The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

H. Ben Dali - One of the best experts on this subject based on the ideXlab platform.

  • Two Hybrid Approaches to Fatigue Modeling of Advanced-Sheet Molding Compounds (A-SMC) Composite
    Applied Composite Materials, 2020
    Co-Authors: H. Ayari, Mohammadali Shirinbayan, J. Fitoussi, A. Imaddahen, S. Tamboura, H. Ben Dali, Abbas Tcharkhtchi
    Abstract:

    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.

  • Microstructure dependent fatigue life prediction for short fibers reinforced composites: Application to Sheet Molding Compounds
    International Journal of Fatigue, 2020
    Co-Authors: M.a. Laribi, Mohammadali Shirinbayan, Joseph Fitoussi, Abbas Tcharkhtchi, Sahbi Tamboura, H. Ben Dali
    Abstract:

    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.

Abbas Tcharkhtchi - One of the best experts on this subject based on the ideXlab platform.

  • Two Hybrid Approaches to Fatigue Modeling of Advanced-Sheet Molding Compounds (A-SMC) Composite
    Applied Composite Materials, 2020
    Co-Authors: H. Ayari, Mohammadali Shirinbayan, J. Fitoussi, A. Imaddahen, S. Tamboura, H. Ben Dali, Abbas Tcharkhtchi
    Abstract:

    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.

  • Microstructure dependent fatigue life prediction for short fibers reinforced composites: Application to Sheet Molding Compounds
    International Journal of Fatigue, 2020
    Co-Authors: M.a. Laribi, Mohammadali Shirinbayan, Joseph Fitoussi, Abbas Tcharkhtchi, Sahbi Tamboura, H. Ben Dali
    Abstract:

    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.

  • Effect of a Post-Fatigue Damage on the Residual Dynamic Behavior of Advanced-SMC Composites
    Applied Composite Materials, 2019
    Co-Authors: Mohammadali Shirinbayan, B. Surowiec, Sadegh Farzaneh, Fodil Meraghni, Joseph Fitoussi, Abbas Tcharkhtchi
    Abstract:

    The purpose of this article is to investigate the effect of an initial pre-damage induced by a fatigue loading on the tensile dynamic behavior of Advanced Sheet Molding Compounds (A-SMC). Tension-tension fatigue preloading at a frequency of 30 Hz is performed at various applied stress levels prior to subject the A-SMC specimens to tensile tests at different strain rates, namely: 10^−3 s^−1 (quasi-static), 1 s^−1 and 60 s^−1. The developed experimental approach provided significant findings in terms of residual behavior and damage accumulation in relation to the applied pre-fatigue loading conditions. Indeed, it has been shown that the overall quasi-static and the dynamic responses are strongly affected by the level of fatigue number of cycles reached prior to applying the high strain loading. The effect of fatigue pre-damage is found also strongly strain-rate dependent. Experimental results showed that the damage threshold in terms of stress and strain increased with strain rate. However, for a given strain-rate the damage stress threshold depends on the number of cycles applied during the fatigue preloading.

  • Multi-Scale Damage and Mechanical Behavior of Sheet Molding Compound Composites Subjected to Fatigue, Dynamic, and Post-Fatigue Dynamic Loadings
    2019
    Co-Authors: Mohammadali Shirinbayan, J. Fitoussi, N. Abbasnezhad, A. Lucas, Abbas Tcharkhtchi
    Abstract:

    Sheet Molding Compounds (SMCs) with special microstructures are very attractive to use in automobile structures especially when they are accidentally subjected to collision type accidents because of their high energy absorption capacity. These are materials designated as standard SMC, Advanced Sheet Molding Compounds (A-SMC), Low-Density SMC (LD-SMC) and etc. In this study, testing methods have been performed to compare the mechanical responses and damage phenomena of SMC, LD-SMC, and A-SMC under quasi-static and high strain rate tensile tests. The paper also aims at investigating the effect of an initial pre-damage induced by fatigue on the tensile dynamic behavior of A-SMC. In the case of SMCs and A-SMCs, whatever the fibers orientation and applied strain rate are, the first observed phenomenon of damage corresponds to decohesion of the fiber-matrix interface which is followed by coalescence and multiplication of these micro-cracks and their propagations. For LD-SMCs, damage mechanisms depend on the presence of Hollow Glass Microspheres (HGM) and fibers orientation

Kyriaki Kalaitzidou - One of the best experts on this subject based on the ideXlab platform.

  • composites made from cf prepreg trim waste tapes using Sheet Molding Compounds smc technology challenges and potential
    Composites Part A-applied Science and Manufacturing, 2020
    Co-Authors: Sanzida Sultana, Amir Asadi, Jonathan S Colton, Kyriaki Kalaitzidou
    Abstract:

    Abstract This study explores the use of carbon fiber (CF) prepreg trim waste to manufacture lightweight, high performance and low cost CF composites using Sheet Molding compound (SMC) technology. First, the modifications of a typical SMC and a flow study to determine the charge in size and mass of the Sheets are determined. Then, the effect of the age of the prepreg tapes, aspect ratio of cut chips and pressure during compression Molding on the tensile and impact properties of the composites is determined and these properties are compares with those of typical SMC composites. It is concluded that (i) the standard SMC production line needs to be modified in order to successfully convert CF tapes into Sheets and (ii) the produced CF composites can meet the high stiffness and acceptable strength for not strength-critical applications without the need to store the prepreg trim waste in controlled conditions.

  • basalt fibers as a sustainable and cost effective alternative to glass fibers in Sheet Molding compound smc
    Composites Part B-engineering, 2017
    Co-Authors: Amir Asadi, Ferdinand Baaij, Hendrik Mainka, Michael Rademacher, Jeffrey Thompson, Kyriaki Kalaitzidou
    Abstract:

    Abstract The focus of this study is to explore the feasibility of using basalt fibers (BF) as a potential sustainable alternative to glass fibers (GF) in Sheet Molding Compounds (SMC) to reduce the weight and cost of conventional GF SMC. The interfacial interactions for BF/epoxy and GF/epoxy composites were assessed through single fiber fragmentation tests. The mechanical properties, including tensile and flexural modulus and strength, impact strength and thermomechanical properties for 25 wt% BF/epoxy composites made using SMC were determined and directly compared to 25 wt% GF/epoxy SMC composites. As indicated by the single fiber fragmentation tests, the two composites had similar interfacial shear strength (IFSS) and consequently similar adhesion at the fiber-epoxy interface. In addition, no distinguishable differences were found in the curing behavior of the two SMC composites. The storage modulus of the 25 wt% BF/epoxy composites was found to be higher than that of 25GF/epoxy in the glassy state. Moreover, the average tensile and flexural properties (both absolute and specific values) of the 25 wt% BF/epoxy SMC composites were higher or at least equal to those of 25 wt% GF/epoxy SMC composites. No difference in the impact strength of the two composites was recorded considering the statistical variation. In general, BF/epoxy SMC composites showed better or equal mechanical performance compared to GF/epoxy SMC composites suggesting that BF may be an alternative to GF with the potential to lead to lower cost SMC composites.

  • Introducing cellulose nanocrystals in Sheet Molding Compounds (SMC)
    Composites Part A-applied Science and Manufacturing, 2016
    Co-Authors: Amir Asadi, Mark Miller, Sanzida Sultana, Robert J. Moon, Kyriaki Kalaitzidou
    Abstract:

    Abstract The mechanical properties of short glass fiber/epoxy composites containing cellulose nanocrystals (CNC) made using Sheet Molding compound (SMC) manufacturing method as well as the rheological and thermomechanical properties of the CNC-epoxy composites were investigated as a function of the CNC content. CNC up to 1.4 wt% were dispersed in the epoxy to produce the resin for SMC production. The addition of CNC in the resin increased its viscosity and slightly reduced the heat of reaction during the polymerization without altering the curing time and temperature and the effective pot life of the resin. The incorporation of 0.9 wt% CNC in the SMC composite resulted in increases in elastic modulus and tensile strength by ∼25% and ∼30% and in flexural modulus and strength by ∼44% and ∼33% respectively. Concentrations of CNC up to 0.9 wt% in the SMC composite did not alter the impact energy.

Mohammadali Shirinbayan - One of the best experts on this subject based on the ideXlab platform.

  • Two Hybrid Approaches to Fatigue Modeling of Advanced-Sheet Molding Compounds (A-SMC) Composite
    Applied Composite Materials, 2020
    Co-Authors: H. Ayari, Mohammadali Shirinbayan, J. Fitoussi, A. Imaddahen, S. Tamboura, H. Ben Dali, Abbas Tcharkhtchi
    Abstract:

    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.

  • Microstructure dependent fatigue life prediction for short fibers reinforced composites: Application to Sheet Molding Compounds
    International Journal of Fatigue, 2020
    Co-Authors: M.a. Laribi, Mohammadali Shirinbayan, Joseph Fitoussi, Abbas Tcharkhtchi, Sahbi Tamboura, H. Ben Dali
    Abstract:

    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.

  • Effect of a Post-Fatigue Damage on the Residual Dynamic Behavior of Advanced-SMC Composites
    Applied Composite Materials, 2019
    Co-Authors: Mohammadali Shirinbayan, B. Surowiec, Sadegh Farzaneh, Fodil Meraghni, Joseph Fitoussi, Abbas Tcharkhtchi
    Abstract:

    The purpose of this article is to investigate the effect of an initial pre-damage induced by a fatigue loading on the tensile dynamic behavior of Advanced Sheet Molding Compounds (A-SMC). Tension-tension fatigue preloading at a frequency of 30 Hz is performed at various applied stress levels prior to subject the A-SMC specimens to tensile tests at different strain rates, namely: 10^−3 s^−1 (quasi-static), 1 s^−1 and 60 s^−1. The developed experimental approach provided significant findings in terms of residual behavior and damage accumulation in relation to the applied pre-fatigue loading conditions. Indeed, it has been shown that the overall quasi-static and the dynamic responses are strongly affected by the level of fatigue number of cycles reached prior to applying the high strain loading. The effect of fatigue pre-damage is found also strongly strain-rate dependent. Experimental results showed that the damage threshold in terms of stress and strain increased with strain rate. However, for a given strain-rate the damage stress threshold depends on the number of cycles applied during the fatigue preloading.

  • Multi-Scale Damage and Mechanical Behavior of Sheet Molding Compound Composites Subjected to Fatigue, Dynamic, and Post-Fatigue Dynamic Loadings
    2019
    Co-Authors: Mohammadali Shirinbayan, J. Fitoussi, N. Abbasnezhad, A. Lucas, Abbas Tcharkhtchi
    Abstract:

    Sheet Molding Compounds (SMCs) with special microstructures are very attractive to use in automobile structures especially when they are accidentally subjected to collision type accidents because of their high energy absorption capacity. These are materials designated as standard SMC, Advanced Sheet Molding Compounds (A-SMC), Low-Density SMC (LD-SMC) and etc. In this study, testing methods have been performed to compare the mechanical responses and damage phenomena of SMC, LD-SMC, and A-SMC under quasi-static and high strain rate tensile tests. The paper also aims at investigating the effect of an initial pre-damage induced by fatigue on the tensile dynamic behavior of A-SMC. In the case of SMCs and A-SMCs, whatever the fibers orientation and applied strain rate are, the first observed phenomenon of damage corresponds to decohesion of the fiber-matrix interface which is followed by coalescence and multiplication of these micro-cracks and their propagations. For LD-SMCs, damage mechanisms depend on the presence of Hollow Glass Microspheres (HGM) and fibers orientation

Le Corre Steven - One of the best experts on this subject based on the ideXlab platform.

  • Anisotropic viscous behavior of Sheet Molding Compounds (SMC) during compression Molding
    'Elsevier BV', 2003
    Co-Authors: Dumont, Pierre J.j., Le Corre Steven, Orgéas Laurent, Favier Denis
    Abstract:

    International audienceTo improve the knowledge on the rheology of Sheet Molding Compounds (SMC) during compression Molding, a specific rheometer was designed, allowing to perform homogeneous experiments on SMC specimen under various mechanical loading, strain rates and fiber contents. Results gained during experiments underlined the key role played both by the strain rate and the fiber content. A viscous and transversely isotropic model was then proposed and used to fit stress levels recorded during the experiments. This model that requires few constitutive parameters rather well describes the main features of SMC rheology

  • Etude de la mise en forme par compression des Sheet Molding Compounds (SMC)
    HAL CCSD, 2001
    Co-Authors: Le Corre Steven
    Abstract:

    Etude de la mise en forme par compression des Sheet Molding Compounds (SMC)Study of the compression forming process of Sheet Molding Compounds (SMC

  • Etude de la mise en forme par compression des Sheet Molding Compounds (SMC)
    2001
    Co-Authors: Le Corre Steven, Favier Denis
    Abstract:

    ce document est une contribution à l'étude du procédé de mise en forme des Sheet Molding Compounds (SMC), composites faits d'une matrice polymère thermodurcissable renforcée par des fibres de verre courtes. A terme, l'objectif est de développer un logiciel de simulation permettant de prévoir la distribution et l'orientation des fibres au cours du moulage. Le travail s'articule autour de la construction d'un modèle de comportement biphasique basé sur la théorie des mélanges, nécessaire à la prédiction de la redistribution des fibres. Dans cette approche, le SMC est vu comme la superposition d'un milieu fibres et d'un milieu pâte. La construction du modèle s'appuie sur l'étude expérimentale du comportement des SMC sous sollicitations homogènes. Les dispositifs expérimentaux développés et les essais réalisés permettent de quantifier l'influence de la vitesse de déformation, la température et la teneur en fibres sur la rhéologie du matériau. Ils permettent de mieux comprendre les phénomènes physiques qui ont lieu lors du moulage et fournissent les données nécessaires à la spécification du modèle biphasique. Le milieu pâte est assimilé à un fluide en loi puissance, compressible et isotrope dont le comportement est déduit des expériences. Le comportement du milieu fibres est obtenu par homogénéisation des structures discrètes périodiques, ce qui permet d'identifier un modèle de fluide orthotrope en loi puissance reliant les propriétés microstructurales (taux, orientation et géométrie des fibres) aux propriétés macroscopiques. Une loi d'interaction fibres/pâte est proposée grâce à une étude bibliographique sur l'écoulement d'un fluide en milieu poreux anisotrope. La dernière partie de cet ouvrage est consacrée à l'écriture d'un modèle biphasique simplifié. Les observations expérimentales de l'écoulement en conditions industrielles conduisent à adopter une description simplifiée permettant de se ramener à un modèle coque qui sera implanté dans un code de simulation numérique.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF