M. Boutaous - Academia.edu (original) (raw)
Papers by M. Boutaous
Volume 1C, Symposia: Fundamental Issues and Perspectives in Fluid Mechanics; Industrial and Environmental Applications of Fluid Mechanics; Issues and Perspectives in Automotive Flows; Gas-Solid Flows: Dedicated to the Memory of Professor Clayton T. Crowe; Numerical Methods for Multiphase Flow; Tr..., 2014
ABSTRACT
Volume 7: Fluids Engineering Systems and Technologies, 2014
PLA (Poly Lactic Acid) is a bio-sourced and biodegradable polymer. It represents an alternative f... more PLA (Poly Lactic Acid) is a bio-sourced and biodegradable polymer. It represents an alternative for polymers issued from petrochemical synthesis. Unfortunately, the crystallization kinetics of PLA is very slow and limits the possibility to extend its application in several industrials domains. The enhancement of the PLA crystallization kinetic can be obtained by addition of nucleating agents of by ordering the molecular chains during flow, as in processing conditions. During processing of thermoplastic polymer experiences several thermomechanical conditions influencing drastically its final properties and mechanical behavior. During injection molding process, macromolecules are oriented and ordered due to the shear and elongation imposed by the melt flow in the mold during the filling step. As a consequence, supplementary nucleation is created in the polymer, leading to the acceleration of the crystallization kinetics. In this work, we propose to analyze and to quantify the role of ...
Journal of Fluids Engineering, 2004
The general framework deals with the winding of thin plastic films, in order to obtain good-quali... more The general framework deals with the winding of thin plastic films, in order to obtain good-quality rolls. This issue is tightly connected to the thickness of the residual air layer entrapped between the film layers. It is then of importance to optimize the surface topography of the films so that to improve the quality of the wound rolls. In a previous work, we proposed a simple model for the flow of an air layer squeezed between a solid smooth substrate and a plastic film sample: it was shown experimentally that the macroscopic characteristics of the flow are connected to the film roughness, but how? In order to answer this question, we assimilated the confined air flow to a flow through a periodic array of cylinders and a mathematical model based on homogenization techniques was developed. In the present paper, we search for pertinent parameters which describe the real surface roughness of plastic films. The experiments were carried out by using a 3-D roughness measurement device ...
International journal of multiphase flow, 2005
A level set technique for interface tracking is presented, both for the continuum surface force f... more A level set technique for interface tracking is presented, both for the continuum surface force formulation and the ghost fluid method approach. A projection method is used to solve incompressible Navier-Stokes equations that are coupled to a transport equation for the level set function, defined as the algebraic distance to interface. Results are presented for head-on droplet collisions in coalescence and reflexive regimes with a 2D axi-symmetric code, and for an off-center droplet collision in a separation regime for a large impact parameter with 3D code. Simulations provided realistic and various droplet collision behaviors and they correspond to experimental observations.
Comptes Rendus Mécanique, 2010
During the cooling stage in several types polymer processing, the behavior of the polymer is very... more During the cooling stage in several types polymer processing, the behavior of the polymer is very difficult to model and to simulate numerically, because of the complicated coupling between the crystallization process, the heat transfer and the material properties change. The aim of this Note is the numerical simulation of the coupling phenomena between the crystallization rate and the thermal kinetics in a semi-crystalline polymer during cooling without flow, by using Finite Elements Method.
18ème Congrès …, 2007
18?me Congr?s Fran?ais de M?canique Grenoble, 27-31 ao?t 2007 1 Simulation du refroidissement iso... more 18?me Congr?s Fran?ais de M?canique Grenoble, 27-31 ao?t 2007 1 Simulation du refroidissement isochore d?un polym?re semi-cristallin : prise en compte du diagramme PVT Matthieu Zinet 1, Nadia Brahmia 1, M?hamed Boutaous 1, Patrice Chantrenne 1, Patrick Bourgin ...
A Numerical Model for Non-Isothermal Flow Induced Crystallization in Thermoplastic Polymers. [ASM... more A Numerical Model for Non-Isothermal Flow Induced Crystallization in Thermoplastic Polymers. [ASME Conference Proceedings 2009, 23 (2009)]. Matthieu Zinet, Rabie El Otmani, M'hamed Boutaous, Patrice Chantrenne. Abstract. ...
Page n° 1 Juillet 2005 Numerical Simulation of the Filling Stage in the Polymer Injection Mouldin... more Page n° 1 Juillet 2005 Numerical Simulation of the Filling Stage in the Polymer Injection Moulding Process -Conference COMSOL 2007 - R. El Otmani, M. Zinet, M. Boutaous, P. Chantrenne and H. Ben Hadid Contact: Rabie.el-otmani@insa-lyon.fr Page 2. Page n° 2 Juillet 2005 ...
Journal of Non-Newtonian Fluid Mechanics, 2010
Concentrated suspension theory Heat transfer Modelling the two driving causes is presented and di... more Concentrated suspension theory Heat transfer Modelling the two driving causes is presented and discussed: at low cooling rate or at high temperature, the shearing effect predominates. Other interesting results show the size distribution of the spherulites as well as the volume proportion for each crystalline size in the polymer.
Volume 7A: Fluids Engineering Systems and Technologies, 2013
ABSTRACT The variation of the microstructure within the thickness of moulding plates of two semic... more ABSTRACT The variation of the microstructure within the thickness of moulding plates of two semicrystalline polymers, an isotactic Poly-Propylene and a Poly-Butylene Terephtalate, was observed by optical microscopy technique. These observations allowed specifying the different zones of iso-microstructure within the plate thickness, commonly called “skin zone”, “shear zone”, “post filling zone ”and“ core zone”in terms of crystallite size and zone thickness. The variation of the melting temperature was then analysed by using a local thermal analysis method based on the scanning thermal microscopy technique in each of these zones. Our results show the expected link between the local microstructure and the polymer melting temperature. They also highlight a strong coupling between the microstructure, the material and its processing conditions.
Polymers Advanced Technologies, 2021
The dependence of the induced morphological layer variations on the processing conditions and par... more The dependence of the induced morphological layer variations on the processing conditions and parameters during injection molding of polymers is analyzed through a robust numerical framework of the complete microinjection molding cycle. Predicted temperature, heat transfer and viscous dissipation, spherulite diameters, and shear rates provide sufficient clarifications to develop a deeper understanding of the complex evolution of the induced thicknesses of layers. The evolution of the structure of polyoxymethylene (POM) under strong strain rates and high thermal gradients is investigated while flowing along an expanding flow configuration composed of three steps of increasing thickness. High and low mold temperatures and injection velocity levels are tested according to the design of the experiment method (DOE). Morphological development in each zone was examined to provide the induced crystalline layer thickness in the longitudinal as well as the transverse directions using polarized light microscopy (PLM). The thickness of the layers strongly depends on the local thickness of the stepped-part and on the abrupt dimensional changes. The variation of bulk tensile properties obtained by dynamic mechanical analysis (DMA) is related to the thermomechanical history experienced by the melt.
K E Y W O R D S layer thickness development, microinjection molding, morphology, numerical modeling, tensile tests
Conference: ASME 2016 International Mechanical Engineering Congress and Exposition, November 11-17, 2016 at: Phoenix, Arizona, USA, 2016
Processing conditions of polymers governs the final part properties; in fact the thermomechanical... more Processing conditions of polymers governs the final part properties; in fact the thermomechanical history subjected by the polymer affects directly the crystalline microstructure and the crystallinity. In this work we aim to draw a global view about the crystallization kinetics and crystalline morphology of Polylactide (PLA). Unfortunately, the crystallization kinetics of PLA is very slow and limits the possibility to extend its application in several industrials domains. The enhancement of the PLA crystallization kinetic can be obtained by addition of nucleating agents of by ordering the molecular chains during flow, as in processing conditions. In this paper, we propose to highlight the competition between several parameters, as the shear rate, the temperature kinetics and the shearing time.
Conference: ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels at: Washington, DC, USA, Volume: 2; Paper No. HT2016-1070, pp. V002T22A003, 2016
As well known, the selective laser Sintering (SLS) is one of the most modern and innovative addit... more As well known, the selective laser Sintering (SLS) is one of the most modern and innovative additive manufacturing technologies with general advantages and wide applications, as a non-contact process, which is flexible, and easily controlled. The choice of process parameters is quite important for laser melting in metallic powder bed. When these parameters are not correctly chosen, particles are either not sintering at all or joining into rather large droplets. This process is named as balling phenomenon, which is extremely unfavorable. In this paper, a 3D numerical model based on discrete element method is proposed in order to study the effect of parameters on the generation of balling droplets in laser melting process. A complex model is developed which couples all phenomena of full SLS process and results of simulations are compared with experimental works of other researchers taken from the literature.
Afin de simuler numériquement le procédé d'injection, il est nécessaire de prendre en compte ... more Afin de simuler numériquement le procédé d'injection, il est nécessaire de prendre en compte la phase de refroidissement et de solidification du matériau. Dans le cas d'un polymère semi-cristallin comme le polypropylène, l'existence d'un couplage fort entre les transferts thermiques, la cristallisation, la compressibilité ainsi que l'évolution des caractéristiques thermophysiques du matériau accroissent la complexité des calculs. Dans cette étude, après une détermination expérimentale des propriétés thermophysiques du matériau, une modélisation du refroidissement isochore d'un polymère tenant compte du comportement pression-volume-température (PVT) est présentée. Le modèle introduit un couplage entre tous ces phénomènes et permet de calculer l'évolution de la pression, de la température, de la cristallinité relative et du volume spécifique local dans la cavité du moule à partir d'une pression initiale élevée jusqu'à la pression atmosphérique et le...
Volume 1C, Symposia: Fundamental Issues and Perspectives in Fluid Mechanics; Industrial and Environmental Applications of Fluid Mechanics; Issues and Perspectives in Automotive Flows; Gas-Solid Flows: Dedicated to the Memory of Professor Clayton T. Crowe; Numerical Methods for Multiphase Flow; Tr..., 2014
ABSTRACT
Volume 7: Fluids Engineering Systems and Technologies, 2014
PLA (Poly Lactic Acid) is a bio-sourced and biodegradable polymer. It represents an alternative f... more PLA (Poly Lactic Acid) is a bio-sourced and biodegradable polymer. It represents an alternative for polymers issued from petrochemical synthesis. Unfortunately, the crystallization kinetics of PLA is very slow and limits the possibility to extend its application in several industrials domains. The enhancement of the PLA crystallization kinetic can be obtained by addition of nucleating agents of by ordering the molecular chains during flow, as in processing conditions. During processing of thermoplastic polymer experiences several thermomechanical conditions influencing drastically its final properties and mechanical behavior. During injection molding process, macromolecules are oriented and ordered due to the shear and elongation imposed by the melt flow in the mold during the filling step. As a consequence, supplementary nucleation is created in the polymer, leading to the acceleration of the crystallization kinetics. In this work, we propose to analyze and to quantify the role of ...
Journal of Fluids Engineering, 2004
The general framework deals with the winding of thin plastic films, in order to obtain good-quali... more The general framework deals with the winding of thin plastic films, in order to obtain good-quality rolls. This issue is tightly connected to the thickness of the residual air layer entrapped between the film layers. It is then of importance to optimize the surface topography of the films so that to improve the quality of the wound rolls. In a previous work, we proposed a simple model for the flow of an air layer squeezed between a solid smooth substrate and a plastic film sample: it was shown experimentally that the macroscopic characteristics of the flow are connected to the film roughness, but how? In order to answer this question, we assimilated the confined air flow to a flow through a periodic array of cylinders and a mathematical model based on homogenization techniques was developed. In the present paper, we search for pertinent parameters which describe the real surface roughness of plastic films. The experiments were carried out by using a 3-D roughness measurement device ...
International journal of multiphase flow, 2005
A level set technique for interface tracking is presented, both for the continuum surface force f... more A level set technique for interface tracking is presented, both for the continuum surface force formulation and the ghost fluid method approach. A projection method is used to solve incompressible Navier-Stokes equations that are coupled to a transport equation for the level set function, defined as the algebraic distance to interface. Results are presented for head-on droplet collisions in coalescence and reflexive regimes with a 2D axi-symmetric code, and for an off-center droplet collision in a separation regime for a large impact parameter with 3D code. Simulations provided realistic and various droplet collision behaviors and they correspond to experimental observations.
Comptes Rendus Mécanique, 2010
During the cooling stage in several types polymer processing, the behavior of the polymer is very... more During the cooling stage in several types polymer processing, the behavior of the polymer is very difficult to model and to simulate numerically, because of the complicated coupling between the crystallization process, the heat transfer and the material properties change. The aim of this Note is the numerical simulation of the coupling phenomena between the crystallization rate and the thermal kinetics in a semi-crystalline polymer during cooling without flow, by using Finite Elements Method.
18ème Congrès …, 2007
18?me Congr?s Fran?ais de M?canique Grenoble, 27-31 ao?t 2007 1 Simulation du refroidissement iso... more 18?me Congr?s Fran?ais de M?canique Grenoble, 27-31 ao?t 2007 1 Simulation du refroidissement isochore d?un polym?re semi-cristallin : prise en compte du diagramme PVT Matthieu Zinet 1, Nadia Brahmia 1, M?hamed Boutaous 1, Patrice Chantrenne 1, Patrick Bourgin ...
A Numerical Model for Non-Isothermal Flow Induced Crystallization in Thermoplastic Polymers. [ASM... more A Numerical Model for Non-Isothermal Flow Induced Crystallization in Thermoplastic Polymers. [ASME Conference Proceedings 2009, 23 (2009)]. Matthieu Zinet, Rabie El Otmani, M'hamed Boutaous, Patrice Chantrenne. Abstract. ...
Page n° 1 Juillet 2005 Numerical Simulation of the Filling Stage in the Polymer Injection Mouldin... more Page n° 1 Juillet 2005 Numerical Simulation of the Filling Stage in the Polymer Injection Moulding Process -Conference COMSOL 2007 - R. El Otmani, M. Zinet, M. Boutaous, P. Chantrenne and H. Ben Hadid Contact: Rabie.el-otmani@insa-lyon.fr Page 2. Page n° 2 Juillet 2005 ...
Journal of Non-Newtonian Fluid Mechanics, 2010
Concentrated suspension theory Heat transfer Modelling the two driving causes is presented and di... more Concentrated suspension theory Heat transfer Modelling the two driving causes is presented and discussed: at low cooling rate or at high temperature, the shearing effect predominates. Other interesting results show the size distribution of the spherulites as well as the volume proportion for each crystalline size in the polymer.
Volume 7A: Fluids Engineering Systems and Technologies, 2013
ABSTRACT The variation of the microstructure within the thickness of moulding plates of two semic... more ABSTRACT The variation of the microstructure within the thickness of moulding plates of two semicrystalline polymers, an isotactic Poly-Propylene and a Poly-Butylene Terephtalate, was observed by optical microscopy technique. These observations allowed specifying the different zones of iso-microstructure within the plate thickness, commonly called “skin zone”, “shear zone”, “post filling zone ”and“ core zone”in terms of crystallite size and zone thickness. The variation of the melting temperature was then analysed by using a local thermal analysis method based on the scanning thermal microscopy technique in each of these zones. Our results show the expected link between the local microstructure and the polymer melting temperature. They also highlight a strong coupling between the microstructure, the material and its processing conditions.
Polymers Advanced Technologies, 2021
The dependence of the induced morphological layer variations on the processing conditions and par... more The dependence of the induced morphological layer variations on the processing conditions and parameters during injection molding of polymers is analyzed through a robust numerical framework of the complete microinjection molding cycle. Predicted temperature, heat transfer and viscous dissipation, spherulite diameters, and shear rates provide sufficient clarifications to develop a deeper understanding of the complex evolution of the induced thicknesses of layers. The evolution of the structure of polyoxymethylene (POM) under strong strain rates and high thermal gradients is investigated while flowing along an expanding flow configuration composed of three steps of increasing thickness. High and low mold temperatures and injection velocity levels are tested according to the design of the experiment method (DOE). Morphological development in each zone was examined to provide the induced crystalline layer thickness in the longitudinal as well as the transverse directions using polarized light microscopy (PLM). The thickness of the layers strongly depends on the local thickness of the stepped-part and on the abrupt dimensional changes. The variation of bulk tensile properties obtained by dynamic mechanical analysis (DMA) is related to the thermomechanical history experienced by the melt.
K E Y W O R D S layer thickness development, microinjection molding, morphology, numerical modeling, tensile tests
Conference: ASME 2016 International Mechanical Engineering Congress and Exposition, November 11-17, 2016 at: Phoenix, Arizona, USA, 2016
Processing conditions of polymers governs the final part properties; in fact the thermomechanical... more Processing conditions of polymers governs the final part properties; in fact the thermomechanical history subjected by the polymer affects directly the crystalline microstructure and the crystallinity. In this work we aim to draw a global view about the crystallization kinetics and crystalline morphology of Polylactide (PLA). Unfortunately, the crystallization kinetics of PLA is very slow and limits the possibility to extend its application in several industrials domains. The enhancement of the PLA crystallization kinetic can be obtained by addition of nucleating agents of by ordering the molecular chains during flow, as in processing conditions. In this paper, we propose to highlight the competition between several parameters, as the shear rate, the temperature kinetics and the shearing time.
Conference: ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels at: Washington, DC, USA, Volume: 2; Paper No. HT2016-1070, pp. V002T22A003, 2016
As well known, the selective laser Sintering (SLS) is one of the most modern and innovative addit... more As well known, the selective laser Sintering (SLS) is one of the most modern and innovative additive manufacturing technologies with general advantages and wide applications, as a non-contact process, which is flexible, and easily controlled. The choice of process parameters is quite important for laser melting in metallic powder bed. When these parameters are not correctly chosen, particles are either not sintering at all or joining into rather large droplets. This process is named as balling phenomenon, which is extremely unfavorable. In this paper, a 3D numerical model based on discrete element method is proposed in order to study the effect of parameters on the generation of balling droplets in laser melting process. A complex model is developed which couples all phenomena of full SLS process and results of simulations are compared with experimental works of other researchers taken from the literature.
Afin de simuler numériquement le procédé d'injection, il est nécessaire de prendre en compte ... more Afin de simuler numériquement le procédé d'injection, il est nécessaire de prendre en compte la phase de refroidissement et de solidification du matériau. Dans le cas d'un polymère semi-cristallin comme le polypropylène, l'existence d'un couplage fort entre les transferts thermiques, la cristallisation, la compressibilité ainsi que l'évolution des caractéristiques thermophysiques du matériau accroissent la complexité des calculs. Dans cette étude, après une détermination expérimentale des propriétés thermophysiques du matériau, une modélisation du refroidissement isochore d'un polymère tenant compte du comportement pression-volume-température (PVT) est présentée. Le modèle introduit un couplage entre tous ces phénomènes et permet de calculer l'évolution de la pression, de la température, de la cristallinité relative et du volume spécifique local dans la cavité du moule à partir d'une pression initiale élevée jusqu'à la pression atmosphérique et le...