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International Review of Mechanical Engineering - September 2007 - Papers

Effect of Microstructure on Crack Propagation of AISI304L Stainless Steel Pre-charged in Hydrogen, by A. Aboura, A. Seddak, J. D.Abascal
A Diffusive Model for Damping Waves in Viscoelastic Medium: Numerical Approximation, by B. Madi, H. Tebbikh
Numerical Modeling with the SFR Model of a Hyperelastic Behavior within Problems Involving Contact, by T. Ghomari, N. Talbi, R. Ayad, M. Ziane
Ellipsometric Characterization of Surface Quality for Polished Optical Glass Using Maxwell-Garnett Model in the Effective Medium Approximation, by A. Manallah, M. Bouafia, D. Bouzid
Prediction of Intralaminar Fracture Toughness of two Directional Glass Fibre Reinforced Polyester Laminated Composite Plate, by M. Rokbi, A. Imad, H. Osmani, N. Benseddiq
Experimental Study of the Influence of the Static Stiffness of Lathes on the Tool Wear Behavior, by F. Mahfoudi, L. Boulanouar
Study of the Effects of Sand Blasting on Soda Lime Glass Erosion, by T. Mahdaoui, N. Bouaouadja, M. A. Madjoubi, C. Bousbaa
Fuzzy Approach to the Vehicle Stability and Handling in Crosswind and Steering Manoeuvres, by B. L. Boada, M. J. L. Boada, A. Gauchía, J. A. Calvo, V. Díaz
Analysis and Deterministic Optimization of the Longitudinal Load Distribution Factors of Fine Pitch Gears of the I.S.O. Procedure, by F. Djeddou, R. Zegadi
Forward Kinematics of the 3S-6S Spherical Stewart Platform by Means of Screw Theory, by J. Gallardo, R. Rodríguez, C.-R. Aguilar, L. Pérez, L. Casique, M. Caudillo
On the Concepts of Action, Reaction, and Stress Wave Patterns in Structures, by L. T. Tenek
Modeling of the Cervical Vertebrae's Behavior to Wear, by M. Bendoukha, A. Hebbar, A. A. Belhachemi, A. Benkalfat
Control of Mobile Manipulator Using Resolved Acceleration with Iterative-Learning-Proportional-Integral Active Force Control, by E. Pitowarno, M. Mailah
An Analytic Solution of Some Rotating Electric Machines Vibration, by N. Herişanu, V. Marinca, B. Marinca
Kinematics and Dynamics of Mechanical Systems with Lubricated Revolute Joints: the Infinitely-Short Journal-Bearing Approach, by P. Flores
Failings Analysis of the Dynamic Boiler E.V.T MITTAL STEEL Complex Annaba Algeria, by D. Khalfa, A. Benretem, R. Chaib, Y. Benlali
CFD Analysis of Heat Transfer in Reciprocating Helical Coil with Piston Cooling Application, by P. W. Deshmukh, S. N. Sapali
Computation of Turbulent Forced Convection in Heat Exchangers Equipped with the Transverse Baffles, by R. Saim, S. Abboudi, B. Benyoucef, A. Azzi

International Review of Mechanical Engineering - Papers

Effect of Microstructure on Crack Propagation of AISI304L Stainless Steel Pre-charged in Hydrogen
by A. Aboura, A. Seddak, J. D.Abascal

Abstract - In the present work the effect of microstructure on Fatigue crack growth (FCG) behavior of AISI304L with different hydrogen content was investigated. The FCG tests were carried out at 10Hz, in air at room temperature, according to ASTM Standard. C (T) specimens with 2.5 mm thickness and 30 mm width were used for the tests. Specimens, with ASTM grain sizes of about 8, were charged with hydrogen by the electrolytic method at 50ºC before testing. The electrolytic solution used was 1N H₂SO₄ an acid solution with 0.25g/l of As₂O₃ oxide. Different current densities, varying between 50 and 300 mA/cm² were used. During the fatigue test, the length of the crack was measured with an extensometer and also optically, with a telescope and a video camera connected to a screen. The crack growth behavior as a function of the pre-charge parameters has been analyzed and various techniques (OM, DRX, SEM) have been applied in order to analyze the micro structural transformations produced and to relate them with the crack growth behavior.

Keywords: AISI304L stainless steel, fatigue crack growth, hydrogen embrittlement, microstructure.

A Diffusive Model for Damping Waves in Viscoelastic Medium: Numerical Approximation
by B. Madi, H. Tebbikh

Abstract - In this work, we develop an approach of fractional calculus applied to hyperbolic systems with fractional viscoelastic damping. We present a diffusive input-output model and a constructive method witch realizes this operation in a nonhereditary way. These tools lead to a simple formulation witch is easy to approximate numerically via standard methods.

Keywords: Fractional calculus, Diffusive representation, Viscoelastic system, numerical approximation.

Numerical Modeling with the SFR Model of a Hyperelastic Behavior within Problems Involving Contact

by T. Ghomari, N. Talbi, R. Ayad, M. Ziane

Abstract - An enhanced axi-symmetric finite element approach using a Mooney-Rivlin hyperelastic constitutive model is presented. Starting with a classical quadrilateral four-node element, a kinematical concept of fiber rotation in 3D space is introduced for improving the element’s accuracy. This concept, called SFR “Space Fiber Rotation” introduces adding rotational dofs without increasing the number of nodes. I order to take into account of the material incompressibility, during the plastic forming processes; a hyperelastic Mooney Rivlin model with a penalty technique due to Crisfield is used. Applications are essentially focused on axi-symmetric problems involving contact between solids. Results of the present SFR model perform well, with improving in all cases the computational time (CPU) especially when it’s compared to the expensive 8-node quadratic element.
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Keywords: Finite element, Hyperelastic, Mooney-Rivlin, Plastic forming process, SFR concept.

Ellipsometric Characterization of Surface Quality for Polished Optical Glass Using Maxwell-Garnett Model in the Effective Medium Approximation

by A. Manallah, M. Bouafia, D. Bouzid

Abstract - Ellipsometry is a technique of surfaces analysis, founded on the measure of light polarization state after reflection on a flat surface.
The present work consists in characterizing the surface quality of polished optical glass by ellipsometry and use of effective medium model. The measured ellipsometric parameters enabled us to obtain a correlation with surface roughness on the base of the theory of Maxwell-Garnett assuming an effective medium layer of effective thickness de and refractive index n_e.
Observations by Nomarski microscope made it possible to confirm the results obtained.

Keywords: Surface roughness, Optical testing, Polishing, Ellipsometry, Effective medium.

Prediction of Intralaminar Fracture Toughness of two Directional Glass Fibre Reinforced Polyester Laminated Composite Plate

by M. Rokbi, A. Imad, H. Osmani, N. Benseddiq

Abstract - The behaviour of notched laminate has not been addressed to any great extent in literature. Because of their anisotropic nature it is difficult to entirely envisage their mechanical characteristics and behaviour, particularly if they are produced with complicated architectures, as in the case of the woven reinforcements. This work is designed to provide more details on the effect of the orientation and site of the layers on the propagation of the crack in the laminates (2D). Seven laminate configurations were tested using the compact tension (CT) specimens according to ASTM Standard E399-90. The initialisation and the development of the zone of damage are studied by using digital image correlation (DIC) technique. Linear elastic fracture mechanics (LEFM) have provided good predictions for the failure loads of these composite and consistent values of fracture toughness for crack initiation, K_I-init., and crack propagation, K_I-prop., were calculated. These last can strongly be related to the lay-ups orientation.

Keywords: Translaminar fracture, Notched laminate, Fracture process, Lay-ups orientation.

Experimental Study of the Influence of the Static Stiffness of Lathes on the Tool Wear Behavior
by F. Mahfoudi, L. Boulanouar

Abstract - The aim of this paper is the study of the influence of the machine tools rigidity on the tool wear when turning with carbide tools in an industrial environment. The tests were carried on three different lathes characterized by their static stiffness. On each lathe, the evolution of the carbide tool wear was studied according to a method based of the experimental design included the cutting time, the cutting speed and the feed rate. Significant differences clearly appeared between the three machine tools showing the necessity of integrating of a rigidity parameter on the tool life models. Thus, a modified Gilbert tool life model included the rigidity of the machine tool was proposed which can be easily used for industrial applications.

Keywords: Machine-tool rigidity; Carbide tool wear; Tool life time model.

Study of the Effects of Sand Blasting on Soda Lime Glass Erosion

by T. Mahdaoui, N. Bouaouadja, M. A. Madjoubi, C. Bousbaa

Abstract - In Saharian regions, the erosion of glass by sand particles during sandstorms is a regular phenomenon. The progressive loss of matter on surface affects both the optical transmission and the mechanical strength. In the present work, we examine the effects of sand blasting on the erosion of soda lime glass intended for vehicles windshields manufacture. We used a sand coming from Algerian Sahara (Ouargla) which is characterized by a mostly rounded shape. All sand blasting erosion tests were simulated in laboratory. The erosive wear of soda lime glass is evaluated at different impingement angles (30, 45, 60 and 90°, with sand masses varying from 10 to 300 g and three different velocities (16, 20 and 24 m/s). The results obtained show that the erosion rate (E_r), the mean roughness (R_a) and the mass loss (∆m) reach their maximum at 90° (flow normal to the surface). After exposure to a sand mass of 300 g at normal incidence, the glass surface becomes totally blurred. The ∆m of the glass is 54 mg and the R_a reaches about 3.57µm and the optical transmission (T_o) is affected proportionally to the sand mass used (m_P). It decreases from 91.5% down to 12 % when the mass reaches 300 g. The morphologies of eroded surface were examined by the scanning electronic microscopy. From these observations, we noticed that the erosion mechanism is often of a brittle kind characterized by the formation of radial and lateral cracks that develop into chippings.

Keywords: Glass, Sand blasting, Erosion, Damage, impact, transmission, windshield.

Fuzzy Approach to the Vehicle Stability and Handling in Crosswind and Steering Manoeuvres

by B. L. Boada, M. J. L. Boada, A. Gauchía, J. A. Calvo, V. Díaz

Abstract - The wind disturbance greatly affects the vehicle’s behavior provoking that the vehicle does not follow the desired trajectory. This paper presents a new yaw moment control based on fuzzy logic to improve the vehicle handling and stability in crosswind. The advantages of fuzzy methods are their simplicity and their good performance to control non-linear systems. The developed controller generates the suitable yaw moment which is obtained from the difference of the brake forces between the front wheels so that the vehicle follows the target values of the yaw rate and the side slip angle. Simulation results show the effectiveness of the proposed control method when the vehicle is subjected to different cornering steering manoeuvres such as change lane and J-turn and a wind disturbance.

Keywords: Fuzzy Logic Control, Vehicle Dynamics, Vehicle Lateral Controller, Vehicle Model, Yaw Rate, Non-linear Control Systems.

Analysis and Deterministic Optimization of the Longitudinal Load Distribution Factors of Fine Pitch Gears of the I.S.O. Procedure
by F. Djeddou, R. Zegadi

Abstract - Estimation of the longitudinal load distribution factors is certainly the most complex, but unfortunately these factors have critical effect on the final rating of gears. The combined lead error of the teeth is usually the most critical accuracy factor in determining the load capacity of fine pitch gear pairs. Since, for similar gears of the same material (i.e, at the same stress level), the longitudinal load distribution factors are found to be higher for fine pitch gears than coarse gears. Many charts, equations and recommendations were stated by many standards and authors in order to estimate these factors. However most of these estimations were based on simple analysis and so many assumptions. For example ISO, method B and other standards such as BS 436 and DIN 3990 assume that the random component of the manufacturing error to be equal to the tolerance on the absolute value of the lead for the least accurate gear. To this must be added the effect of shaft, bearing and case elastic deflections to give the total lead error used to calculate face load distribution factors. In fact, the cumulative effect of combined tolerances on the lead can far exceed this assumption and may produce much greater random alignment variations.
In this paper; all possible sources of mesh misalignment are discussed, and an exact formulation is presented for a real single gear box for both overhung and straddle support configuration geometries. In addition, an optimization procedure has been applied to minimize these factors for both cases. The purpose of this paper is to present an alternative generalized approach to the minimization of the face load distribution factors of fine pitch gears after the design stage without altering the design parameters of the gears or their manufacturing process.

Keywords: Gear, Misalignment, Manufacturing error; Load distribution, optimization.

Forward Kinematics of the 3S-6S Spherical Stewart Platform by Means of Screw Theory
by J. Gallardo, R. Rodríguez, C.-R. Aguilar, L. Pérez, L. Casique, M. Caudillo

Abstract - In this work the forward kinematics of a decoupled Gough-Stewart platform is approached by means of the theory of screws. The forward position analysis is carried out using recursive procedures based on simple analytic quadratic equations, thus this initial analysis is free of unwanted solutions. Afterwards, the forward acceleration analysis is simplified considerably by taking advantage of the properties of reciprocal screws. The expressions thus obtained for the computation of the angular acceleration of the moving platform, and the translational acceleration of a point fixed to it, do not require the values of the passive joint acceleration rates of the manipulator. Of course, this contribution also provides, as an intermediate step, the forward and inverse velocity analyses of the mechanism. Finally, a numerical example is provided and the results obtained via screw theory are compared with results generated with special software like ADAMS©.

Keywords: Parallel manipulator, Decoupled motion, Klein form, Screw theory, Kinematics.

On the Concepts of Action, Reaction, and Stress Wave Patterns in Structures
by L. T. Tenek

Abstract - The paper discusses the classical concepts of action and reaction in mechanics. Based on these concepts we define the subsequent notions of elasticity and plasticity. While reaction due to stiffness and elasticity is associated with statics, fast load application and response may lead to concepts of vibration and dynamics with inertia and mass primarily responsible for the reactive response. Some physical examples are provided. Structural behavior due to reaction forces/moments can lead to a stress wave pattern (SWP), or waves in structures (wavy patterns). Computer simulations are provided. A discussion about mathematical modeling, redundant systems and various possible ways to equilibrate a load concludes the paper.

Keywords: Action, reaction, elasticity, plasticity, statics, vibration, stiffness, mass, inertia, reaction forces/moments, stress wave patterns.

Modeling of the Cervical Vertebrae's Behavior to Wear
by M. Bendoukha, A. Hebbar, A. A. Belhachemi, A. Benkalfat

Abstract - Cervicarthrosic pathology is a frequent reason for neurological and rhumatologic check up. Osteoarthritis at the cervical vertebrae level is the most widespread pathological entity which may appear relatively earlier in some cases at 20 years old, as well as for the older subjects. The therapeutic possibilities are multiple, varying according to the state of gravity of osteoarthritis, its evolutionary degree, its functional repercussion and the respective effectiveness of the various symptomatic treatments. Finally, the advanced degenerative attacks (serious hence invalidating for the patient) of the cervical column requires the use of the surgical means. The aim of this paper and by using the application of the experimental designs, we will try to highlight the organic mechanisms of the cervicarthrose. We carried out the tests by taking into account only the most dominating parameters which were the speed of the slide, the angle between vertebrae, and the applied charges. The calculation of regression allows us to obtain a mathematical model describing the wear of the disc by showing the interactions of the influential parameters.

Keywords: Osteoarthritis, Etiology, Intervertebral disc, Wear, Planning experiments.

Control of Mobile Manipulator Using Resolved Acceleration with Iterative-Learning-Proportional-Integral Active Force Control
by E. Pitowarno, M. Mailah

Abstract - A practical and novel method to control a mobile manipulator is proposed using a resolved acceleration with iterative-learning-proportional-integral active force control strategy. It is implemented as an approach for the robust motion control of a mobile manipulator comprising a differentially driven wheeled mobile platform with a two-link planar arm mounted on top of the platform. The resolved acceleration control is used to manipulate the kinematics of the system in the outermost control loop configuration while the active force control located within the loop is employed to compensate for the dynamic effects including disturbances and uncertainties. The effectiveness and robustness of the proposed scheme is investigated considering a number of introduced disturbances in the forms of impact and vibration forces while the mobile manipulator is performing a trajectory tracking task. The scheme is also validated through an experimental study using a fully developed mobile manipulator prototype. Both theoretical and experimental results verify the viability of the proposed scheme in producing the desired robust motion control performances.

Keywords: Mobile Manipulator, Robust, Resolved Acceleration, Iterative Learning, Active Force Control.

An Analytic Solution of Some Rotating Electric Machines Vibration
by N. Herişanu, V. Marinca, B. Marinca

Abstract - In this paper dynamic behavior of a rotating electric machine subjected to parametric excitation caused by an axial thrust and a forcing excitation caused by an unbalanced force of the rotor is analytically investigated. In order to obtain analytical solution, the Extended Homotopy Analysis Method (EHAM) is employed, which have a distinct advantage in that this procedure is valid even if the considered equation does not contain any small or large parameter. In order to validate the obtained analytical results, numerical simulations were performed and a very good agreement was found.

Keywords: Rotating electric machines, Extended Homotopy Analysis Method.

Kinematics and Dynamics of Mechanical Systems with Lubricated Revolute Joints: the Infinitely-Short Journal-Bearing Approach
by P. Flores

Abstract - This paper deals with a methodology to assess the influence of the lubricated revolute joints in the kinematics and dynamics of mechanical systems. The existence of the clearance at revolute joints is inevitable in all mechanical systems and most of them are designed to operate with a lubricant fluid. In the present work, the infinitely-short journal-bearing approach for dynamic loads is used to evaluate the resulting hydrodynamic forces of the pressure distribution in the lubricated revolute joints. These hydrodynamic forces are then introduced into the system’s equations of motion as external applied forces. A numerical example is presented in order to demonstrate the efficiency and accuracy of the methodology and procedures adopted in this work. The numerical results point out that the existence of lubricated joint can affect the kinematics and dynamics of system.

Keywords: Infinitely-Short Journal-Bearing, Lubricated Revolute Joints, Mechanical Systems.

Failings Analysis of the Dynamic Boiler E.V.T MITTAL STEEL Complex Annaba Algeria
by D. Khalfa, A. Benretem, R. Chaib, Y. Benlali

Abstract - The majority incidents in the natural circulation steam generators is associated with the variation of the thermohydraulics parameters as well as the abrupt explosion of the vaporiser tubes and superheater. The object of this study is aimed to the assessment of the principal cause of explosion of the vaporizer tubes in the dynamic boiler E.V.T –MITTAL STEEL complex -Annaba- Algeria- The finalized trial program concerns the evaluation of the two phase flow heat transfer coefficient and the internal temperature wall by a Kandlikar model,.the application of this last show that we have a bad flow quality in vaporizer tubes provokes the increase of the heat transfer coefficient and cause the explosion, how it in accord with our results.

Keywords: explosion, vaporizer tube, critical overheating, nucleate boiling, vaporization.

CFD Analysis of Heat Transfer in Reciprocating Helical Coil with Piston Cooling Application
by P. W. Deshmukh, S. N. Sapali

Abstract - This study focuses on the Computational Fluid Dynamics (CFD) analysis that could lead to a physically consistent correlation, which assist to evaluate the local heat transfer in the reciprocating helical coils by permitting the individual and interactive effects of centrifugal force, torsional force, pulsating force and reciprocating buoyancy on the forced convection to be quantified. A rapid and robust Navier-Stokes flow solver in finite volume formulation (Fluent) has been used for simulation of flow and conjugate heat transfer. Steady state and transient heat transfer analysis with several operating conditions is carried out for static and reciprocating coil conditions. A grid independent analysis is also presented. Comparison with the experimental data indicates that the simulation methodology is accurate enough.

Keywords: Reciprocating Heat Transfer, Spiral Cooling Passage.

Computation of Turbulent Forced Convection in Heat Exchangers Equipped with the Transverse Baffles
by R. Saim, S. Abboudi, B. Benyoucef, A. Azzi

Abstract - In this paper, structure of the turbulent flow and heat transfer in tow-dimensional horizontal channel are investigated and analyzed numerically. The air circulates inside a channel of rectangular section, containing two rectangular baffle plates. Tube with baffle inserts can serve as an effective application for augmenting forced convection heat transfer. This is an important problem in the scope of heat exchangers where the characterization of the flow, pressure distribution, as well as the existence and the extension of possible recirculation need to be identified. The turbulent governing equations that describe the flow are solved by a control volumes based on the finite Volume Method, employing the TEAM code (Turbulent Elliptic Algorithm Manchester) with the k-ε turbulence model. The velocity and pressure terms of momentum equations are solved by SIMPLE (semi-implicit Method for pressure-linked equation) method. The mean velocity profiles, the velocity and temperature fields as well as the Nusselt number distribution are presented for a typical case and for the representative value of Reynolds Number.
The numerical calculations of the flow field indicate that the flow patterns and the recirculating zone changes its orientation as the blockage ratio (e/H) and the Reynolds number (Re) increase.
Concerning the heat transfer effects, the results shows that the Nusselt number on the channel walls are strongly increased by increasing the baffle height and the Reynolds number. Comparisons between numerical and experimental results in literature in the velocity fields show reasonable agreement.

Keywords: Finite volume method, Turbulent flow, forced convection, baffle.

International Review of Mechanical Engineering - September 2007 - Papers

Numerical Modeling with the SFR Model of a Hyperelastic Behavior within Problems Involving Contact

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