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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Fri, 15 Feb 2019 01:11:05 GMT2019-02-15T01:11:05ZTorsional Vibrations of Fluid-Filled Multilayered Transversely Isotropic Finite Circular Cylinder
http://hdl.handle.net/10985/11186
Torsional Vibrations of Fluid-Filled Multilayered Transversely Isotropic Finite Circular Cylinder
ABASSI, Wafik; EL BAROUDI, Adil; RAZAFIMAHERY, Fulgence
An analytical and numerical study for the torsional vibrations of viscous fluid-filled three-layer transversely isotropic cylinder is presented in this paper. The equations of motion of solid and fluid are respectively formulated using the constitutive equations of a transversely isotropic cylinder and the constitutive equations of a viscous fluid. The analytical solution of the frequency equation is obtained using the boundary conditions at the free surface of the solid layer and the boundary conditions at the fluid–solid interface. The frequency equation is deduced and analytically solved using the symbolic Software Mathematica. The finite element method using Comsol Multiphysics Software results are compared with present method for validation and an acceptable match between them were obtained. It is shown that the results from the proposed method are in good agreement with numerical solutions. The influence of fluid dynamic viscosity is thoroughly analyzed and the effect of the isotropic properties on the natural frequencies is also investigated.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/111862016-01-01T00:00:00ZABASSI, WafikEL BAROUDI, AdilRAZAFIMAHERY, FulgenceAn analytical and numerical study for the torsional vibrations of viscous fluid-filled three-layer transversely isotropic cylinder is presented in this paper. The equations of motion of solid and fluid are respectively formulated using the constitutive equations of a transversely isotropic cylinder and the constitutive equations of a viscous fluid. The analytical solution of the frequency equation is obtained using the boundary conditions at the free surface of the solid layer and the boundary conditions at the fluid–solid interface. The frequency equation is deduced and analytically solved using the symbolic Software Mathematica. The finite element method using Comsol Multiphysics Software results are compared with present method for validation and an acceptable match between them were obtained. It is shown that the results from the proposed method are in good agreement with numerical solutions. The influence of fluid dynamic viscosity is thoroughly analyzed and the effect of the isotropic properties on the natural frequencies is also investigated.Vibration Analysis of Euler-Bernoulli Beams Partially Immersed in a Viscous Fluid
http://hdl.handle.net/10985/11185
Vibration Analysis of Euler-Bernoulli Beams Partially Immersed in a Viscous Fluid
ABASSI, Wafik; EL BAROUDI, Adil; RAZAFIMAHERY, Fulgence
The vibrational characteristics of a microbeam are well known to strongly depend on the fluid in which the beam is immersed. In this paper, we present a detailed theoretical study of the modal analysis of microbeams partially immersed in a viscous fluid. A fixed-free microbeamvibrating in a viscous fluid is modeled using the Euler-Bernoulli equation for the beams.The unsteady Stokes equations are solved using a Helmholtz decomposition technique in a two-dimensional plane containing the microbeams cross sections.The symbolic softwareMathematica is used in order to find the coupled vibration frequencies of beams with two portions. The frequency equation is deduced and analytically solved.The finite element method using ComsolMultiphysics software results is compared with present method for validation and an acceptable match between them was obtained. In the eigenanalysis, the frequency equation is generated by satisfying all boundary conditions. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/111852016-01-01T00:00:00ZABASSI, WafikEL BAROUDI, AdilRAZAFIMAHERY, FulgenceThe vibrational characteristics of a microbeam are well known to strongly depend on the fluid in which the beam is immersed. In this paper, we present a detailed theoretical study of the modal analysis of microbeams partially immersed in a viscous fluid. A fixed-free microbeamvibrating in a viscous fluid is modeled using the Euler-Bernoulli equation for the beams.The unsteady Stokes equations are solved using a Helmholtz decomposition technique in a two-dimensional plane containing the microbeams cross sections.The symbolic softwareMathematica is used in order to find the coupled vibration frequencies of beams with two portions. The frequency equation is deduced and analytically solved.The finite element method using ComsolMultiphysics software results is compared with present method for validation and an acceptable match between them was obtained. In the eigenanalysis, the frequency equation is generated by satisfying all boundary conditions. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy.Comparaison des actionneurs
http://hdl.handle.net/10985/9238
Comparaison des actionneurs
ABBA, Gabriel
Les objectifs de ce rapport sont donc multiples. En premier, le rapport établie la méthodologie de sélection des actionneurs d’un robot en fonction d’un ou plusieurs critères à satisfaire tout en respectant les contraintes nécessaires au bon fonctionnement du robot, contraintes elles mêmes liées très fortement aux performances dynamiques exigées du robot et aux différentes tâches auxquelles le robot est destiné. Il est facile de montrer que la sélection des actionneurs est fortement liée aux choix technologiques des dispositifs de transmission des mouvements et de la technologie même desdits actionneurs. Le second objectif du rapport est par conséquent d’élaborer une méthode de sélection couplée des actionneurs et des transmissions. Pour se faire, nous limitons délibérément les choix à certaines technologies. Enfin, le dernier objectif du rapport est de proposer un modèle physique approché mais néanmoins le plus précis possible du comportement énergétique de l’ensemble de la chaîne de transmission des mouvements et donc un modèle énergétique des actionneurs, des transmissions cinématiques jusqu’aux variables articulaires du robot.
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/92382012-01-01T00:00:00ZABBA, GabrielLes objectifs de ce rapport sont donc multiples. En premier, le rapport établie la méthodologie de sélection des actionneurs d’un robot en fonction d’un ou plusieurs critères à satisfaire tout en respectant les contraintes nécessaires au bon fonctionnement du robot, contraintes elles mêmes liées très fortement aux performances dynamiques exigées du robot et aux différentes tâches auxquelles le robot est destiné. Il est facile de montrer que la sélection des actionneurs est fortement liée aux choix technologiques des dispositifs de transmission des mouvements et de la technologie même desdits actionneurs. Le second objectif du rapport est par conséquent d’élaborer une méthode de sélection couplée des actionneurs et des transmissions. Pour se faire, nous limitons délibérément les choix à certaines technologies. Enfin, le dernier objectif du rapport est de proposer un modèle physique approché mais néanmoins le plus précis possible du comportement énergétique de l’ensemble de la chaîne de transmission des mouvements et donc un modèle énergétique des actionneurs, des transmissions cinématiques jusqu’aux variables articulaires du robot.Design Elements for high speed SRM
http://hdl.handle.net/10985/11995
Design Elements for high speed SRM
ABBA, Gabriel; ANTOINE, Jean-François; SAUVEY, Christophe; VISA, Codrut
This paper deals with the study of high speed switched reluctance motors and their pre-dimensioning. The predimensioning is tackled towards the inductance profile and the torque generation. Then, the power density is assessed in terms of three defined fundamental parameters, each depending on electrical, mechanical and geometrical design of the motor. The mechanical limitations studied are the centrifugal stresses and the vibratory behavior of the motor. A shape optimization of the rotor teeth leans then on a coupled magnetic-mechanic coupled problem, solved with finite elements simulations. After that,mechanic, magnetic and copper losses are given in terms of the rotor external volume so as to assess the weight of each heat source in the global motor heating. Once all the losses are linked to temperature, a criterion to improve the ability to develop a high speed motor is finally proposed.
Thu, 01 Jan 2004 00:00:00 GMThttp://hdl.handle.net/10985/119952004-01-01T00:00:00ZABBA, GabrielANTOINE, Jean-FrançoisSAUVEY, ChristopheVISA, CodrutThis paper deals with the study of high speed switched reluctance motors and their pre-dimensioning. The predimensioning is tackled towards the inductance profile and the torque generation. Then, the power density is assessed in terms of three defined fundamental parameters, each depending on electrical, mechanical and geometrical design of the motor. The mechanical limitations studied are the centrifugal stresses and the vibratory behavior of the motor. A shape optimization of the rotor teeth leans then on a coupled magnetic-mechanic coupled problem, solved with finite elements simulations. After that,mechanic, magnetic and copper losses are given in terms of the rotor external volume so as to assess the weight of each heat source in the global motor heating. Once all the losses are linked to temperature, a criterion to improve the ability to develop a high speed motor is finally proposed.A numerical approach of two-phase non-Darcy flow in heterogeneous porous media
http://hdl.handle.net/10985/9982
A numerical approach of two-phase non-Darcy flow in heterogeneous porous media
ABBASIAN ARANI, Ali Akbar; AHMADI-SENICHAULT, Azita; LASSEUX, Didier
Significant inertial effects are observed for many applications such as flow in the near-wellbore region, in very permeable reservoirs or in packed-bed reactors. In these cases, the classical description of two-phase flow in porous media by the generalized Darcy's law is no longer valid. Due to the lack of a formalized theoretical model confirmed experimentally, our study is based on a generalized Darcy-Forchheimer approach for modelling two-phase incompressible inertial flow in porous media. Using a finite volume formulation, an IMPES (IMplicit for Pressures, Explicit for Saturations) scheme and a Fixed Point method for the treatment of non-linearities caused by inertia, a 3D numerical tool has been developed. For 1D flow in a homogeneous porous medium, comparison of saturation profiles obtained numerically at different times to those obtained semi-analytically using an “Inertial Buckley-Leverett model” allows a validation of the tool. The influence of inertial effects on the saturation profiles and therefore on the breakthrough curves for homogeneous media is analysed for different Reynolds numbers, thus emphasizing the necessity of taking into account this additional energy loss when necessary. For 1D heterogeneous configurations, a thorough analysis of the saturation fronts as well as the saturation jumps at the interface between two media of contrasted properties highlights the influence of inertial effects for different Reynolds and capillary numbers. In 2D heterogeneous configurations, saturation distributions are strongly affected by inertial effects. In particular, capillary trapping of the displaced fluid observed for the Darcy regime in certain regions can completely disappears when inertial effects become dominant.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/99822009-01-01T00:00:00ZABBASIAN ARANI, Ali AkbarAHMADI-SENICHAULT, AzitaLASSEUX, DidierSignificant inertial effects are observed for many applications such as flow in the near-wellbore region, in very permeable reservoirs or in packed-bed reactors. In these cases, the classical description of two-phase flow in porous media by the generalized Darcy's law is no longer valid. Due to the lack of a formalized theoretical model confirmed experimentally, our study is based on a generalized Darcy-Forchheimer approach for modelling two-phase incompressible inertial flow in porous media. Using a finite volume formulation, an IMPES (IMplicit for Pressures, Explicit for Saturations) scheme and a Fixed Point method for the treatment of non-linearities caused by inertia, a 3D numerical tool has been developed. For 1D flow in a homogeneous porous medium, comparison of saturation profiles obtained numerically at different times to those obtained semi-analytically using an “Inertial Buckley-Leverett model” allows a validation of the tool. The influence of inertial effects on the saturation profiles and therefore on the breakthrough curves for homogeneous media is analysed for different Reynolds numbers, thus emphasizing the necessity of taking into account this additional energy loss when necessary. For 1D heterogeneous configurations, a thorough analysis of the saturation fronts as well as the saturation jumps at the interface between two media of contrasted properties highlights the influence of inertial effects for different Reynolds and capillary numbers. In 2D heterogeneous configurations, saturation distributions are strongly affected by inertial effects. In particular, capillary trapping of the displaced fluid observed for the Darcy regime in certain regions can completely disappears when inertial effects become dominant.Derivation of a macroscopic model for two-phase non-Darcy flow in homogeneous porous media using volume averaging
http://hdl.handle.net/10985/9981
Derivation of a macroscopic model for two-phase non-Darcy flow in homogeneous porous media using volume averaging
ABBASIAN ARANI, Ali Akbar; LASSEUX, Didier; AHMADI-SENICHAULT, Azita
The purpose of this work is to propose a derivation of a macroscopic model for a certain class of inertial two-phase, incompressible, Newtonian fluid flow through homogenous porous media. The starting point of the procedure is the pore-scale boundary value problem given by the continuity and Navier–Stokes equations in each phase β and γ along with boundary conditions at interfaces. The method of volume averaging is employed subjected to a series of constraints for the development to hold. These constraints are on the length- and time-scales, as well as, on some quantities involving capillary, Weber and Reynolds numbers that define the class of two-phase flow under consideration. The development also assumes that fluctuations of the curvature of the fluid–fluid interfaces are unimportant over the unit cell representing the porous medium. Under these circumstances, the resulting macroscopic momentum equation, for the -phase (=, ) relates the gradient of the phase-averaged pressure to the filtration or Darcy velocity in a coupled nonlinear form. All tensors appearing in the macroscopic equation can be determined from closure problems that are to be solved using a spatially periodic model of a porous medium. Some indications to compute these tensors are provided.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/99812009-01-01T00:00:00ZABBASIAN ARANI, Ali AkbarLASSEUX, DidierAHMADI-SENICHAULT, AzitaThe purpose of this work is to propose a derivation of a macroscopic model for a certain class of inertial two-phase, incompressible, Newtonian fluid flow through homogenous porous media. The starting point of the procedure is the pore-scale boundary value problem given by the continuity and Navier–Stokes equations in each phase β and γ along with boundary conditions at interfaces. The method of volume averaging is employed subjected to a series of constraints for the development to hold. These constraints are on the length- and time-scales, as well as, on some quantities involving capillary, Weber and Reynolds numbers that define the class of two-phase flow under consideration. The development also assumes that fluctuations of the curvature of the fluid–fluid interfaces are unimportant over the unit cell representing the porous medium. Under these circumstances, the resulting macroscopic momentum equation, for the -phase (=, ) relates the gradient of the phase-averaged pressure to the filtration or Darcy velocity in a coupled nonlinear form. All tensors appearing in the macroscopic equation can be determined from closure problems that are to be solved using a spatially periodic model of a porous medium. Some indications to compute these tensors are provided.A numerical analysis of the inertial correction to Darcy's law
http://hdl.handle.net/10985/9980
A numerical analysis of the inertial correction to Darcy's law
ABBASIAN ARANI, Ali Akbar; LASSEUX, Didier; AHMADI-SENICHAULT, Azita
Our interest in this work is the stationary one-phase Newtonian flow in a class of homogeneous porous media at large enough flow rates so that the relationship between the filtration velocity and the pressure gradient is no longer linear. The non linear -inertial- correction to Darcy's law is investigated from a numerical point of view on model periodic structures made of regular arrays of cylinders. The starting point of the analysis is the macroscopic model resulting from the volume averaging of the mass and momentum (Navier-Stokes) equations at the pore scale. Identification of the macroscopic properties in this model is made by first solving the microscopic flow as well as the closure problem resulting from the upscaling. From these solutions, the inertial correction is computed and analyzed with respect to the Reynolds number and the pressure gradient orientation relative to the principal axes of the periodic unit cell.
Thu, 01 Jan 2009 00:00:00 GMThttp://hdl.handle.net/10985/99802009-01-01T00:00:00ZABBASIAN ARANI, Ali AkbarLASSEUX, DidierAHMADI-SENICHAULT, AzitaOur interest in this work is the stationary one-phase Newtonian flow in a class of homogeneous porous media at large enough flow rates so that the relationship between the filtration velocity and the pressure gradient is no longer linear. The non linear -inertial- correction to Darcy's law is investigated from a numerical point of view on model periodic structures made of regular arrays of cylinders. The starting point of the analysis is the macroscopic model resulting from the volume averaging of the mass and momentum (Navier-Stokes) equations at the pore scale. Identification of the macroscopic properties in this model is made by first solving the microscopic flow as well as the closure problem resulting from the upscaling. From these solutions, the inertial correction is computed and analyzed with respect to the Reynolds number and the pressure gradient orientation relative to the principal axes of the periodic unit cell.Résolution numérique de l’écoulement diphasique en milieu poreux hétérogène incluant les effets inertiels
http://hdl.handle.net/10985/10029
Résolution numérique de l’écoulement diphasique en milieu poreux hétérogène incluant les effets inertiels
ABBASIAN ARANI, Ali Akbar; LASSEUX, Didier; AHMADI-SENICHAULT, Azita
La mise en place d'un outil numérique 3D de simulation d'écoulement diphasique hors régime de Darcy basé sur le modèle de Darcy-Forchheimer généralisé est présentée. L'outil est tout d’abord validé à l’aide d'une solution semi analytique 1D de type Buckley-Leverett. Des résultats obtenus dans différentes configurations homogène et hétérogènes 1D et 2D mettent en évidence l'importance des termes inertiels en fonction d'un nombre de Reynolds de l'écoulement.
Mon, 01 Jan 2007 00:00:00 GMThttp://hdl.handle.net/10985/100292007-01-01T00:00:00ZABBASIAN ARANI, Ali AkbarLASSEUX, DidierAHMADI-SENICHAULT, AzitaLa mise en place d'un outil numérique 3D de simulation d'écoulement diphasique hors régime de Darcy basé sur le modèle de Darcy-Forchheimer généralisé est présentée. L'outil est tout d’abord validé à l’aide d'une solution semi analytique 1D de type Buckley-Leverett. Des résultats obtenus dans différentes configurations homogène et hétérogènes 1D et 2D mettent en évidence l'importance des termes inertiels en fonction d'un nombre de Reynolds de l'écoulement.Influence of loading conditions on the overall mechanical behavior of polyether-ether-ketone (PEEK)
http://hdl.handle.net/10985/13276
Influence of loading conditions on the overall mechanical behavior of polyether-ether-ketone (PEEK)
ABBASNEZHAD, N; KHAVANDI, A; FITOUSSI, JOSEPH; ARABI, H; SHIRINBAYAN, M; TCHARKHTCHI, Abbas
Testing methods have been developed to compare the mechanical responses and failure behavior of polyether-ether-keton (PEEK) thermoplastic polymer; under quasi-static, high strain rate tensile tests and fatigue loading. Tensile tests were performed with the strain rates varying from 0.0003 s−1 to 60 s−1 and at different temperatures to compare the flow characteristics of the samples undergone various testing conditions. Fatigue tests at different amplitudes and frequencies were also performed to evaluate the temperature rise during cyclic loading and its effect on the fracture behavior. Results show that dynamic tension, in comparison with quasi-static behavior, causes brittle fracture; whereas under fatigue test at high frequencies and loading amplitudes the material behaves not only a more ductile behavior but also it clearly shows the influences of induced self-heating in the modulus and mechanical properties of the PEEK were significant. So the major aim of this article is to discuss about the induced temperature and its effect on the fracture surface. Thermal fatigue has a very significant role in increasing temperature and reducing fatigue life; from there it is necessary to know the conditions at which thermal fatigue happens and also the amount of energy which is consumed. Obtained equation from the experimental results and calculations can estimate the energy dissipation in the fatigue tests which is as a function of cycle and frequency.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/132762018-01-01T00:00:00ZABBASNEZHAD, NKHAVANDI, AFITOUSSI, JOSEPHARABI, HSHIRINBAYAN, MTCHARKHTCHI, AbbasTesting methods have been developed to compare the mechanical responses and failure behavior of polyether-ether-keton (PEEK) thermoplastic polymer; under quasi-static, high strain rate tensile tests and fatigue loading. Tensile tests were performed with the strain rates varying from 0.0003 s−1 to 60 s−1 and at different temperatures to compare the flow characteristics of the samples undergone various testing conditions. Fatigue tests at different amplitudes and frequencies were also performed to evaluate the temperature rise during cyclic loading and its effect on the fracture behavior. Results show that dynamic tension, in comparison with quasi-static behavior, causes brittle fracture; whereas under fatigue test at high frequencies and loading amplitudes the material behaves not only a more ductile behavior but also it clearly shows the influences of induced self-heating in the modulus and mechanical properties of the PEEK were significant. So the major aim of this article is to discuss about the induced temperature and its effect on the fracture surface. Thermal fatigue has a very significant role in increasing temperature and reducing fatigue life; from there it is necessary to know the conditions at which thermal fatigue happens and also the amount of energy which is consumed. Obtained equation from the experimental results and calculations can estimate the energy dissipation in the fatigue tests which is as a function of cycle and frequency.Study of partial shape memory effect of polymers by multicycle tests
http://hdl.handle.net/10985/10180
Study of partial shape memory effect of polymers by multicycle tests
ABDALLAH-ELHIRTSI, Sofiane; FITOUSSI, Joseph; RASHMI, Baralu-Jagannatha; PRASHANTHA, Kalappa; FARZANEH, Sedigheh; LACRAMPE, Marie-France; KRAWCZAK, Patricia; TCHARKHTCHI, Abbas
In this work, an experimental investigation on a partial shape memory polymer (PSMP) which is transformed into shape memory material is presented. Multicycle shape memory tests are performed on thermoplastic polyurethane (TPU) at 70°C. At the end of each cycle, the capacity of the shape memory material increases. At the end of the first cycle, the recovery rate of TPU is only 67%; this partial shape memory effect (PSME) has been improved by successive cycles of shape memory tests. After the fourth cycle, it becomes nearly 100% shape memory material. The results of the fifth and sixth cycles confirm this modification. These original results indicate that a polymer with partial shape memory may be transformed into an SMP without any chemical modification. This increase of SME could be related to the creation of residual stresses during the tensile tests. The residual stresses are the origin of the driving force responsible for SME.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/101802015-01-01T00:00:00ZABDALLAH-ELHIRTSI, SofianeFITOUSSI, JosephRASHMI, Baralu-JagannathaPRASHANTHA, KalappaFARZANEH, SedighehLACRAMPE, Marie-FranceKRAWCZAK, PatriciaTCHARKHTCHI, AbbasIn this work, an experimental investigation on a partial shape memory polymer (PSMP) which is transformed into shape memory material is presented. Multicycle shape memory tests are performed on thermoplastic polyurethane (TPU) at 70°C. At the end of each cycle, the capacity of the shape memory material increases. At the end of the first cycle, the recovery rate of TPU is only 67%; this partial shape memory effect (PSME) has been improved by successive cycles of shape memory tests. After the fourth cycle, it becomes nearly 100% shape memory material. The results of the fifth and sixth cycles confirm this modification. These original results indicate that a polymer with partial shape memory may be transformed into an SMP without any chemical modification. This increase of SME could be related to the creation of residual stresses during the tensile tests. The residual stresses are the origin of the driving force responsible for SME.