commercial Vehicle Considering the Frame
Flexibility
by M. M. da Silva, Á. Costa Neto
Abstract
- This paper presents a complete multibody model of a light commercial truck
considering the frame flexibility for handling characteristics studies. The
flexible multibody model was developed using a multibody package, and it
includes a complete primary suspension, the steering system, the power train, a
tire model (Delft) and the flexible frame. The directional response behaviour,
the drivability and the vehicle/road interaction are the factors that define
vehicle handling performance. The most important parameters concerning lateral
behaviour are: longitudinal velocity, tire cornering stiffness, suspension
system elasticity, steering systems elasticity, lateral load transfer, mass
centre location and aerodynamics properties. Consequently, regarding lateral
load transfer, the use of a flexible frame is very important. The complete model
was validated with experimental results and for the purpose of vehicle analyses,
typical standard handling manoeuvres were undertaken including constant radius
turn, constant velocity turn and double lane change. The results obtained were
lateral acceleration, yaw rate, side slip angle, roll angle and the understeer
gradient. Analysing the results, the vehicle showed a changing behaviour
concerning steer. At low velocities and lateral accelerations, the vehicle is
slightly understeer. However, at higher velocities and lateral accelerations, it
can become oversteer.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
lateral vehicle dynamics, multibody systems, finite element method, and virtual
prototyping.
Method for the Optimal Synthesis of the Wheel Guiding Linkages of the Motor
Vehicles
by C. Alexandru
Abstract
- In this paper, an analytical method for optimal geometric synthesis of the
spatial linkages used for the guidance of the rear wheels of passenger cars is
presented. According to the proposed method, the coordinates of the guiding
points on the wheel carrier are established by constructive criteria. Taking
into account the geometric constraints, for imposed positions of the wheel
carrier, the global coordinates of the joints on car body are determined. The
solution is obtained by the least square's approach.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Guiding Linkage, Rear Wheel, Geometric Synthesis.
by R. Mellah, R. Toumi
Abstract
- This paper presents an investigation on trajectory control of a PUMA560 robot
with six links derived by DC motors, using neural-fuzzy system with fast
learning algorithm, in order to make a fuzzy logic system more adaptive and more
effective. Such a compensatory fuzzy logic system is provide to be a universal
approximator. Because built by both control-oriented fuzzy neurons and
decision-oriented fuzzy neurons, if cannot only adaptively adjust fuzzy
membership functions but also dynamically optimize the adaptive fuzzy reasoning
by using a compensatory learning algorithm.
The structure of control system has two blocs. The first is used to identifier
the inverse dynamic model of the manipulator PUMA 560 by compensatory neural
fuzzy networks and the second bloc is used to find an appropriate input that
drives the manipulator to follow the desired trajectory, given by the sum of the
outputs neural-fuzzy network and feedback controller. Simulation results provide
adequate justification for current efforts to characterise unknown system using
the neural-fuzzy system approach.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Fuzzy logic; Online learning; Neural networks; Neural-fuzzy system; Adaptive
control.
Estimation of the Non-linear Limit Cycles of Autonomous Mechanical Systems Based
on a Constrained Non-linear Approach
by B. Hervé, J.-J. Sinou, H. Mahé, L. Jézéquel
Abstract
- In this paper, a non-linear method for determining limit cycles of non-linear
models of autonomous mechanical structures is proposed. Using approximations in
the form of truncated Fourier series, the resolution of differential equations
is changed into the minimization of specific functions. Not only the Fourier
coefficients are obtained but also the fundamental frequency of the non-linear
system is estimated. Moreover, this non-linear method allows the determination
of the stable and unstable limit cycles of non-linear systems subject to flutter
instability.
In order to show the efficiency of this non-linear approach, the method is
firstly applied on one- and two-degrees-of-freedom example models subject to
flutter instability. Then, the non-linear dynamic of the Lorentz’ chaotic system
is investigated. The obtained limit cycles are compared to time integration in
terms of accuracy and computing time.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Limit Cycles, Non-linear Method, Vibration.
An Efficient Algorithm for Computing n-Finger Force-Closure Grasps for Planar
Objects
by B. Bounab, D. Sidobre, A. Zaatri
Abstract
- This paper addresses the problem of computing n-finger equilibrium and
force-closure grasps of two-dimensional (2D) objects. Assuming hard-contact and
using Coulomb friction model, we develop new necessary and sufficient conditions
for n-finger to accomplish equilibrium and force-closure grasps. The proposed
conditions are based on the central axes of grasp wrench (i.e., force and torque
exerted by the fingers); we demonstrate that a 2D grasp is said to achieve
force-closure if and only if, the grasp wrench can generate any arbitrary
central axis. So, we present a simple and efficient algorithm for computing
n-finger force-closure grasps for planar objects. The proposed geometrical
force-closure test needs only some algebraic calculations, what facilitates its
real time implementation. We have implemented the proposed algorithm and its
efficiency is confirmed by examples.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Planar objects, force-closure, grasp wrench, central axis.
Deformations in Round-Profiled Threads and their Influence on the Screw
Durability
by I. Penkov, V. Strizhak, A. Sivitski
Abstract
- The article discusses a calculation procedure for determining deformations and
load distribution in round-profiled threads under general load conditions. It is
shown that on manufacturing of threaded parts with different classes of accuracy
owing to a small theoretical linear contact between screw and nut threads the
real contact can be moved up to rounded portions of the thread crests. In this
case the contact and bending deformations of the threads will have a great
influence on the screw durability. The equations for calculation both these
deformations and the deformations from thread shearing are given. The load
distribution in screw drive with the round-profiled thread is shown in
comparison with the load distribution in the widely used screw-drive with the
trapezoidal thread. The law of change of the load value on the most loaded
thread depending on a screw diameter and a number of the working threads are
given as well. A comparative analysis for guarantee the equal durability of the
thread and the screw shank is carried out.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Screw Drive, Round Thread, Deformations, Load Distribution.
Validation of Available Approaches for Numerical Bird Strike Modeling Tools
by M.-A. Lavoie, A. Gakwaya, M. Nejad Ensan, D. G. Zimcik
Abstract
- This paper investigates the bird strike phenomenon in order to validate
available numerical models through experimental tests and simulation tools. It
describes how to use the currently available test data while exerting caution as
to their reliability. The information is then used to evaluate the performance
of the different modeling options currently available. The evaluation is based
on five criteria that assess the quality of the bird models and the efficiency
of the numerical approaches. Therefore, a general guideline is established as to
how to set up the analysis of a bird strike and how to evaluate the obtained
numerical results.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Non-linear finite element analysis, impact simulation, bird modeling, ALE
method, SPH method, validation, bird strike test.
Static and Fatigue Characterization of Nomex Honeycomb Sandwich Panels
by B. Keskes, A. Abbadi, Z. Azari, N. Bouaouadja
Abstract
- The main benefits of using the sandwich concept in structural components are
the high stiffness, good fatigue resistance and low weight ratios. Recent
advances in materials and construction techniques have resulted in further
improvement and increased uniformity of the sandwich composite properties. In
order to use these materials in different applications, the knowledge of simply
their static properties alone is not sufficient but additional information on
their fatigue properties and durability are required.
In this paper, first static and fatigue tests on four points bending of nomex
honeycomb composite sandwich panels have been performed. Load/displacement and
S-N fatigue curves are presented and analysed. Fatigue failure and damage modes
are observed with an optical microscope and are discussed. The second is to
address such fatigue behaviour by using a damage model and check it by
experimentation. This fatigue damage model is based on stiffness degradation,
which is used as a damage indicator. Two non-linear cumulative damage models
derived from the chosen stiffness degradation equation are examined with
assumption of linear Miner’s damage summation. Predicted results are compared
with available experimental data.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Fatigue Model, Nomex Sandwich, Stiffness, Degradation, Failure modes.
Effect of Different Rolling Schedules on the Mechanical Properties and
Microstructure of C Mn (V-Nb-Ti) Pipeline Steel
by A. Guedri, D. Berdjane, S.Tlili, B. Merzoug, A. Zeghloul
Abstract
- High strength low-alloy (HSLA) steels have been used for the production of
welded pipes for more than 30 years. However, the alloy design of pipeline
grades is being continuously modified and the process technology optimized
because of increasing demand of high strength toughness combination requirement
of pipeline steels. The HSLA steels have demonstrated superior mechanical
properties through controlled rolling. In the present investigation, the effects
of processing parameters, such as finish rolling temperature, rolling reduction
and cooling rate, on the final microstructure and mechanical properties of a
grade X70 type HSLA steel has been studied by tensile and charpy impact tests
and optical microscopy. To yield better mechanical properties of X70
microalloyed steel grade, the optimization of the rolling process in the
laboratory experiment and rolling mill has been carried out.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Controlled rolling; Controlled cooling; Processing parameters; Micro alloying;
HSLA steel; Mechanical properties.
Continuum Based Solid–Shell Element Modeling for the Optimization of Composite
Multilayered Structures
by M. Hannachi, H. Naceur, J. L. Batoz
Abstract
- In this paper a general methodology for modeling and optimization of material
composite multilayered shell structures is proposed. It is based on the coupling
between solid-shell finite element modeling and response surface method. The
first part of the paper is devoted to the general FE formulation of the present
composite 8–node brick solid-shell element called SCH8γZ7, based only on
displacement degrees of freedom. A particular attention is given to alleviate
shear, trapezoidal and thickness locking. The anisotropic material behaviour of
layered shells is modeled using a linear elastic orthotropic material law for
each layer. In the second part of the paper, we focus on an adaptive response
surface method for the optimization problem. The response surfaces are built
using moving least squares approximations and design of experiments.
Applications to laminate thick shell structures are studied to validate the
methodology, and good results have been obtained in comparison with ABAQUS®
commercial code.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
3D–shell formulation, Composite structures, Optimization, Response Surface
Model.
Mechanical and Tribological Characterization of an Alloy of Surface Fe-Cr Formed
by Laser Remelting and the Effect of the Heat Treatment on the TTS
by H. Boudoukha, S. Djabi, B. Coquillet
Abstract
- Our study aims at the surface tribological transformation of an alloy of
surface Fe-Cr formed by laser remelting with power CO2 .We are
questioned on the behavior of this material under the effect of cyclic loading
with dynamic indentation with controlled load and without lubrication. The
microscopic analysis show us the behavior and the variations create after TTS
according to three considerations; the first is based on the mechanism of alloy
and its phenomenon of recrystallization, the second on the behaviour of this
alloy after quenching followed by a TTS and the third on the surface
tribological behaviour of same alloy after tempering.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Aluminum, Oxidation, Temperature.
Analysis
of the Thermal Behavior of a Ventilated Disc Brake
by M. Kaffel, H. Kchaou, M. Baccar
Abstract
- The major problem limiting the lifespan of a brake is the increasing of the
level of the temperature of the disc thus modifying its thermal and mechanical
characteristics. Concerning this effect, this study is devoted to the
development of a computer code necessary for the determination of the field of
temperature in all the volume of a disc brake. The three-dimensional
calculations carried out in transient mode on the aired disc brake, are founded
on the method of discretization to finite volume, and on the said technique, of
sliding boundary condition, which was developed to allow us to take into account
the variation of the relative position of the contact disc-pad, following the
rotation of the disc. The numerical results obtained, represent the fields of
temperature in various sections of the disc for the two types of braking, the
braking of stopping and the braking of maintaining, and put forward the
influence of the variation of the parameters of braking such as: initial speed,
deceleration, mass of the vehicle, and air of the surface of contact.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Disc Brake, Finite volume, Frictional Heat, Sliding Boundary Condition,
Temperature field.
Parametric Study
of the Salt Gradient Pond Stability
by F. H. Shehadi, A. Ben Moussa, M. Mseddi, M. Baccar
Abstract
- The problem of Mass and heat transfer and Stability within a salt gradient
pond (SGP) has been numerically investigated using a two-dimensional model. The
purpose of this study is to apprehend the hydrodynamic and thermal
characteristics of the SGP taking into account the Soret effect. The Navier-Stokes
equations under the Boussinesq approximation, energy and concentration equations
were discretized using the finite volume method. A parametric study of the fluid
hydrodynamic behaviour in the pond shows the influence of the thermal Rayleigh
and the Lewis numbers on the performance of the pond. We also carried out the
influence of the both Soret effect and the heat extraction on the stability of
the salt gradient pond. This work highlights the importance of the gradient
salinity to preserve the high temperature in the bottom of the pond.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Renewable energy, Salt gradient pond, Soret effect, Pond stability.
Air
Flow Patterns and Thermal Behavior in “King Tutankhamen Tomb"
by E. E. Khalil
Abstract
- The tombs of the Pharonic kings in "valley of the kings", Thebes, Egypt are
famous for their unique wall paintings and structure. KV62, King Tutankhamen
tomb, is the most famous because of the treasures it held intact for over three
thousand years. The burial chamber is decorated with scenes from the Opening of
the Mouth ritual, Book of the Dead, and representations of the king with various
deities. The current status of the tomb is very critical as pink stain and black
fungus spots have spread over decorated walls due to excessive moisture content
in the air. Visitors’ activities led to extra moisture production inside the
tomb, this would naturally lead to more pink spots and fungus activities. For
this purpose and in pursue of restoration operation it was suggested to design
and install a special ventilation system that would reduce the relative humidity
inside the tomb to normally acceptable environment for artifacts. Commercial CFD
codes are also used in order to simulate the indoor air conditions, air flow
velocities, temperatures and relative humidity patterns. A parametric
investigation to select the most suitable airside system design that doesn't
affect the archaeological theme of the tomb and that provides lower air
velocities around the wall paintings as well as lower air humidity all over the
tomb is reported.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
CFD, Air Conditioning, Simulation.
Innovative Use of Thermoelectricity for Nuclear Waste: Modeling, Estimation and
Optimization
by M. Lazard, H. Catalette, L. Lelait, H. Scherrer
Abstract
- The opportunity to generate thermoelectric power from a temperature gap in
nuclear waste is proposed and investigated. Models are developed in order to
estimate the parietal temperature and also temperature within the core of the
packages. Heat fluxes going through the thermoelements are then determined.
Formulation with thermal resistances is used to model the heat transfer. The aim
is to optimize the efficiency of such a device provided with thermoelements and
eventually with fins and to have a rough estimation of the energy available and
the electricity recovered.
Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
thermoelectricity, nuclear waste, heat transfer, modelling, thermal resistance.
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