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<title>SAM</title>
<link>https://sam.ensam.eu:443</link>
<description>The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.</description>
<pubDate xmlns="http://apache.org/cocoon/i18n/2.1">Fri, 15 May 2026 23:45:34 GMT</pubDate>
<dc:date>2026-05-15T23:45:34Z</dc:date>
<item>
<title>Shape Memory Effect and Properties Memory Effect of Polyurethane</title>
<link>http://hdl.handle.net/10985/8054</link>
<description>Shape Memory Effect and Properties Memory Effect of Polyurethane
FARZANEH, Sedigheh; LUCAS, Albert; BOCQUET, Michel; TCHARKHTCHI, Abbas; FITOUSSI, Joseph
The relationship between shape and properties memory effect, especially viscoelastic properties of polyurethane under study is the main aim of this research work. Tensile tests have been performed in order to introduce 100% of deformation in the polyurethane samples. Under this deformation, stress–relaxation experiments have been performed in order to eliminate the residual stresses. This deformation of the samples has been fixed by cooling. Recovery tests, then, were carried out at different isothermal temperatures that varied from 30 C to 60  C. Viscoelastic behavior has been studied by a biparabolic model and by using the Cole–Cole method. It was shown that this model describes the behavior of the polymer at the different states of shape memory tests. The constants of this model then have been determined. This study leads to a better understanding of the mechanism of shape memory effect. The comparison between the virgin polymer and the polymer after a recovery test by DMTA (dynamic mechanical thermal analysis) and by Cole–Cole method has illustrated that the polymer does not obtain its initial properties even when it was totally regained its initial shape. These results have been confirmed by three successive shape memory tests on the same sample and by comparing the mechanical characteristics of different cycles because ‘‘shape memory effect’’ and ‘‘properties memory effect’’ do not follow the same mechanisms.
</description>
<pubDate>Tue, 01 Jan 2013 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/8054</guid>
<dc:date>2013-01-01T00:00:00Z</dc:date>
<dc:creator>FARZANEH, Sedigheh</dc:creator>
<dc:creator>LUCAS, Albert</dc:creator>
<dc:creator>BOCQUET, Michel</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:creator>FITOUSSI, Joseph</dc:creator>
<dc:description>The relationship between shape and properties memory effect, especially viscoelastic properties of polyurethane under study is the main aim of this research work. Tensile tests have been performed in order to introduce 100% of deformation in the polyurethane samples. Under this deformation, stress–relaxation experiments have been performed in order to eliminate the residual stresses. This deformation of the samples has been fixed by cooling. Recovery tests, then, were carried out at different isothermal temperatures that varied from 30 C to 60  C. Viscoelastic behavior has been studied by a biparabolic model and by using the Cole–Cole method. It was shown that this model describes the behavior of the polymer at the different states of shape memory tests. The constants of this model then have been determined. This study leads to a better understanding of the mechanism of shape memory effect. The comparison between the virgin polymer and the polymer after a recovery test by DMTA (dynamic mechanical thermal analysis) and by Cole–Cole method has illustrated that the polymer does not obtain its initial properties even when it was totally regained its initial shape. These results have been confirmed by three successive shape memory tests on the same sample and by comparing the mechanical characteristics of different cycles because ‘‘shape memory effect’’ and ‘‘properties memory effect’’ do not follow the same mechanisms.</dc:description>
</item>
<item>
<title>Oxidative solution polymerization of aniline hydrochloride onto electrospun nanofibers mats of polylactic acid: Preparation method and characterization</title>
<link>http://hdl.handle.net/10985/9267</link>
<description>Oxidative solution polymerization of aniline hydrochloride onto electrospun nanofibers mats of polylactic acid: Preparation method and characterization
AL-JALLAD, Mazen; ATASSI, Yomen; MOUNIF, Eskandar; ARESSY, Matthieu; TCHARKHTCHI, Abbas
In this work, we present the preparation of polylactic acid (PLLA)/polyaniline (PANI) conductive composite nanofibers mats. They are prepared by bulk oxidative solution polymerization of PANI onto electrospun non-woven fibers mats of PLLA. The PANI ratio in the composite is about 70%w/w. Scanning electron microscopy (SEM) shows that PLLA nanofibers are randomly oriented, beads free with diameters of 186 ± 85 nm, The PLLA/PANI composite nanofibers diameter values are 518 ± 128 nm with a good adherence between PANI and PLLA nanofibers. DSC and XRD measurements reveal an amorphous structure of the electrospun PLLA fibers due to the rapid evaporization of the solvent. FTIR and UV-vis spectra reflect good mutual interactions between PANI and PLLA chains. The DC-conductivities (σ=0.07-0.13-S.cm-1) far better than other published ones for similar composites prepared by bulk oxidative solution polymerization of PANI onto other electrospun nanofiber mats or with electrospun nanofibers from a solution mixture of PLLA and PANI.
</description>
<pubDate>Wed, 01 Jan 2014 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/9267</guid>
<dc:date>2014-01-01T00:00:00Z</dc:date>
<dc:creator>AL-JALLAD, Mazen</dc:creator>
<dc:creator>ATASSI, Yomen</dc:creator>
<dc:creator>MOUNIF, Eskandar</dc:creator>
<dc:creator>ARESSY, Matthieu</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>In this work, we present the preparation of polylactic acid (PLLA)/polyaniline (PANI) conductive composite nanofibers mats. They are prepared by bulk oxidative solution polymerization of PANI onto electrospun non-woven fibers mats of PLLA. The PANI ratio in the composite is about 70%w/w. Scanning electron microscopy (SEM) shows that PLLA nanofibers are randomly oriented, beads free with diameters of 186 ± 85 nm, The PLLA/PANI composite nanofibers diameter values are 518 ± 128 nm with a good adherence between PANI and PLLA nanofibers. DSC and XRD measurements reveal an amorphous structure of the electrospun PLLA fibers due to the rapid evaporization of the solvent. FTIR and UV-vis spectra reflect good mutual interactions between PANI and PLLA chains. The DC-conductivities (σ=0.07-0.13-S.cm-1) far better than other published ones for similar composites prepared by bulk oxidative solution polymerization of PANI onto other electrospun nanofiber mats or with electrospun nanofibers from a solution mixture of PLLA and PANI.</dc:description>
</item>
<item>
<title>Fatigue Behavior of Polyamide 66/Glass Fiber Under Various Kinds of Applied Load</title>
<link>http://hdl.handle.net/10985/10081</link>
<description>Fatigue Behavior of Polyamide 66/Glass Fiber Under Various Kinds of Applied Load
ESMAEILLOU, Bardia; FERREIRA, Paulo; BELLENGER, Véronique; TCHARKHTCHI, Abbas
In this study, the fatigue behavior of polyamide 66 reinforced with short glass fibers and especially the role of glass fibers has been investigated under two kinds of cyclic loading. tension–tension fatigue tests with stress controlled and alternative flexural fatigue test with strain controlled were carried out. The main topics include microscope damage observation, described by fiber/matrix debonding and interfacial failure, endurance limit with Wohler curves, effect of self-heating temperature. For both tests, the surface temperature increases with an increasing applied load. The results show that the self-heating has an important effect in the failure point where the Wohler curves join each other. The fracture surface was analyzed by scanning electron microscope for both applied loads. The stress ratio is −1 for alternative flexural fatigue test and 0.1 and 0.3 for tension–tension fatigue test ones at frequencies ranging 2–60 Hz.
</description>
<pubDate>Sun, 01 Jan 2012 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/10081</guid>
<dc:date>2012-01-01T00:00:00Z</dc:date>
<dc:creator>ESMAEILLOU, Bardia</dc:creator>
<dc:creator>FERREIRA, Paulo</dc:creator>
<dc:creator>BELLENGER, Véronique</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>In this study, the fatigue behavior of polyamide 66 reinforced with short glass fibers and especially the role of glass fibers has been investigated under two kinds of cyclic loading. tension–tension fatigue tests with stress controlled and alternative flexural fatigue test with strain controlled were carried out. The main topics include microscope damage observation, described by fiber/matrix debonding and interfacial failure, endurance limit with Wohler curves, effect of self-heating temperature. For both tests, the surface temperature increases with an increasing applied load. The results show that the self-heating has an important effect in the failure point where the Wohler curves join each other. The fracture surface was analyzed by scanning electron microscope for both applied loads. The stress ratio is −1 for alternative flexural fatigue test and 0.1 and 0.3 for tension–tension fatigue test ones at frequencies ranging 2–60 Hz.</dc:description>
</item>
<item>
<title>Fatigue Damage Initiation of a PA66/Glass Fibers Composite Material</title>
<link>http://hdl.handle.net/10985/10083</link>
<description>Fatigue Damage Initiation of a PA66/Glass Fibers Composite Material
ESMAEILLOU, Bardia; FEREIRRA, P; BELLENGER, Véronique; TCHARKHTCHI, Abbas
Fatigue damage initiation of a PA66/glass fiber composite material is studied with interrupted tests carried out with an “alternative bending device” and a small applied strain. During the damage initiation period, no change of macroscopic properties, density, cristallinity ratio, glass transition temperature, and flexural elastic modulus is observed. Polysequential tests are carried out with three rest times differing by their length. These rest times allow the relaxation of macromolecular chains in the region of the microdefects and increase the number of cycles at fracture. The most efficient stop is the one just before the final fracture. The comparison of the fatigue behavior of the composite and its neat matrix shows that the microdefects relaxed during the break are identical to those which initiate damage and final fracture.
</description>
<pubDate>Sun, 01 Jan 2012 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/10083</guid>
<dc:date>2012-01-01T00:00:00Z</dc:date>
<dc:creator>ESMAEILLOU, Bardia</dc:creator>
<dc:creator>FEREIRRA, P</dc:creator>
<dc:creator>BELLENGER, Véronique</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>Fatigue damage initiation of a PA66/glass fiber composite material is studied with interrupted tests carried out with an “alternative bending device” and a small applied strain. During the damage initiation period, no change of macroscopic properties, density, cristallinity ratio, glass transition temperature, and flexural elastic modulus is observed. Polysequential tests are carried out with three rest times differing by their length. These rest times allow the relaxation of macromolecular chains in the region of the microdefects and increase the number of cycles at fracture. The most efficient stop is the one just before the final fracture. The comparison of the fatigue behavior of the composite and its neat matrix shows that the microdefects relaxed during the break are identical to those which initiate damage and final fracture.</dc:description>
</item>
<item>
<title>Rotational Moulding of Thermosets: Understanding of a Reactive Forming Process</title>
<link>http://hdl.handle.net/10985/6474</link>
<description>Rotational Moulding of Thermosets: Understanding of a Reactive Forming Process
VIALE, Jérémy; NONY, Fabien; MAZABRAUD, Philippe; GERARD, Jean-François; DOULIN, Gwenaël; TCHARKHTCHI, Abbas
Physical and chemical transformations of polyurethane thermoset are studied by means of thermal analysis, infrared spectrophotometer and dynamic rheology. Gel point, which limits the material flow, is given as a function of conversion and as a function of time by kinetic law. Glass transition corresponding to a dramatic transformation of the material is also explored and connected to conversion and time. These ex situ characterizations are then exploited in terms of rotational moulding process parameters to improve the understanding and thus the control of the process. Therefore in situ thermal analyses are handled to confirm first results. Final parts thickness distribution is examined as a quantitative parameter of process quality. Finally, as a perspective, ultrasonic response is also studied as a new way to follow material evolution directly in the forming mould.
L'auteur Abbas TCHARKHTCHI faisait parti en 2008 du Laboratoire d’Ingénierie des Matériaux (LIM). Depuis 2010, le LIM a fusionné avec deux autres unités de recherche en un seul laboratoire intitulé PIMM (Procédés et Ingénierie en Mécanique et Matériaux). Il fait parti du groupe de recherche : Procédés et Performance des Polymères et Composites.
</description>
<pubDate>Tue, 01 Jan 2008 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/6474</guid>
<dc:date>2008-01-01T00:00:00Z</dc:date>
<dc:creator>VIALE, Jérémy</dc:creator>
<dc:creator>NONY, Fabien</dc:creator>
<dc:creator>MAZABRAUD, Philippe</dc:creator>
<dc:creator>GERARD, Jean-François</dc:creator>
<dc:creator>DOULIN, Gwenaël</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>Physical and chemical transformations of polyurethane thermoset are studied by means of thermal analysis, infrared spectrophotometer and dynamic rheology. Gel point, which limits the material flow, is given as a function of conversion and as a function of time by kinetic law. Glass transition corresponding to a dramatic transformation of the material is also explored and connected to conversion and time. These ex situ characterizations are then exploited in terms of rotational moulding process parameters to improve the understanding and thus the control of the process. Therefore in situ thermal analyses are handled to confirm first results. Final parts thickness distribution is examined as a quantitative parameter of process quality. Finally, as a perspective, ultrasonic response is also studied as a new way to follow material evolution directly in the forming mould.</dc:description>
</item>
<item>
<title>Thermal Aging Effect on Mechanical Properties of Polyurethane</title>
<link>http://hdl.handle.net/10985/9892</link>
<description>Thermal Aging Effect on Mechanical Properties of Polyurethane
FARZANEH, Sedigheh; ABDALLAH-ELHIRTSI, Sofiane; ESMAEILLOU, Bardia; NONY, Fabien; BARON, A; TCHARKHTCHI, Abbas
This study concerns the effect of thermal aging on mechanical properties of polyurethane. Polyurethane samples were exposed at 85° and 120°C under inert atmosphere. Mechanical tests were carried out on these samples the aging period. Tensile tests were performed to see the effect of aging on elastic modulus (E), stress (σr), and strain (ϵr) at break. It was shown that there are two distinct periods. Due to aging, E and σr increase in the first period, then they decrease in the second period. ϵr decreases first and then increases. Fatigue tests were performed on unaged and aged samples. It was shown that the fatigue behavior of polyurethane (PU) is improved the same way during the first stage of aging. In the second step, the number of cycles to failure increases due to aging. The results show that aging has an important effect on mechanical properties of PU. The strain at break decreases during the first step of aging due to post-cross-linking and then increases due to chain scission in the network. Based on these results, the effect of cross-linking and chain scission on the mechanical properties of PU was discussed.
</description>
<pubDate>Wed, 01 Jan 2014 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/9892</guid>
<dc:date>2014-01-01T00:00:00Z</dc:date>
<dc:creator>FARZANEH, Sedigheh</dc:creator>
<dc:creator>ABDALLAH-ELHIRTSI, Sofiane</dc:creator>
<dc:creator>ESMAEILLOU, Bardia</dc:creator>
<dc:creator>NONY, Fabien</dc:creator>
<dc:creator>BARON, A</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>This study concerns the effect of thermal aging on mechanical properties of polyurethane. Polyurethane samples were exposed at 85° and 120°C under inert atmosphere. Mechanical tests were carried out on these samples the aging period. Tensile tests were performed to see the effect of aging on elastic modulus (E), stress (σr), and strain (ϵr) at break. It was shown that there are two distinct periods. Due to aging, E and σr increase in the first period, then they decrease in the second period. ϵr decreases first and then increases. Fatigue tests were performed on unaged and aged samples. It was shown that the fatigue behavior of polyurethane (PU) is improved the same way during the first stage of aging. In the second step, the number of cycles to failure increases due to aging. The results show that aging has an important effect on mechanical properties of PU. The strain at break decreases during the first step of aging due to post-cross-linking and then increases due to chain scission in the network. Based on these results, the effect of cross-linking and chain scission on the mechanical properties of PU was discussed.</dc:description>
</item>
<item>
<title>High strain rate visco-damageable behavior of Advanced Sheet Molding Compound (A-SMC) under tension</title>
<link>http://hdl.handle.net/10985/9971</link>
<description>High strain rate visco-damageable behavior of Advanced Sheet Molding Compound (A-SMC) under tension
SHIRINBAYAN, Mohammadali; FITOUSSI, Joseph; MERAGHNI, Fodil; SUROWIEC, Benjamin; BOCQUET, Michel; TCHARKHTCHI, Abbas
Advanced Sheet Molding Compound (A-SMC) is a serious composite material candidate for structural automotive parts. It has a thermoset matrix and consists of high weight  content of glass fibers (50% in mass) compared to standard SMC with less than 30% weight fiber content. During crash events, structural parts are heavily exposed to high rates of loading and straining. This work is concerned with the development of an advanced experimental approach devoted to the micro and macroscopic characterization of A-SMC mechanical behavior under high-speed tension. High speed tensile tests are achieved using servo-hydraulic test equipment in order to get required high strain rates up to 100 s 1. Local deformation is measured through a contactless technique using a high speed camera. Numerical computations have led to an optimal design of the specimen geometry and the experimental damping systems have been optimized in terms of thickness and material properties. These simulations were achieved using ABAQUS explicit finite element code. The developed experimental methodology is applied for two types of A-SMC: Randomly Oriented (RO) and Highly Oriented (HO) plates. In the case of HO samples, two tensile directions were chosen: HO-0  (parallel to the Mold Flow Direction (MFD)) and HO-90  (perpendicular to the MFD). High speed tensile tests results show that A-SMC behavior is strongly strain-rate dependent although the Young's modulus remains constant with increasing strain rate. In the case of HO-0 , the stress damage threshold is shown an increase of 63%, when the strain rate varies from quasi-static (0.001 s 1) to 100 s 1. The experimental methodology was coupled to microscopic observations using SEM. Damage mechanisms investigation of HO and RO specimens showed a competition between two mechanisms: fiber-matrix interface debonding and pseudo-delamination between neighboring bundles of fibers. It is shown that pseudo-delamination cannot be neglected. In fact, this mechanism can greatly participate to energy absorption during crash. Moreover, the influence of fiber orientation and imposed velocity is studied. It is shown that high strain rate and oriented fiber in the tensile direction favor the pseudo-delamination.
</description>
<pubDate>Thu, 01 Jan 2015 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/9971</guid>
<dc:date>2015-01-01T00:00:00Z</dc:date>
<dc:creator>SHIRINBAYAN, Mohammadali</dc:creator>
<dc:creator>FITOUSSI, Joseph</dc:creator>
<dc:creator>MERAGHNI, Fodil</dc:creator>
<dc:creator>SUROWIEC, Benjamin</dc:creator>
<dc:creator>BOCQUET, Michel</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>Advanced Sheet Molding Compound (A-SMC) is a serious composite material candidate for structural automotive parts. It has a thermoset matrix and consists of high weight  content of glass fibers (50% in mass) compared to standard SMC with less than 30% weight fiber content. During crash events, structural parts are heavily exposed to high rates of loading and straining. This work is concerned with the development of an advanced experimental approach devoted to the micro and macroscopic characterization of A-SMC mechanical behavior under high-speed tension. High speed tensile tests are achieved using servo-hydraulic test equipment in order to get required high strain rates up to 100 s 1. Local deformation is measured through a contactless technique using a high speed camera. Numerical computations have led to an optimal design of the specimen geometry and the experimental damping systems have been optimized in terms of thickness and material properties. These simulations were achieved using ABAQUS explicit finite element code. The developed experimental methodology is applied for two types of A-SMC: Randomly Oriented (RO) and Highly Oriented (HO) plates. In the case of HO samples, two tensile directions were chosen: HO-0  (parallel to the Mold Flow Direction (MFD)) and HO-90  (perpendicular to the MFD). High speed tensile tests results show that A-SMC behavior is strongly strain-rate dependent although the Young's modulus remains constant with increasing strain rate. In the case of HO-0 , the stress damage threshold is shown an increase of 63%, when the strain rate varies from quasi-static (0.001 s 1) to 100 s 1. The experimental methodology was coupled to microscopic observations using SEM. Damage mechanisms investigation of HO and RO specimens showed a competition between two mechanisms: fiber-matrix interface debonding and pseudo-delamination between neighboring bundles of fibers. It is shown that pseudo-delamination cannot be neglected. In fact, this mechanism can greatly participate to energy absorption during crash. Moreover, the influence of fiber orientation and imposed velocity is studied. It is shown that high strain rate and oriented fiber in the tensile direction favor the pseudo-delamination.</dc:description>
</item>
<item>
<title>Experimental study of the miscibility of ABS/PC polymer blends and investigation of the processing effect</title>
<link>http://hdl.handle.net/10985/12275</link>
<description>Experimental study of the miscibility of ABS/PC polymer blends and investigation of the processing effect
AID, Sara; EDDHAHAK, Anissa; ORTEGA, Zaida; FROELICH, Daniel; TCHARKHTCHI, Abbas
In the challenging prospect of developing new materials by mixing different polymers to reach a synergetic performance, the present research focuses on the study of the miscibility of two polymers: The acrylonitrile butadiene styrene (ABS) composed of a dispersed elastomeric (polybutadiene rubber) polymer embedded in a SAN thermoplastic matrix, and the polycarbonate (PC). It shall be noted that obtaining miscible polymer blends is often a difficult task because of the large size of their molecular chains and the high interfacial tension between the polymer phases. Until now, the most numerous researches developed in this field involve polymer blends obtained by compatibilization techniques in order to improve the interfacial adhesion between initial polymers. The aim of this work is to study the miscibility between ABS and PC. First, two different methods were used to mix the polymers: the twin-screw extrusion and the dissolution in a common solvent tetrahydrofuran (THF). Then, physicochemical, microscopic observation and rheological characterization were performed on samples of mixtures obtained by both extrusion processing and dissolution method. The measurement of glassy transition temperature (Tg) by differential scanning calorimetry measurements (DSC) and dynamical mechanical thermal analysis (DMTA) have shown a partial miscibility between the two polymers.
</description>
<pubDate>Sun, 01 Jan 2017 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/12275</guid>
<dc:date>2017-01-01T00:00:00Z</dc:date>
<dc:creator>AID, Sara</dc:creator>
<dc:creator>EDDHAHAK, Anissa</dc:creator>
<dc:creator>ORTEGA, Zaida</dc:creator>
<dc:creator>FROELICH, Daniel</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>In the challenging prospect of developing new materials by mixing different polymers to reach a synergetic performance, the present research focuses on the study of the miscibility of two polymers: The acrylonitrile butadiene styrene (ABS) composed of a dispersed elastomeric (polybutadiene rubber) polymer embedded in a SAN thermoplastic matrix, and the polycarbonate (PC). It shall be noted that obtaining miscible polymer blends is often a difficult task because of the large size of their molecular chains and the high interfacial tension between the polymer phases. Until now, the most numerous researches developed in this field involve polymer blends obtained by compatibilization techniques in order to improve the interfacial adhesion between initial polymers. The aim of this work is to study the miscibility between ABS and PC. First, two different methods were used to mix the polymers: the twin-screw extrusion and the dissolution in a common solvent tetrahydrofuran (THF). Then, physicochemical, microscopic observation and rheological characterization were performed on samples of mixtures obtained by both extrusion processing and dissolution method. The measurement of glassy transition temperature (Tg) by differential scanning calorimetry measurements (DSC) and dynamical mechanical thermal analysis (DMTA) have shown a partial miscibility between the two polymers.</dc:description>
</item>
<item>
<title>Influence of loading conditions on the overall mechanical behavior of polyether-ether-ketone (PEEK)</title>
<link>http://hdl.handle.net/10985/13276</link>
<description>Influence of loading conditions on the overall mechanical behavior of polyether-ether-ketone (PEEK)
ABBASNEZHAD, Navideh; KHAVANDI, Alireza; ARABI, Hossein; SHIRINBAYAN, Mohammadali; TCHARKHTCHI, Abbas; FITOUSSI, Joseph
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.
</description>
<pubDate>Mon, 01 Jan 2018 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/13276</guid>
<dc:date>2018-01-01T00:00:00Z</dc:date>
<dc:creator>ABBASNEZHAD, Navideh</dc:creator>
<dc:creator>KHAVANDI, Alireza</dc:creator>
<dc:creator>ARABI, Hossein</dc:creator>
<dc:creator>SHIRINBAYAN, Mohammadali</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:creator>FITOUSSI, Joseph</dc:creator>
<dc:description>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.</dc:description>
</item>
<item>
<title>Thermal aging kinetic and effects on mechanical behavior of fully recycled composite based on polypropylene/polyethylene blend</title>
<link>http://hdl.handle.net/10985/13817</link>
<description>Thermal aging kinetic and effects on mechanical behavior of fully recycled composite based on polypropylene/polyethylene blend
TAMBOURA, Sahbi; BENDALY, Hachmi; FITOUSSI, Jean Paul; MEFTAH, Hicham; TCHARKHTCHI, Abbas
The effect of thermal oxidation of a fully recycled carbon fibers reinforced stabilized polypropylene/polyethylene blend on the mechanical properties has been studied at 120, 130 and 140 °C. In a first step, several analyses by FTIR and UV spectrometry and differential scanning calorimetry were performed in order to detect and monitor the evolution of the antioxidants and oxidation products in the materials. This approach aims to well understand and identify the aging mechanisms that will be modeled in a second step in a kinetic model capable of predicting the evolution of carbonyl build-up while taking into account the presence of the different antioxidants. Modeling results showed a good correlation between the kinetic behavior and the obtained experimental data. Furthermore, the effect of thermal aging on the mechanical behaviors of the composite and the matrix were studied at the macroscopic scale at different strain rates. It has been shown that the thermal oxidation affects only the elongation at break. The numerical values of the oxidation products generated by the kinetic model allowed linking the evolution of the mechanical behavior under aging with the physicochemical state of the material.
</description>
<pubDate>Mon, 01 Jan 2018 00:00:00 GMT</pubDate>
<guid isPermaLink="false">http://hdl.handle.net/10985/13817</guid>
<dc:date>2018-01-01T00:00:00Z</dc:date>
<dc:creator>TAMBOURA, Sahbi</dc:creator>
<dc:creator>BENDALY, Hachmi</dc:creator>
<dc:creator>FITOUSSI, Jean Paul</dc:creator>
<dc:creator>MEFTAH, Hicham</dc:creator>
<dc:creator>TCHARKHTCHI, Abbas</dc:creator>
<dc:description>The effect of thermal oxidation of a fully recycled carbon fibers reinforced stabilized polypropylene/polyethylene blend on the mechanical properties has been studied at 120, 130 and 140 °C. In a first step, several analyses by FTIR and UV spectrometry and differential scanning calorimetry were performed in order to detect and monitor the evolution of the antioxidants and oxidation products in the materials. This approach aims to well understand and identify the aging mechanisms that will be modeled in a second step in a kinetic model capable of predicting the evolution of carbonyl build-up while taking into account the presence of the different antioxidants. Modeling results showed a good correlation between the kinetic behavior and the obtained experimental data. Furthermore, the effect of thermal aging on the mechanical behaviors of the composite and the matrix were studied at the macroscopic scale at different strain rates. It has been shown that the thermal oxidation affects only the elongation at break. The numerical values of the oxidation products generated by the kinetic model allowed linking the evolution of the mechanical behavior under aging with the physicochemical state of the material.</dc:description>
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