https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Tue, 16 Jun 2026 00:06:03 GMT 2026-06-16T00:06:03Z http://hdl.handle.net/10985/13817 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. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/13817 2018-01-01T00:00:00Z 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. http://hdl.handle.net/10985/13302 Fast fatigue life prediction of short fiber reinforced composites using a new hybrid damage approach: Application to SMC LARIBI, Mohamad-Amine; TAMBOURA, Sahbi; BEN DALI, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph Industrial design of Short Fiber Reinforced Composites (SFRC) structures is subject to several compounding and processing steps of optimization. Moreover, these structures are often submitted to fatigue loading. Therefore, SN curves have to be established for each new composite formulation and for several type of microstructure involved in the real component due to processing. While these preliminary characterizations are time and money consuming, this paper propose a new hybrid methodology for fast fatigue life prediction. Moreover, both monotonic and fatigue behavior of SMC composites is essentially determined by local damage propagation. Therefore, the key idea of the proposed approach is to use a Mori and Tanaka based micromechanical model in order to establish an equation of state relating local damage rate to macroscopic residual stiffness rate. The generalization of this relation to fatigue damage multi-scale description leads to the SN curve fast determination of each considered microstructure. Very limited experimental characterization is required in such a way that SN curve could be established in just one day. Comparison between experimental and simulated Whöler curves highlights a very good agreement for several microstructure configurations in the case of a SMC composite material. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/13302 2018-01-01T00:00:00Z LARIBI, Mohamad-Amine TAMBOURA, Sahbi BEN DALI, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph Industrial design of Short Fiber Reinforced Composites (SFRC) structures is subject to several compounding and processing steps of optimization. Moreover, these structures are often submitted to fatigue loading. Therefore, SN curves have to be established for each new composite formulation and for several type of microstructure involved in the real component due to processing. While these preliminary characterizations are time and money consuming, this paper propose a new hybrid methodology for fast fatigue life prediction. Moreover, both monotonic and fatigue behavior of SMC composites is essentially determined by local damage propagation. Therefore, the key idea of the proposed approach is to use a Mori and Tanaka based micromechanical model in order to establish an equation of state relating local damage rate to macroscopic residual stiffness rate. The generalization of this relation to fatigue damage multi-scale description leads to the SN curve fast determination of each considered microstructure. Very limited experimental characterization is required in such a way that SN curve could be established in just one day. Comparison between experimental and simulated Whöler curves highlights a very good agreement for several microstructure configurations in the case of a SMC composite material. http://hdl.handle.net/10985/15738 Characterization of a New Fully Recycled Carbon Fiber Reinforced Composite Subjected to High Strain Rate Tension MEFTAH, Hassen; TAMBOURA, Sahbi; BENDALY, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph The aim of this study is the complete physicochemical characterization and strain rate effect multi-scale analysis of a new fully recycled carbon fiber reinforced composites for automotive crash application. Two composites made of 20% wt short recycled carbon fibers (CF) are obtained by injection molding. The morphology and the degree of dispersion of CF in the matrixes were examined using a new ultrasonic method and SEM. High strain tensile behavior up to 100 s-1 is investigated. In order to avoid perturbation due to inertial effect and wave propagation, the specimen geometry was optimized. The elastic properties appear to be insensitive to the strain rate. However, a high strain rate effect on the local visco-plasticity of the matrix and fiber/matrix interface visco-damageable behavior is emphasized. The predominant damage mechanisms evolve from generalized matrix local ductility at low strain rate regime to fiber/matrix interface debonding and fibers pull-out at high strain rate regime. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10985/15738 2017-01-01T00:00:00Z MEFTAH, Hassen TAMBOURA, Sahbi BENDALY, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph The aim of this study is the complete physicochemical characterization and strain rate effect multi-scale analysis of a new fully recycled carbon fiber reinforced composites for automotive crash application. Two composites made of 20% wt short recycled carbon fibers (CF) are obtained by injection molding. The morphology and the degree of dispersion of CF in the matrixes were examined using a new ultrasonic method and SEM. High strain tensile behavior up to 100 s-1 is investigated. In order to avoid perturbation due to inertial effect and wave propagation, the specimen geometry was optimized. The elastic properties appear to be insensitive to the strain rate. However, a high strain rate effect on the local visco-plasticity of the matrix and fiber/matrix interface visco-damageable behavior is emphasized. The predominant damage mechanisms evolve from generalized matrix local ductility at low strain rate regime to fiber/matrix interface debonding and fibers pull-out at high strain rate regime. 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/10985/17952 Bi-phasic water diffusion in sheet molding compound composite ABDESSALEM, Abir; TAMBOURA, Sahbi; BEN DALY, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph Sheet molding compound (SMC) composite has been studied under humid-aging conditions. Diffusion of water within the material, as measured by gravimetry, was found to be in good agreement with the “Langmuir-type” diffusion model developed by Carter and Kibler. In their theory, Carter and Kibler consider the existence of two types of water molecules in the material, «mobile» and «bound». In this study, these two types have been considered separately. Furthermore, Infrared spectroscopy (FTIR) analysis has been performed by decomposition of signals to study the fraction of free (mobile) and hydrogen-bounded water. Thermal analysis and microscopic observations were put forward to explain the two types of water molecules. In this contribution, we found a “bi-phasic” water diffusion. We suggest that the «mobile» water corresponding to the diffusion in the micro-porosities follows a Fickien kinetic, which turns to sigmoidal one at a specific time of immersion τ. Whereas the kinetic of «bound» water, referring to crosslinking and plasticization, follows a sigmoidal kinetic, which turns to Fickien behavior when the overall network is saturated. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/17952 2020-01-01T00:00:00Z ABDESSALEM, Abir TAMBOURA, Sahbi BEN DALY, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph Sheet molding compound (SMC) composite has been studied under humid-aging conditions. Diffusion of water within the material, as measured by gravimetry, was found to be in good agreement with the “Langmuir-type” diffusion model developed by Carter and Kibler. In their theory, Carter and Kibler consider the existence of two types of water molecules in the material, «mobile» and «bound». In this study, these two types have been considered separately. Furthermore, Infrared spectroscopy (FTIR) analysis has been performed by decomposition of signals to study the fraction of free (mobile) and hydrogen-bounded water. Thermal analysis and microscopic observations were put forward to explain the two types of water molecules. In this contribution, we found a “bi-phasic” water diffusion. We suggest that the «mobile» water corresponding to the diffusion in the micro-porosities follows a Fickien kinetic, which turns to sigmoidal one at a specific time of immersion τ. Whereas the kinetic of «bound» water, referring to crosslinking and plasticization, follows a sigmoidal kinetic, which turns to Fickien behavior when the overall network is saturated. http://hdl.handle.net/10985/17715 Thermal aging influence on the damage mechanisms of fully recycled composite-reinforced polypropylene/polyethylene blend MEFTAH, Hassen; TAMBOURA, Sahbi; BENDALY, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph The main aim of this work is to study the effect of thermal aging on damage mechanisms of a totally recycled composite. The studied material was elaborated by injection molding from a mixture of both recycled matrix (polypropylene-polyethylene blend) and reinforcement (short carbon fibers). Damage mechanisms analysis was carried out using scanning electron microscope (in situ three point bending tests performed on specimens taken at different times of oxidation under different temperatures: 120, 130, and 140°C. Damage mechanisms were identified for different material states. It was shown that thermal aging affects the fiber–matrix interfacial zone while good adhesion between the reinforcement and the matrix was observed for the virgin sample. Furthermore, a quantitative analysis was performed at the local scale in a representative zone of the tensile area. Representative local damage indicators were defined. Results display clearly that damage evolutions always begin during the induction period. Thermal aging effect was then analyzed through the comparison of damage thresholds and kinetics for different material states after different times of oxidation. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/17715 2019-01-01T00:00:00Z MEFTAH, Hassen TAMBOURA, Sahbi BENDALY, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph The main aim of this work is to study the effect of thermal aging on damage mechanisms of a totally recycled composite. The studied material was elaborated by injection molding from a mixture of both recycled matrix (polypropylene-polyethylene blend) and reinforcement (short carbon fibers). Damage mechanisms analysis was carried out using scanning electron microscope (in situ three point bending tests performed on specimens taken at different times of oxidation under different temperatures: 120, 130, and 140°C. Damage mechanisms were identified for different material states. It was shown that thermal aging affects the fiber–matrix interfacial zone while good adhesion between the reinforcement and the matrix was observed for the virgin sample. Furthermore, a quantitative analysis was performed at the local scale in a representative zone of the tensile area. Representative local damage indicators were defined. Results display clearly that damage evolutions always begin during the induction period. Thermal aging effect was then analyzed through the comparison of damage thresholds and kinetics for different material states after different times of oxidation. http://hdl.handle.net/10985/19993 Two Hybrid Approaches to Fatigue Modeling of Advanced-Sheet Molding Compounds (A-SMC) Composite AYARI, Houssem; IMADDAHEN, Amine; TAMBOURA, Sahbi; SHIRINBAYAN, Mohammadali; BEN DALI, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph To reinforce the environmental standards, we need to strengthen the lightening of vehicles and to generalize new composite materials in order to reduce weight. To use these innovative composite materials in the mass production of automotive parts, it is essential to propose a predictive approach of the S-N curves, which must be established for each new composite formulation and for several types of microstructure within real components. Although these preliminary characterizations consume time and money, this paper proposes two hybrid methodologies to predict the fatigue life during the fatigue test. Both methodologies are based on micromechanical modeling which is developed under monotonous loading with fatigue effects under different amplitudes. The suggested methodology is based on an experimental analysis of monotonic behavior under fatigue loading and on multi-scale modeling of damage. In the results, the proposed model and the used approaches are in good agreement with the experimental results. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19993 2020-01-01T00:00:00Z AYARI, Houssem IMADDAHEN, Amine TAMBOURA, Sahbi SHIRINBAYAN, Mohammadali BEN DALI, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph To reinforce the environmental standards, we need to strengthen the lightening of vehicles and to generalize new composite materials in order to reduce weight. To use these innovative composite materials in the mass production of automotive parts, it is essential to propose a predictive approach of the S-N curves, which must be established for each new composite formulation and for several types of microstructure within real components. Although these preliminary characterizations consume time and money, this paper proposes two hybrid methodologies to predict the fatigue life during the fatigue test. Both methodologies are based on micromechanical modeling which is developed under monotonous loading with fatigue effects under different amplitudes. The suggested methodology is based on an experimental analysis of monotonic behavior under fatigue loading and on multi-scale modeling of damage. In the results, the proposed model and the used approaches are in good agreement with the experimental results. http://hdl.handle.net/10985/21215 On the mechanical properties and damage mechanisms of short fibers reinforced composite submitted to hydrothermal aging: Application to sheet molding compound composite TAMBOURA, Sahbi; ABDESSALEM, Abir; BEN DALY, Hachmi; TCHARKHTCHI, Abbas; FITOUSSI, Joseph Sheet Molding compound (SMC) composites were subjected to water immersion tests in order to study their durability since such composites are of interest in automotive applications. Water sorption tests were conducted by immersing specimens in distilled water at 25-90°C for different time durations. In order to investigate the combined action of water and temperature over time on composite mechanical behavior, tensile tests and quasi-static loading were conducted. The mechanical properties of water immersed specimens were evaluated and compared alongside to dry composite behaviour. The tensile tests and quasi-static properties of the studied composite were found to decrease with the increase in moisture uptake. This decrease was attributed toinner structure dégradations by means of osmosis phenomenon. It was shown that hydrothermal aging affects mainly the fiber/matrix interfacial zone while a good adhesion between the reinforcement and the matrix was observed for the virgin samples. In order to well understand the damage mechanisms, scanning electron microspy (in-situ three point bending) tests were performed on aged and non aged specimens. Damage mechanisms were identified for different material states. Results display clearly that damage evolution always begins at the interface regions. Furthermore, a quantitave analysis was performed at a local scale in a representative zone of the tensile area. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/21215 2021-01-01T00:00:00Z TAMBOURA, Sahbi ABDESSALEM, Abir BEN DALY, Hachmi TCHARKHTCHI, Abbas FITOUSSI, Joseph Sheet Molding compound (SMC) composites were subjected to water immersion tests in order to study their durability since such composites are of interest in automotive applications. Water sorption tests were conducted by immersing specimens in distilled water at 25-90°C for different time durations. In order to investigate the combined action of water and temperature over time on composite mechanical behavior, tensile tests and quasi-static loading were conducted. The mechanical properties of water immersed specimens were evaluated and compared alongside to dry composite behaviour. The tensile tests and quasi-static properties of the studied composite were found to decrease with the increase in moisture uptake. This decrease was attributed toinner structure dégradations by means of osmosis phenomenon. It was shown that hydrothermal aging affects mainly the fiber/matrix interfacial zone while a good adhesion between the reinforcement and the matrix was observed for the virgin samples. In order to well understand the damage mechanisms, scanning electron microspy (in-situ three point bending) tests were performed on aged and non aged specimens. Damage mechanisms were identified for different material states. Results display clearly that damage evolution always begins at the interface regions. Furthermore, a quantitave analysis was performed at a local scale in a representative zone of the tensile area.