# Larbi El BakkaliAbdelmalek Essaâdi University | UAE · Department of Physics

Larbi El Bakkali

Professeur de l'Enseignement Supérieur à l'UAE

## About

78

Publications

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478

Citations

Introduction

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October 1982 - present

## Publications

Publications (78)

The robot manipulator is a mechanical system multi-articulated, in which each articulation is driven individually by an electric actuator is the most robot used in industry, this system need an efficient control strategy. In this present work we present a new approach for a robot manipulator with two degrees of freedom based on the Fuzzy Logic Cont...

The effects of the heterogeneity of liquid on the tank sloshing under pitching excitation are analyzed and discussed. The time history of the free surface elevation for tank containing a homogeneous-heterogeneous liquid are recorded and discussed. Numerical simulations are performed for various functions of density using the finite-element method....

The main goal of the present paper is to approach the modeling of one of the most important and critical failure modes for composite laminates which is known as interlaminar delamination in the aeronautical structures. The analytical model is based on a fracture mechanics approach; it’s used to estimate the total mixed mode energy release rate for...

This paper provides workspace determination and analysis based on the graphical technique of both spatial and planar parallel manipulators. The computation and analysis of workspaces will be carried out using the parameterization and three-dimensional representation of the workspace. This technique is implemented in CAD (Computer Aided Design) Soft...

Dans ce travail nous allons traiter la synthèse optimale du mécanisme à quatre barres pour le cas de génération de trajectoire. La technique de recherche utilisée est basée sur une approche d'optimisation fondée sur un algorithme métaheuristique, exploitant les notes de musique associées à une fonction objectif, cette fonction qualifie l'habilité d...

In this paper, the comparison analysis has been presented based on performance indices since it is considered as the essential criteria for robot evaluation. Two spherical serial kinematic structures are proposed for the comparative study, which comprises a three rotational joints having concurrent axes, the first one has an orthogonal axis and
the...

The trajectory planning problem of robot is addressed in this paper, which is consist of finding an optimal trajectory for a given path from an initial and final positions in the operating space. We aim to determine the optimal trajectory for three degrees of freedom spherical wrist with concurrent axis by using genetic algorithm. The optimized tra...

This paper highlights workspace modeling of two parallel robots based on CAD technique. The algorithm is presented and described for the generation of each workspace, which is implemented in CATIA software. The impact of different design parameters on the reachable workspace of DELTA robot manipulator is discussed. Finally, an optimization example...

The objective of kinematic synthesis is to determine the mechanism dimensions such as link lengths, positions or joint coordinates, in order to approximate its output parameters such as link positions, trajectory points, and displacement angles. Kinematic synthesis is classified into three categories: function generation, path generation, and motio...

This work presents a simple and yet powerful approach for quantitative and qualitative evaluation of the performance of 3-UPU spatial parallel robot. The quaternion approach is used to obtain graphically the workspace of the 3-UPU parallel manipulator. The Jacobian matrix is developed then used to search for conditions that lead to singular configu...

Parallel robots display important advantages over their serial mechanisms in several applications where both accuracy and dynamic response are needed. Parallel manipulators have been developed extensively for applications that need high accuracy, speed and stiffness, which make them, useful in important fields. But during the designing of the paral...

Optimal path planning for robot manipulator plays an important role in the domain of robotics. In this work, we use Ant colony algorithm as an optimization tool because ACO has been known to be robust for search and optimization problems. The Ant colony algorithm has been used to find the optimal path from an initial to a final position in the pres...

The authors study the small oscillations of a system of two nonmixing fluids, the lower inviscid, the upper viscoelastic, in an open container, restricting themselves for the second to the more simple Oldroyd model. From the equations of motion, they obtain a variational formulation of the problem, from which they deduce a variational equation for...

Wind turbine became an important source of energy, more advanced in these technology and structures, the complex system modelling with a high degree and flexible bodies by classical methods is a difficult task, the aim of this labour is to apply a graphical method that based on the principle of energy's conservation to develop a mathematical model...

Robots are increasingly resorted to in medical application due to their high accuracy and precision. Among many types of medical applications, tele-echography system is widely used for its convenience and safety. This paper describes a new architecture of a medical manipulator system for tele-echography application. The kinematic structure of the p...

The main purpose of this work is to characterize and discriminate the respective roles of the thermo-mechanical gradient in the damage mechanisms of composite laminates used in aeronautics in order to understand the initiation and evolution of damage modes. For this purpose, a finite element model of compact tension specimen with a series of virtua...

Conference on Civil Engineering and Materials

In this paper, dynamic analysis of a parallel robot is presented using the most popular approach named the Newton-Euler formulation. In this method, the dynamic formulation for each limb and the moving platform must be derived which leads to the calculation of all forces, and this can be helpful in the design of parallel manipulator. In this way, d...

In this paper, a novel six degrees of freedom that are five degrees of rotational freedom and one degree of translational freedom, hybrid robot is proposed. The robot is used in tele-echography application. It main task is to hold and place a probe on the patient's skin during an examination. The robot structure consists of two modules: The first o...

The problem of the small oscillations of an ideal liquid contained in a
vessel in uniform rotation has been studied by Kopachevskii and Krein in the
case of an entirely rigid vessel [3]. We propose here, a generalization of
this model by considering the case of a vessel closed by an elastic circular
plate. In this context, the linearized equations...

Buckling of imperfect thin shell tank which is subjected to uniform axial compression is analyzed. The effect of internal pressure on the stability of a shell tank filled with a homogeneous-heterogeneous liquid was considered. Investigation of the liquid nature effect on reduction of the shell buckling load is performed by using the finite elements...

By taking 3RRR planar parallel robot the object of this study, this work presents an optimal trajectory planning of 3RRR parallel robot. Indeed, Parallel robot is fundamentally a closed-loop kinematic chain mechanism in which the end-effector is connected to the base by several independent kinematic chains. Due to the potential advantages of parall...

In this paper, we present a modeling study that combines some mathematical models in order to discover the effect of the environment pressure studied on the force on the wind rotor. Indeed, there are other parameters affecting the aerodynamic force which the wind speed, temperature and the radius of the blade. This study allows us to analyze and ev...

To estimate production and to evaluate the performance of the energy conversion system of a wind turbine. In this paper we propose a new study for modeling and simuling the performance of a type of wind turbine (Bornay3000) implemented in the hybrid system on the site of Laboratory for Applied Research in Renewable Energy (LRAER). Our system's simu...

In this paper we propose a new study for modeling and simulation the performance of (Bornay3000) wind turbine implemented in the hybrid system on the site of Laboratory of Research Applied to Renewable Energy (LRAER). It gives also, estimation and evaluation of the production which encompasses performance of the energy conversion system of a wind t...

Spatial mechanisms have been an intensive area of research for over a decade, for their advantages such as good stiffness, large load capacity, and high accuracy, in comparison with the traditional serial mechanisms. The arm manipulators require an actuator for each axis, and a large number of degrees of freedom DOF, which make them expensive. In t...

Wind energy is affected by the stochastic nature of the wind speed, the purpose of this labor is to improve the machine's production efficacy. This control strategy estimates the restoring torque of generator adjusting the generator speed ratio, in this paper we will apply a fuzzy logic strategy to maximize the power by optimizing parameter adjusti...

The problem of manipulator control is a highly complex problem of controlling a system wich is multi-input multi-output, non linear and time variant. In this paper we present a new approach for a robot manipulator with two degrees of freedom based on the intelligent adaptive fuzzy PID, Parameters which guide the functioning of Proportional Integral...

In this work we present an optimal design for a type of serial link manipulators based on multi objective optimization. The objective functions considered are Global Conditioning index (GCI) and workspace volume, the first indice is based on condition number of robot manipulator Jacobian matrix and the objective functions are optimized simultaneous...

The robot manipulator is a mechanical system multi-articulated, in which each articulation is driven individually by an electric actuator, it is the most robot used in industry, this system need an efficient control strategy, such as Fuzzy Logic law control, by means each articulation is controlled independently, this kind of control present a lot...

Soil erosion is a complex phenomenon which yields at its final stage insidious fluid leakages under the hydraulic infrastructures known as piping and which provokes their rupture. In this work, the water erosion is modeled in the fluid/soil interface during the hole erosion test (HET). The Hole Erosion Test is commonly used to quantify the rate of...

In this present paper we propose a new approach for modeling a rigid multibody system based on Bond Graph methodology. The proposed method based on the transfer of energy between system components and on the description of the vector velocity relation of a moving point in a rotating system. Our mechatronic system is a double freedom robot manipulat...

CFD simulation with enhanced modeling of turbulence and near-wall treatment is used to model water–clay mixtures flowing through a cylindrical pipe domain. Effects on the wall-shear stress resulting from varying water clay content and applied hydraulic gradient are analyzed. Various parametric studies were performed and had shown that the two-dimen...

Buckling analysis of axially compressed cylindrical shells having one or two localized initial geometric imperfections was performed by using the finite element method. The imperfections of entering triangular form were assumed to be positioned symmetrically at the mid shell length. The buckling load was assessed in terms of shell aspect ratios, im...

A model for the mechanical dynamics of a wind turbine is developed, which is the composition of three physical mechanisms: flexion, torsion, and rotational dynamics. A first contribution is the identification of the essential physical parameters that provide a time-scale separation of these three mechanisms. Under the assumption of singular perturb...

The authors study the small oscillations of a pendulum containing an almost homogeneous, incompressible, inviscid liquid (i.e.
a liquid whose density in equilibrium is practically a linear function of the height, which differs very little from a constant)
and a moving gas. Using functional analysis, they prove that the spectrum is comprised of a co...

Soil erosion is a complex phenomenon which yields at its final stage insidious fluid leakages under the hydraulic infrastructures known as piping and which provokes their rupture. The Hole Erosion Test is commonly used to quantify the rate of piping erosion. In this work, The Hole Erosion Test is modelled by using Fluent package. This modelling mak...

Stability of imperfect elastic cylindrical shells which are subjected to uniform axial compression is analyzed by using the finite element method. Multiple interacting localized axisymmetric initial geometric imperfections, having either triangular or wavelet shapes, were considered. The effect of a single localized geometric imperfection was analy...

Soil erosion is a complex phenomenon which yields at its final stage insidious fluid leakages under the hydraulic infrastructures known as piping and which provokes their rupture. The Hole Erosion Test is commonly used to quantify the rate of piping erosion. In this work, The Hole Erosion Test is modelled by using Fluent package. This modelling mak...

Lifetime of a standard dog-bone specimen is assessed under the action of various thermomechanical fatigue loadings. Mechanical and thermal cycles were assumed to occur concurrently and the special effect of phasing between thermal cycles and strains cycles was emphasized. The methodology used is based on finite element post-processing analysis by s...

Abstract
This work presents a research on the jets and their industrial applications. It consists of a theoretical part, where the equations of momentum and energy conservation are presented and then simplified with adequate transformations before being solved numerically using the Range Kutta scheme of fourth order. An experimental study of impact...

Internal erosion is a process of progressive degradation which occurs in soils containing fines under the action of a flowing fluid. This phenomenon could yield catastrophic damages to hydraulic infrastructures. A generalized modelling which enables simulating internal erosion phenomenon has been proposed recently. Simulation results obtained by th...

Structural optimisation problems are very complex to solve in practice. Even in the simplest case where the shape of the structure is given and the optimisation is only about some discrete sizing variables, the associated mathematical program is very intricate to formulate since the problem lacks in general to have a closed analytical form. When an...

The authors study the small oscillations of a heavy system formed by an almost-homogeneous liquid (i.e. a liquid whose density in equilibrium is practically a linear function of the height, which differs very little from a constant) and a moving gas in a container.Using functional analysis, they prove that the spectrum is comprised of a countable s...

Problem statement: Elastic cylindrical shells are common structures in the fields of civil engineering and engineering mechanics. These thin-walled constructions may undergo buckling when subjected to axial compression. Buckling limits to large extent their strength performance. This phenomenon depends hugely on the initial distributed or localized...

Problem statement: Internal soil erosion is a real threat for hydraulic infrastructures. In its final stage it develops in piping involving the formation and progression of a continuous void inside the soil between the upstream and downstream sides. The hole erosion test was introduced to characterize kinematics of piping in terms of the time left...

Problem statement: Many modern structures are made from thin shells. Design of these elements depends to a large extent on their buckling behavior which is hugely affected by the initial geometric imperfections. Approach: For axially compressed isotropic circular cylindrical shells, axisymmetric localized geometric imperfections were found to reduc...

Modelling and simulation of wind turbines were investigated from the control point of view in order to analyse the effect of flexibility and aero elastic coupling on power extraction rate efficiency. Descriptions of aerodynamic interaction and aero elastic mechanical coupling were performed by means of simplified effective models. The main effect o...

Résumé : L'essai d'érosion de tube (Hole Erosion Test) est modélisé en utilisant le logiciel Comsol. L'écoulement fluide dans le tube est supposé être gouverné par les équations de Navier-Stokes et l'échantillon de sol est supposé obéir au système des équations de Biot qui couple l'équation de Darcy avec les déformations poroélastiques axisymétriqu...

Analyses du décollement de la couche limite d'un jet laminaire impactant sur une plaque plane chauffée : kissifst@yahoo.fr et a.draoui@uae.ma Introduction : Dans de nombreuses applications industrielles, les jets sont employés dans le but de contrôler la température de surface d'un corps par convection forcée. Lorsque qu'un jet impacte une plaque h...

El ensayo de erosión de tubo se desarrolló con el fin de estudiar el fenómeno de la erosión producida en las grietas que se hallan en determinadas obras hidráulicas como por ejemplo las presas. La prueba permite describir experimentalmente las características erosivas del suelo mediante un índice llamado velocidad de erosión y una tensión crítica q...

p. 2523-2534 The effect of two localized axisymmetric initial imperfections on the critical load of elastic cylindrical shells subjected to axial compression is studied through finite element modelling. This was carried out by means of the specialized shell buckling package Stanlax. First, a single defect having a triangular geometry is considered...

In this paper a thermo-electro-elastic modeling for piezoelectric inclusions in an infinite non-piezoelectric matrix is proposed. Extension of the heterogeneous inclusion problem of Eshelby for elastic to electroelastic behavior is formulated in terms of four interaction tensors. These tensors are basically used to derive the self-consistent model...

In this work, a modeling of electroelastic composite materials is proposed. The extension of the heterogeneous inclusion problem of Eshelby for elastic to electroelastic behavior is formulated in terms of four interaction tensors related to Eshelby’s electroelastic tensors. Analytical formulations of interaction tensors are presented for ellipsoida...

In this work, the dynamical behavior of tether connected satellites system during deployment and retrieval process is considered. The system consists of a space station connected to a subsatellite by means of a tether of variable length. A simplified model in which the space station and the subsatellite are reduced to material points and the system...

The dynamics of a tethered satellite system (TSS) during deployment and retrieval in orbit are considered. The system consists of a space station and a second body (a sub-satellite) connected to it by a tether. The station and sub-satellite are assumed to be point masses whose mass centre describes an unperturbed Kepler orbit. Deployment/retrieval...

Dynamics of a satellite cable system is studied in the processes of deployment and retrieval on the orbit. The system consists of a space station and the second body (sonde) connected with the station by a cable. The station and sonde are considered as material points and it is assumed that their mass center is moved along a non-disturbed Kepler or...

In this work, a general analytical approach for the dynamical behavior of the tether connected satellites system during deployment and retrieval processes is used. The system consists of a Space Station connected to a subsatellite by means of a straight tether of variable length. A simplified model in which the Space Station and the subsatellite ar...

On propose un modèle analytique simplifié de l’essai d’érosion de tube permettant de dégager la loi d’évolution du phénomène d’érosion de surface en fonction du régime d’écoulement. On montre que le phénomène d’érosion est gouverné par une dynamique de premier ordre où deux paramètres seulement interviennent: le temps caractéristique du phénomène l...

Le code de calcul éléments finis Stanlax est utilisé pour analyser l’effet de défauts localisés sur la charge critique de flambement dans le cas des coques cylindriques axisymétriques minces soumises à la compression axiale. Le cas d’un défaut localisé isolé a été considéré en premier lieu afin de déterminer le défaut le plus sévère et fixer les fa...