https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Fri, 06 Mar 2026 23:52:13 GMT 2026-03-06T23:52:13Z http://hdl.handle.net/10985/9971 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. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9971 2015-01-01T00:00:00Z 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. http://hdl.handle.net/10985/13276 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. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/13276 2018-01-01T00:00:00Z 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. http://hdl.handle.net/10985/14640 Multiscale physicochemical characterization of a short glass fiber–reinforced polyphenylene sulfide composite under aging and its thermo-oxidative mechanism PEIYUAN, Zuo; SHIRINBAYAN, Mohammadali; TCHARKHTCHI, Abbas; FITOUSSI, Joseph; BAKIR, Farid In this paper, the thermo-oxidation for a short glass fiber–reinforced polyphenylene sulfide (PPS/GF) composite was experimentally and theoretically studied by a wide range of physicochemical and mechanical techniques. The accelerated thermal aging temperatures were fixed at 100°C, 140°C, 160°C, 180°C, and 200°C. Firstly, the results of weight loss under aging indicate the formation of volatile products because of chain scission of end groups. Also, Fourier-transform infrared spectroscopy (FTIR) results suggest that the formation and accumulation of carbonyl group arising from the formation of hydroperoxides in oxidative propagation process. In all cases of different thermal oxidation temperatures, it is hard to observe some significant change about the concentration of carbonyl group during the induction time. This induction time depends inversely on the oxidation temperature. Moreover, the cross-linking and chain scissions exist together according to the results of rheological results and it is easier to see the cross-linking phenomenon at the beginning of oxidation while the chain scissions are more pronounced, with the oxidation process developing further. In aspect of mechanical properties, σ max increases at the beginning of oxidation because of cross-linking, and subsequently, the σ max always decreases because of thermo-oxidation of the PPS matrix. In addition, the detailed thermo-oxidation processes are fully discussed in the end of this study. A mechanistic schema has been proposed to present different oxidation reactions of PPS polymer and then a kinetic model has been extracted from this mechanism. Afterwards, the model has been verified by experimental results at different temperatures. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/14640 2019-01-01T00:00:00Z PEIYUAN, Zuo SHIRINBAYAN, Mohammadali TCHARKHTCHI, Abbas FITOUSSI, Joseph BAKIR, Farid In this paper, the thermo-oxidation for a short glass fiber–reinforced polyphenylene sulfide (PPS/GF) composite was experimentally and theoretically studied by a wide range of physicochemical and mechanical techniques. The accelerated thermal aging temperatures were fixed at 100°C, 140°C, 160°C, 180°C, and 200°C. Firstly, the results of weight loss under aging indicate the formation of volatile products because of chain scission of end groups. Also, Fourier-transform infrared spectroscopy (FTIR) results suggest that the formation and accumulation of carbonyl group arising from the formation of hydroperoxides in oxidative propagation process. In all cases of different thermal oxidation temperatures, it is hard to observe some significant change about the concentration of carbonyl group during the induction time. This induction time depends inversely on the oxidation temperature. Moreover, the cross-linking and chain scissions exist together according to the results of rheological results and it is easier to see the cross-linking phenomenon at the beginning of oxidation while the chain scissions are more pronounced, with the oxidation process developing further. In aspect of mechanical properties, σ max increases at the beginning of oxidation because of cross-linking, and subsequently, the σ max always decreases because of thermo-oxidation of the PPS matrix. In addition, the detailed thermo-oxidation processes are fully discussed in the end of this study. A mechanistic schema has been proposed to present different oxidation reactions of PPS polymer and then a kinetic model has been extracted from this mechanism. Afterwards, the model has been verified by experimental results at different temperatures. http://hdl.handle.net/10985/17639 Coupled effect of loading frequency and amplitude on the fatigue behavior of advanced sheet molding compound (A-SMC) SHIRINBAYAN, Mohammadali; FITOUSSI, Joseph; MERAGHNI, Fodil; SUROWIEC, Benjamin; LARIBI, M. A.; TCHARKHTCHI, Abbas This paper presents the experimental results of tension-tension stress-controlled fatigue tests performed on advanced sheet molding compound (A-SMC). It aims at analyzing the effect of fiber orientation, loading amplitude, and frequency on the fatigue response and the related temperature evolution due to the self-heating phenomenon. Two types of A-SMC have been analyzed: randomly oriented (RO) and highly oriented (HO). The coupled effect of the loading amplitude and the frequency has been studied. It has been shown that the couple frequency-amplitude affects the nature of the fatigue overall response which can be governed by the damage mechanisms accumulation (mechanical fatigue) and/or by the self-heating (induced thermal fatigue). For fatigue loading at 100 Hz, self-heating has been observed and yielded to a temperature rise up to 70 C. The latter causes a decrease of the storage modulus related to the b-transition of the vinylester. It has been demonstrated that the self-heating produced a material softening and decreased the fatigue life. SEM observations revealed that the samples tested at 100 Hz, exhibit smooth debonding surfaces due to the induced thermal softening of the matrix whereas more brittle fracture of the matrix surrounding fibers is observed during the fatigue tests achieved at 10 Hz. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/17639 2017-01-01T00:00:00Z SHIRINBAYAN, Mohammadali FITOUSSI, Joseph MERAGHNI, Fodil SUROWIEC, Benjamin LARIBI, M. A. TCHARKHTCHI, Abbas This paper presents the experimental results of tension-tension stress-controlled fatigue tests performed on advanced sheet molding compound (A-SMC). It aims at analyzing the effect of fiber orientation, loading amplitude, and frequency on the fatigue response and the related temperature evolution due to the self-heating phenomenon. Two types of A-SMC have been analyzed: randomly oriented (RO) and highly oriented (HO). The coupled effect of the loading amplitude and the frequency has been studied. It has been shown that the couple frequency-amplitude affects the nature of the fatigue overall response which can be governed by the damage mechanisms accumulation (mechanical fatigue) and/or by the self-heating (induced thermal fatigue). For fatigue loading at 100 Hz, self-heating has been observed and yielded to a temperature rise up to 70 C. The latter causes a decrease of the storage modulus related to the b-transition of the vinylester. It has been demonstrated that the self-heating produced a material softening and decreased the fatigue life. SEM observations revealed that the samples tested at 100 Hz, exhibit smooth debonding surfaces due to the induced thermal softening of the matrix whereas more brittle fracture of the matrix surrounding fibers is observed during the fatigue tests achieved at 10 Hz. http://hdl.handle.net/10985/17849 Multi-scale analysis of the effect of loading conditions on monotonic and fatigue behavior of a glass fiber reinforced polyphenylene sulfide (PPS) composite ZUO, Peiyuan; BENEVIDES, R.C.; LARIBI, M.A.; SHIRINBAYAN, Mohammadali; TCHARKHTCHI, Abbas; FITOUSSI, Joseph; BAKIR, Farid In this paper, two kinds of PPS/GF composite samples (PPS-0°, PPS-90°) were prepared with two different fiber main orientations related to the injection direction. A wide range of their properties were discussed. Using DMTA analysis, it was shown that the PPS/GF composite under study obeyed the time-temperature equivalence principle. Moreover, Perez model was verified and gave a good estimation of the viscoelastic properties of the PPS/GF. Monotonic and fatigue behaviors and fatigue life of PPS/GF were investigated. Fiber's orientation, applied amplitude and loading frequency effects were emphasized. Self-heating effect on fatigue strength was also analyzed. SEM fracture surface observations allowed analyzing, at the local scale, the main deformation mechanisms occurring during mechanical loading. No evident damage development was observed for both monotonic and fatigue loading. PPS matrix plasticity appeared to be the predominant deformation mechanism until a semi-ductile or semi-brittle final failure depending on the loading conditions and local microstructure. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/17849 2018-01-01T00:00:00Z ZUO, Peiyuan BENEVIDES, R.C. LARIBI, M.A. SHIRINBAYAN, Mohammadali TCHARKHTCHI, Abbas FITOUSSI, Joseph BAKIR, Farid In this paper, two kinds of PPS/GF composite samples (PPS-0°, PPS-90°) were prepared with two different fiber main orientations related to the injection direction. A wide range of their properties were discussed. Using DMTA analysis, it was shown that the PPS/GF composite under study obeyed the time-temperature equivalence principle. Moreover, Perez model was verified and gave a good estimation of the viscoelastic properties of the PPS/GF. Monotonic and fatigue behaviors and fatigue life of PPS/GF were investigated. Fiber's orientation, applied amplitude and loading frequency effects were emphasized. Self-heating effect on fatigue strength was also analyzed. SEM fracture surface observations allowed analyzing, at the local scale, the main deformation mechanisms occurring during mechanical loading. No evident damage development was observed for both monotonic and fatigue loading. PPS matrix plasticity appeared to be the predominant deformation mechanism until a semi-ductile or semi-brittle final failure depending on the loading conditions and local microstructure. http://hdl.handle.net/10985/15468 Thermal aging effects on overall mechanical behavior of short glass fiber-reinforced polyphenylene sulfide composites ZUO, Peiyuan; SHIRINBAYAN, Mohammadali; TCHARKHTCHI, Abbas; FITOUSSI, Joseph; BAKIR, Farid In this article, the overall mechanical properties of a short glass fiber-reinforced polyphenylene sulfide (PPS) composite were tested after oxidation at different temperatures (140, 160, 180, and 200°C), with a maximum oxidation time of approximately 5,300 h. In aspect of thermal aging process, the oxidation rates in 200 and 180°C are considerably harsher and faster than the case in 160 and 140°C, according to the concentration evolution of [C=O]. In aspect of mechanical properties, for virgin samples, due to an excellent fiber–matrix adhesion, no progressive damage is developed. Moreover, the fatigue results of aged samples show that the fatigue lifetime of PPS composites decreases more and more obviously with the oxidation time increasing while no significant loss of stiffness is observed. In addition, both monotonic and cyclic loadings are basically driven by the PPS matrix deformation. In the end, the relationship between fatigue lifetime and concentration of [CO] is built and discussed. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/15468 2019-01-01T00:00:00Z ZUO, Peiyuan SHIRINBAYAN, Mohammadali TCHARKHTCHI, Abbas FITOUSSI, Joseph BAKIR, Farid In this article, the overall mechanical properties of a short glass fiber-reinforced polyphenylene sulfide (PPS) composite were tested after oxidation at different temperatures (140, 160, 180, and 200°C), with a maximum oxidation time of approximately 5,300 h. In aspect of thermal aging process, the oxidation rates in 200 and 180°C are considerably harsher and faster than the case in 160 and 140°C, according to the concentration evolution of [C=O]. In aspect of mechanical properties, for virgin samples, due to an excellent fiber–matrix adhesion, no progressive damage is developed. Moreover, the fatigue results of aged samples show that the fatigue lifetime of PPS composites decreases more and more obviously with the oxidation time increasing while no significant loss of stiffness is observed. In addition, both monotonic and cyclic loadings are basically driven by the PPS matrix deformation. In the end, the relationship between fatigue lifetime and concentration of [CO] is built and discussed. http://hdl.handle.net/10985/18976 Micromechanical Modelling of Dynamic Behavior of Advanced Sheet Molding Compound (A-SMC) Composite AYARI, Houssem; SHIRINBAYAN, Mohammadali; IMADDAHEN, Amine; TAMBOURA, Sahbi; BEN DALY, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph Passive safety, particularly in the transport industry, requires maximizing the dissipation of energy and minimizing the decelerations undergone by a vehicle following a violent impact (crash). This paper proposes a strategy for identifying an anisotropic local damage criterion in a moderate dynamic loading for Advanced Sheet Molding Compound (A-SMC) composite materials. Multi-scale damage modelling based on the Mori-Tanaka approach is put forward. Previously, the results of an experimental campaign carried out on a range of strain rates varying from quasi static to 200 s−1 were used to identify a probabilistic local damage criterion based on Weibull’s formulation and integrate the effect of damage at a fiber-matrix interface scale. Therefore, the progressive local damage occurring under a fast loading may be described. A two-step homogenization procedure allows describing the strain rate effect on the stress-strain curves. The model gives also rise to the prediction of the progressive anisotropic loss of stiffness. Comparing between the experimental and numerical results confirms the ability of the proposed approach to describe the visco-damage effect (delay of damage threshold and decrease in damage kinetics) emphasized in A-SMC composites. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18976 2020-01-01T00:00:00Z AYARI, Houssem SHIRINBAYAN, Mohammadali IMADDAHEN, Amine TAMBOURA, Sahbi BEN DALY, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph Passive safety, particularly in the transport industry, requires maximizing the dissipation of energy and minimizing the decelerations undergone by a vehicle following a violent impact (crash). This paper proposes a strategy for identifying an anisotropic local damage criterion in a moderate dynamic loading for Advanced Sheet Molding Compound (A-SMC) composite materials. Multi-scale damage modelling based on the Mori-Tanaka approach is put forward. Previously, the results of an experimental campaign carried out on a range of strain rates varying from quasi static to 200 s−1 were used to identify a probabilistic local damage criterion based on Weibull’s formulation and integrate the effect of damage at a fiber-matrix interface scale. Therefore, the progressive local damage occurring under a fast loading may be described. A two-step homogenization procedure allows describing the strain rate effect on the stress-strain curves. The model gives also rise to the prediction of the progressive anisotropic loss of stiffness. Comparing between the experimental and numerical results confirms the ability of the proposed approach to describe the visco-damage effect (delay of damage threshold and decrease in damage kinetics) emphasized in A-SMC composites. http://hdl.handle.net/10985/18956 Microstructure dependent fatigue life prediction for short fibers reinforced composites: Application to sheet molding compounds LARIBI, Mohamad-Amine; TAMBOURA, Sahbi; SHIRINBAYAN, Mohammadali; BI, R.Tie; BEN DALI, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph Because of the high variability of SMC microstructure due to material flow during thermoforming, fatigue life prediction in real automotive structure represents a huge challenge. In this paper, we present a two-step microstructure selection involving an original ultrasonic method which is briefly presented. Then, on the basis of four selected microstructure configurations, an accurate experimental damage analysis is performed including both monotonic and cyclic loading. The high microstructure dependence of the obtained Whöler curves is demonstrated. Moreover, an experimental link between monotonic damage and fatigue life is emphasized. Then, a new fatigue life prediction methodology based on the later is proposed. This methodology also uses a micromechanical damage model in which a local damage criterion is involved for monotonic loading damage prediction. A very good agreement between experimental and predicted Whöler curves is demonstrated for all studied microstructures and three working temperatures. Finally, the model allows building a microstructure dependent Whöler curve abacus which may be very useful for SMC structures design. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18956 2020-01-01T00:00:00Z LARIBI, Mohamad-Amine TAMBOURA, Sahbi SHIRINBAYAN, Mohammadali BI, R.Tie BEN DALI, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph Because of the high variability of SMC microstructure due to material flow during thermoforming, fatigue life prediction in real automotive structure represents a huge challenge. In this paper, we present a two-step microstructure selection involving an original ultrasonic method which is briefly presented. Then, on the basis of four selected microstructure configurations, an accurate experimental damage analysis is performed including both monotonic and cyclic loading. The high microstructure dependence of the obtained Whöler curves is demonstrated. Moreover, an experimental link between monotonic damage and fatigue life is emphasized. Then, a new fatigue life prediction methodology based on the later is proposed. This methodology also uses a micromechanical damage model in which a local damage criterion is involved for monotonic loading damage prediction. A very good agreement between experimental and predicted Whöler curves is demonstrated for all studied microstructures and three working temperatures. Finally, the model allows building a microstructure dependent Whöler curve abacus which may be very useful for SMC structures design. http://hdl.handle.net/10985/18403 Experimental and numerical multi-scale approach for Sheet-Molding-Compound composites fatigue prediction based on fiber-matrix interface cyclic damage TAMBOURA, Sahbi; AYARI, Houssem; SHIRINBAYAN, Mohammadali; LARIBI, Mohamad-Amine; BENDALY, Hachmi; SIDHOM, Habib; TCHARKHTCHI, Abbas; FITOUSSI, Joseph In this paper, a multi-scale approach is proposed to predict the stiffness reduction of a Sheet-Molding-Compound (SMC) composite submitted to low cycle fatigue (until 2.105 cycles). Strain-controlled tensile fatigue tests (R = 0.1) are carried out at various strain ranges. Damage is investigated at both macroscopic and microscopic scales through the evolutions of Young's modulus and SEM observations, after interrupted fatigue tests at different lifetime periods. The results show that the fatigue degradation of the composite is mainly controlled by fiber-matrix interface debonding. A quantitative analysis allows determining the threshold and kinetics of the fiber-matrix interface damage during cyclic loading as a function of the orientation of fibers. Moreover, a fiber-matrix interface damage criterion, taking into account the local cyclic normal and shear stresses at the interface, is introduced in the Mori and Tanaka approach in order to predict the loss of stiffness. The parameters of this local criterion are identified by reverse engineering on the basis of the experimental results described above. Finally, the predicted loss of stiffness is very consistent with the experimental results Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/18403 2020-01-01T00:00:00Z TAMBOURA, Sahbi AYARI, Houssem SHIRINBAYAN, Mohammadali LARIBI, Mohamad-Amine BENDALY, Hachmi SIDHOM, Habib TCHARKHTCHI, Abbas FITOUSSI, Joseph In this paper, a multi-scale approach is proposed to predict the stiffness reduction of a Sheet-Molding-Compound (SMC) composite submitted to low cycle fatigue (until 2.105 cycles). Strain-controlled tensile fatigue tests (R = 0.1) are carried out at various strain ranges. Damage is investigated at both macroscopic and microscopic scales through the evolutions of Young's modulus and SEM observations, after interrupted fatigue tests at different lifetime periods. The results show that the fatigue degradation of the composite is mainly controlled by fiber-matrix interface debonding. A quantitative analysis allows determining the threshold and kinetics of the fiber-matrix interface damage during cyclic loading as a function of the orientation of fibers. Moreover, a fiber-matrix interface damage criterion, taking into account the local cyclic normal and shear stresses at the interface, is introduced in the Mori and Tanaka approach in order to predict the loss of stiffness. The parameters of this local criterion are identified by reverse engineering on the basis of the experimental results described above. Finally, the predicted loss of stiffness is very consistent with the experimental results http://hdl.handle.net/10985/17851 Implementation of surface tension force in fluid flow during reactive rotational molding HAMIDI, A.; ILLOUL, A.; SHIRINBAYAN, Mohammadali; TCHARKHTCHI, Abbas; BAKIR, Farid; KHELLADI, Sofiane During Reactive Rotational Molding (RRM), it is very important to predict the fluid flow in order to obtain the piece with homogeneous shape and high quality. This prediction may be possible by simulation the fluid flow during rotational molding. In this study we have used a mixture of isocyanate and polyol as reactive system. The kinetic rheological behaviors of thermoset polyurethane are investigated in anisothermal conditions. Thanks to these, rheokinetik model of polyurethane was identified. Then, to simulate the RRM, we have applied Smoothed Particles Hydrodynamics (SPH) method which is suited method to simulate the fluid flow with free surface such as occurs at RRM. Modelling and simulating reactive system flow depend on different parameters; one of them is the surface tension of reactive fluid. To implement force tension surface, the interface between polymer and air is dynamically tracked by finding the particles on this border. First, the boundary particles are detected by free-surface detection algorithm developed by Barecasco, Terissa and NAA [1, 2] in two and three dimension. Then, analytical and geometrical algorithms have been used for interface reconstructions. The aim of this work is the implementation of surface tension force in the SPH solver applied to RRM. To illustrate that, we used novel and simple geometric algorithm fitting circle and fitting sphere, in two and three dimensional configurations, respectively. The model has been validated using a well-known dam break test case which covered the experimental data. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/17851 2015-01-01T00:00:00Z HAMIDI, A. ILLOUL, A. SHIRINBAYAN, Mohammadali TCHARKHTCHI, Abbas BAKIR, Farid KHELLADI, Sofiane During Reactive Rotational Molding (RRM), it is very important to predict the fluid flow in order to obtain the piece with homogeneous shape and high quality. This prediction may be possible by simulation the fluid flow during rotational molding. In this study we have used a mixture of isocyanate and polyol as reactive system. The kinetic rheological behaviors of thermoset polyurethane are investigated in anisothermal conditions. Thanks to these, rheokinetik model of polyurethane was identified. Then, to simulate the RRM, we have applied Smoothed Particles Hydrodynamics (SPH) method which is suited method to simulate the fluid flow with free surface such as occurs at RRM. Modelling and simulating reactive system flow depend on different parameters; one of them is the surface tension of reactive fluid. To implement force tension surface, the interface between polymer and air is dynamically tracked by finding the particles on this border. First, the boundary particles are detected by free-surface detection algorithm developed by Barecasco, Terissa and NAA [1, 2] in two and three dimension. Then, analytical and geometrical algorithms have been used for interface reconstructions. The aim of this work is the implementation of surface tension force in the SPH solver applied to RRM. To illustrate that, we used novel and simple geometric algorithm fitting circle and fitting sphere, in two and three dimensional configurations, respectively. The model has been validated using a well-known dam break test case which covered the experimental data.