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International Review of
Mechanical Engineering - Papers
Abductive Approach using Fuzzy Petri Nets for Industrial System Diagnosis
by A. Ghernaout, A. Liazid, A. Benamar, N. Zerhouni
Abstract
- In an industrial decentralization context of control and migration of
intelligence downwards, mechanical equipments with more and more electronics and
automations have been developed given the so called mechatronic systems. However
this rapid progression of new technology has contributed to increase the systems
complexity and decrease the mastering. The industrial diagnosis associated at a
precocious detection of degradations have a key role in quality mastering,
availability improve and productivity of the production tool.
The industrial diagnosis methods are divided in two categories: diagnosis
methods with formal model of the equipment and diagnosis methods without
equipment model. The formal mathematical models of industrial equipments are
often with uncertainties and difficult to built.
This paper proposes a method based explanatory model which is best suited to
model the cause-effect relationships essential for the industrial diagnosis. We
adapt a novel tool of assistance to diagnosis based on the fuzzy Petri nets (FPN).
An industrial application concludes this work.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Industrial diagnosis, artificial intelligence, fuzzy Petri nets, explanatory
model, fault tree, FMEA.
Effects of Tool Modularity and Learning of Manufacturing on the Machining Costs
of a Molding Tool
by M. T. Kainusalmi, R. S. Kinisjärvi, J. P. Varis
Abstract
- Businesses have an increasing need to introduce new products onto the market
at a more and more rapid cycle. Consequently, modularity has become quite a
common feature in a number of product lines. Modularity enables the production
of a wide range of products with a relatively small number of modules that are
independent of each other. With an extensive product range, a company can better
respond to the needs of a diverse customer base. A company can gain an edge by
preparing a competitive strategy which helps it stand out from its competitors.
Modularity provides excellent possibilities for applying any strategy, be it
built on cost leadership or unique products as the source of competitive edge.
In this case study, an integrated sheet metal molding tool was redesigned mainly
because its structure limits end product variation and its purchase price is
high. The aim of the study was to develop a very simple molding tool with low
manufacturing costs which, with only minor changes, can manufacture a variety of
end products. As an outcome, a modular molding tool with a completely new
structure was developed. It allows the manufacture of different end products
merely by changing a few shape-giving parts. In addition to end product
flexibility, modularity results in significantly lower costs than integrated
solutions. The asking price of an integrated molding tool for a new product
amounts to approximately € 12 000, whereas, according to a learning curve based
manufacturing cost analysis, those of a modular tool add up to less than half of
that, approximately € 5 800.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Molding tool, modular, learning curve, costs.
by S. Kumar, A. Haleem
Abstract
- This paper deals with an extensive literature review on bullwhip effect in the
current scenario. Bullwhip effect has become an important area of research in
supply chain management. A literature review to understand process of bullwhip
effect, its sources and measures along with risk associated with, have been
undertaken. Procedures for reducing bullwhip effect have been also discussed in
a supply chain configuration for collaboration. Bullwhip effect will be an
important parameter towards the success of retail houses. In order to deal with
the issue different sources of bullwhip effect are being identified. These
sources are demand signal processing, rationing game, order batching and price
fluctuation. Technique for benchmarking this effect is also being explored.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Bullwhip effect, Supply Chain Management, Demand signal Processing, Rationing
game, Order Batching.
Impact of Wheel Ageing on Rail Corrugation in Curve: A Parametric Study
by C. Collette, R. Bastaits
Abstract
- This paper investigates the impact of the wheel profile aging on the
development of rail corrugation. The test case considered for the study is a
curved track section from the Brussels metro network (STIB). Rail corrugation is
evaluated using a multi-body model of the vehicle and the track. The effect of
wheel diameter and shape of the profile are evaluated for the test case
considered using the multi-body model.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Railway wheel profile, Multi-body model, Stability, Rail corrugation.
Automatic Determination of Operations Number for the Conventional Machining of a
Surface
by A. Noureddine, A. Benamar
Abstract
- According to the machining quality and the desired state of surface, the
realization of a surface by machining will need one, two or three operations,
called direct finishing, rough machining/finishing, rough machining/semi
finishing/finishing.
The determination of the number of operations to apply in order to obtain a
surface in conformity with the required specifications by the technical drawing
obeys to a specified number of rules wich we will make explicit in order to
deduce a method. This method can be modeled into an algorithm to develop an
application allowing the calculation of the number of operations.
We are interested by the parts that are following Iso-quality dimensioning rules
on conventional machines. This work seems useful in Algeria because machining of
mechanical parts is very important with conventional machine-tools.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Machining quality, roughness, machined surface, tolerance interval, machining
elementary operation, passes number.
Effect of Diamond Ball Burnishing on Surface Characteristics and Fatigue
Strength of XC55 Steel
by H. Hamadache, A. Amirat, K. Chaoui
Abstract
- Investigation on the effect of surface quality of lathe machined down XC55
steel work piece on the fatigue strength has been carried out. The mechanical
surface treatment was achieved by elastic-plastic cold working in the
near-surface region through a ball burnishing finishing operation. The results
showed improvement in surface roughness (Ra) from 1.49 µm to 0.45 µm and
increase in hardness (Hv) from 300.8 to 537.35. These were in good agreement
with results predicted from a mathematical model based on full factorial
experiment method.
The fatigue strength of pieces subjected to ball burnishing revealed 40% and 30%
high resistance then those pieces that have respectively undergone lathe turning
and grinding. This was due to compressive residual stresses that the burnishing
process generated on the outer surfaces.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Machining; Ball burnishing; Roughness; Hardness; Residual stresses; Fatigue
strength.
Data Mining Techniques and Singular Spectrum Analysis for Tool Condition
Monitoring in Metal Cutting
by B. Kilundu, P. Dehombreux
Abstract
- This paper explores the use of data mining techniques for tool condition
monitoring in metal cutting. Pseudo-local Singular Spectrum Analysis (SSA) is
performed on vibration signals measured on the toolholder. This is coupled to a
pass-band filter to allow definition and extraction of features which are very
sensitive to tool wear. These features are defined, in some frequency bands,
from sums of Fourier coefficients of reconstructed and residual signals obtained
by SSA. Rates of recognition of wear are very good and exceed 80 %. This study
highlights two important aspects: strong relevance of information in high
frequency vibration components and benefits of the combination of SSA and
pass-band filtering to get rid of useless components (noise).
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Data mining, vibration signal, singular spectrum analysis, tool condition
monitoring.
Damage Mechanism of a Sandwich Material Tested Under Static and Cyclic Loadings
in a Three Points Bending Experiment
by S. Ellagoune, L. Fatmi, A. Rouili
Abstract
- This paper presents the results of an experimental investigation on the damage
mechanism of a sandwich material, tested under static and cyclic loading
conditions in a three points bending test. Four loading levels were considered
for different number of loading cycles and rates of loading. The samples were
tested using a Universal machine (Zwick Roelle) allowing a loading capacity of 5
kN, monitored by a computer. The main results obtained show that for the three
loading rates investigated, increasing the cyclic loading level causes a
decrease in the deformation energy of the sandwich material. This observation
was confirmed by the evolution of the damage mechanism related to the number of
cycles applied to the sample. When analyzed by means of the optical microscope,
the damage and failure mechanisms were found to be linked to the delaminating of
the Core-thickness and failure of the fibers.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Sandwich material, cyclic loading, 3 points bending test, damage mechanism.
Influence of Internal Gears Rim Thickness and Design on Gearmesh Stiffness
by M. R. Letaief, F. Chaari, M. Haddar
Abstract
- In this paper, a finite elements model of a gear system composed of external
and internal gear is developed. The gearmesh stiffness which is the main
excitation source of the system is computed for various cases of the internal
gear design. The rim thickness, the shape and the fixing mode are varied. It is
shown that this design affects considerably the evolution of the gearmesh
stiffness which will certainly affect the dynamic behaviour of the internal gear
system.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Gearmesh stiffness, Internal gear, Rim shape, Rim fixing.
Morpholological Investigations in the Wear of Carbide Inserts in Milling
by M. Benghersallah, L. Boulanouar, A. Devillez, S. Dominiak, D. Dudzinski
Abstract
- This study is based on the examination of the morphology of the wear of the
P35 metal carbide inserts and the carbide inserts with simple coating lay down
TiN. The analysis was carried out initially by an exploration of the plates by
white light interferometric microscope to white light. A second examination of
the plates is carried out by the scanning electronic microscope with sweeping.
The interferometric examination enabled us to evaluate with a very high degree
of accuracy the depth of wear in the substrate composing materials of cut. It
also allowed us to evaluate the thickness of the layer of the coating. The
examination on the SEM consists in investigating wear and studying its
morphology and identifying the chemical composition of the substrate used for
the manufacture of the plates. The obtained results will be used to describe the
nature of wear and the mechanism of its formation.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Carbide inserts, Coatings chock, Wear, White light Interferometry, Milling.
The Relationship between Auxetic and Negative Stiffness Materials Behavior. Part
I. Theory
by V. Chiroiu, L. Munteanu, D. Dumitriu
Abstract
- The purpose of the paper is to study the relationship between the behavior of
auxetic and negative stiffness materials. These materials are modeled as chiral
Cosserat media. The classical mechanics fails when describes the behavior of
auxetic and negative stiffness materials, because these materials exhibit chiral
effects and non-affine deformations. A new architecture for a cellular elastic
solid with a chess board structure composed from auxetic materials of positive
and negative stiffness, is proposed. The characterization of the cellular solid
with the calculation of material constants will be presented in the forthcoming
paper.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Auxetic material, Negative Poisson’ratio, Negative stiffness material, Chess
board structure.
Transport and Contact between Rigid Bodies to Simulate the Jam Formation in
Urban Flows
by S. Hadji, H. Naceur
Abstract
- This study deals with simulation of interaction of bodies in urban flow when
the bodies are assimilate to have a rectangular shape. A Galerkin type finite
element discretization with velocity field richer than pressure field is
employed to obtain the fluid discretized non-linear relations. The particles
displacements are computed by using a rigid-body motion method and a collision
strategy is developed to handle cases in which bodies touch.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
2D horizontal flow, Saint-Venant; Finite element, Particles, Interaction,
Collision.
On the Characteristic Paths of Unsteady Incompressible Flows with Artificial
Compressibility
by K. Zamzamian, S. E. Razavi
Abstract
- In this paper the characteristics of unsteady two-dimensional incompressible
flows are obtained along with artificial compressibility. At first, the
characteristic relations for one-dimensional flow are derived in a routinely
manner. Then, they are extended for the two-dimensional case based on a novel
approach. Mach cone and conoid passing from a point in an incompressible flow,
paths of information propagation and corresponding Riemann variables are
extracted using consistency and compatibility relations. It was found that the
directions of pseudo acoustic waves within the incompressible flow are functions
of artificial compressibility parameter which also shows the subsonic nature of
flow. Unlike the compressible flow equations, the cross-section of Mach conoid
with x-y plane is an ellipse having major and minor diameters parallel to
coordinate axis. The domain of dependence of a point is formed by waves which
propagate tangent to the Mach cone. Information propagation directions and
velocities are all functions of artificial compressibility parameter.
Finally, this paper leads to following concepts:
a) Physical interpretation of pseudo-wave propagation in two-dimensional
unsteady incompressible flow.
b) The influence of artificial compressibility parameter on characteristic paths
of incompressible flows equations.
c) Feasibility of numerical flux design based on genuinely two-dimensional
characteristics of incompressible flow equations without any simplifying
assumption such as using one-dimensional characteristics relations for
two-dimensional flows.
Overally, the newly obtained characteristic equations can be used as information
propagation patterns for multi-dimensional incompressible flows.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Incompressible flow, Artificial compressibility, Two-dimensional
characteristics, Mach conoid, Riemann variables, Wave angle.
Accurate Temperature
Control Using Heat Pipes
by T. Kaya, D. Mishkinis
Abstract
- The precise temperature control of heat generating instruments under varying
heat loads and sink conditions is a highly challenging task in designing thermal
control systems. For space missions with very narrow temperature range
requirements, this task is further complicated. In this paper, accurate
temperature control methods using two-phase heat exchange devices, heat pipes
and loop heat pipes, are investigated. The temperature control methods with a
flight heritage and at the development phase are both reviewed. Design
guidelines are recommended to help selecting the optimum thermal control method.
Due to the limited power available in space missions, the control heater power
is considered as the main driving requirement. The other parameters taken into
account include: passive operation, reliability, mass, complexity, and
temperature stability.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Heat Pipes, Loop Heat Pipes, Temperature Control, Two-phase Heat Transfer.
Assessment
of Jet-wake Flow Structures Induced by Three-dimensional Hub Wall Contouring
by N. Rochuon, I. Trébinjac, P. Kulisa, G. Billonnet
Abstract
- An analysis of particular flow features induced by three-dimensional wall
modification of a high-pressure centrifugal compressor impeller is presented.
Referring to a first axisymmetric hub geometry previously studied, a second
impeller was designed in order to reduce the effects of the jet-wake flow
structure that develops in the curved part of the impeller and propagates
downstream, up to the diffuser inlet. In this configuration, the hub radius
rises from main-blade pressure side to next main-blade suction side.
The analysis of the flow fields is based on results of steady three-dimensional
simulations. An entropy augmentation very close to the shroud produced a
decrease in impeller performances while the diffuser performances remain the
same. The analysis of the three-dimensional flow field shows a reduction in
vortical structures from the high meridional curvature region up the impeller
exit, leading to a cutback of the jet-wake structure.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Centrifugal compressor, Wall contouring, Numerical simulation, Turbomachinery.
A
Beam FiniteElement Based on the Explicit Finite Element Method
by L. T. Tenek
Abstract
- The present article presents a new three-dimensional beam finite element, the
element EB6, based on explicit theory [4]-[6]. To the element is assigned a set
of modes. A diagonal Modal elemental stiffness matrix is formed which through a
series of matrix transformations relates to the local and global coordinate
systems. An initial load due to temperature is derived, as well as the elemental
mass matrix and the geometric stiffness. All quantities are explicitly defined.
The element is used to study a number of beam, arc, and frame structures.
Computational aspects of the element are also provided.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Explicit FEM, beam element, modes, stress wave pattern, computing.
An
Explicit Quadrilateral Shell Element
by L. T. Tenek
Abstract
- The present study introduces a 4-node quadrilateral shell element (which is
called EQ7) for the analysis of plates and shells. The element is a flat element
with 6 degrees of freedom at each node; three displacements and three rotations.
It is based on the Explicit Finite Element Method. All quantities, matrices,
etc., are explicitly derived. We apply to the shell element a number of modes
and besides the Modal Stiffness Matrix we introduce the Modal Mass Matrix and
the Modal Geometric Matrix. We employ also an iterative scheme for the solution
of the linear system of equations. Numerical simulations are provided. Stress
Wave Patterns are found in deforming plates and shells. Because all quantities
are explicitly derived, the theory and method is suited for efficient computer
implementation.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Shell element, modes, modal matrices, stress wave patterns.
Optimization
of Vibration Frequencies of Rotors via Rayleigh-Ritz Method and Genetic
Algorithms
by J. L. Marcelin
Abstract
- This paper deals with the optimization of vibration frequencies of rotors
using Rayleigh-Ritz function approximations in computationally intensive genetic
design, in the dynamic field. The research strategy consists in substituting an
approximate response from a Rayleigh-Ritz method for finite element calculations
in the optimization process (genetic algorithm). It is demonstrated that using
GAs with the Rayleigh-Ritz method is a very attractive and powerful response for
such a problem, that is when the objective function has no derivatives and when
several optimal solutions simultaneously exist.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Optimization of rotors, Rayleigh-Ritz, Genetic Algorithm.
Application
of Virtual Reality in Improvement and Optimization of Bump Steering Response of
McPherson Suspension Mechanism
by H. Habibi, K. H. Shirazi
Abstract
- In the present work the bump-steering characteristics of front suspension
system is optimized using the kinematic modelling in the three-dimensional
virtual space. The virtual space is prepared by the engineering software namely
Visual Nastran (VN). The bump-steering is defined as uncontrollable changes in
the steering angle of steered wheels due to the bumping. This uncontrollable
rotational motion of the wheels not only affects the dynamic stability of the
vehicle but also it can be a source of tire wearing and shimmy. Although due to
the three-dimensional nature of the suspension mechanism it cannot be completely
suppressed. In this paper, the special career to simulate of the
three-dimensional linkage of McPherson-strut mechanism for bumping maneuver in
software medium is briefly explained. Then a 3D kinematic analysis utilizing
vectorial mathematics is developed so after determination of kinematic behavior
of mechanism in bumping situation it would be able to check the reliability of
built suspension mechanism in VN space for performing the optimization process.
Using the prepared model a study for minimizing the steering errors including
deviation of camber, caster and steering angles due to the bumping of the front
wheel versus the dimensional properties of the mechanism is accomplished. To
achieve the best steering performances, the optimum length and angle of the
mechanism’s members are obtained. It is shown that for synthesis, design,
improvement and optimization of such three-dimensional linkages, the virtual
reality can be applied as a fast and reliable tool.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Bump steering, McPherson-strut, Optimization, Steering angle, Visual Nastran.
Numerical
Simulation of Solidification Processes in Continuous Casting. Influence of
Casting Speed
by M. Belahouel, R. Boumedmed
Abstract
- In the continuous casting process, the mould region is a key tool to improve
steel cleanliness; however its major role is the setting of cast product form
and to ensure a formation of a sufficiently thick solidified shell to contain
the molten metal at the exit of mold. In recent years, many mathematical models
for continuous casting have been developed Most of the models, presented in
literature can only be used for simulation of steady state casting using a
finite element or finite difference methods. In this paper, two dimensional
numerical prediction of slab solidification in the continuous casting is
presented. Numerical prediction is based on the commercial finite volume
software FLUENT (6.2). On the basis of numerical results, it is possible to
calculate temperature field distribution in mould region, temperature profiles
and the thickness of solidified shell. Thereafter, to predict the impact of
casting speed on slab continuous casting.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Continuous casting; Numerical model; Heat transfer and solidification; Casting
speed.
Biomimetic
Actuation and Control of an Anthropomorphic Finger
by Konstantinos Andrianesis, Anthony Tzes, Efthymios Kolyvas, Yannis Koveos
Abstract
- One of the primary issues in the development of compact and lightweight
anthropomorphic devices is closed related to the utilized actuators and their
capability to operate in a muscle-like, biomimetic way. Novel, smart material
based, high powered actuators such as Shape Memory Alloys (SMAs) prove to be
competent to serve this purpose. In this article, a lightweight anthropomorphic
finger actuated by SMAs is presented. The finger prototype is patterned after
human anatomy and consists of three pin joints allowing flexion-extension
movements. Flexion movements in each active joint are achieved via the
contraction of thin integral SMA wires, while antagonistic force for extension
movements is provided by standard coil springs. Open and closed loop control
tests are conducted using direct visual sensory information as feedback and
classical decoupled PID/PD controllers providing satisfactory system responses.
The experimental results show in practice the alloys’ potential encouraging
future works with this type of technology.
Copyright © 2008 Praise Worthy Prize S.r.l. - All rights reserved
Keywords:
Anthropomorphic Finger, Image Processing, NiTi actuators, Shape Memory Alloys.
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