The Experts below are selected from a list of 22254 Experts worldwide ranked by ideXlab platform
Shaker A. Meguid - One of the best experts on this subject based on the ideXlab platform.
-
Multiscale Modeling of Nanoreinforced Composites
Advances in Nanocomposites, 2016Co-Authors: A.r. Alian, Shaker A. MeguidAbstract:In this chapter, we present different Multiscale Modeling techniques to determine the elastic and interfacial properties of carbon nanotube (CNT)-reinforced polymer composites. The elastic properties of CNT-reinforced composite (hereinafter the “nanocomposite”) are obtained in a two-step approach. First, at the nanoscale level, molecular dynamics (MD) and atomistic-based continuum (ABC) techniques are used to determine the effective elastic properties of a representative volume element (RVE) that is comprised of a nanofiller and its immediate surrounding. Second, at the microscale level, several micromechanics models and hybrid Monte Carlo finite-element (FE) simulations are used to determine the bulk properties of nanocomposite. The interfacial properties are determined through pullout test using MD and ABC techniques. The effect of length, diameter, agglomeration, waviness, defects, and orientation of CNTs on the elastic and interfacial properties of nanocomposites is also investigated. The development of Multiscale Modeling and the proper selection of simulation parameters are discussed in detail. The results of several studies are presented and compared to show the inherited limitations in each technique.
-
Multiscale Modeling of carbon nanotube epoxy composites
Polymer, 2015Co-Authors: A.r. Alian, S I Kundalwal, Shaker A. MeguidAbstract:Abstract In this article, a Multiscale Modeling technique is developed to determine the effective elastic moduli of CNT-reinforced epoxy composites containing either well-dispersed or agglomerated carbon nanotubes (CNTs). Two aspects of the work are accordingly examined. In the first, molecular dynamics simulations are carried out to determine the atomic-level elastic properties of a representative volume element (RVE) comprised of either epoxy polymer or transversely isotropic CNT-epoxy composite. To study the effect of agglomeration of CNTs on the bulk elastic properties of the nanocomposite, CNT bundles of different sizes were considered. A constant-strain energy minimization method is used to determine the elastic coefficients of the RVEs. In the second, the Mori-Tanaka method is used to scale up the properties of the atomic structure to the microscale level, and the outcome is used to investigate the effect of orientations and agglomeration of CNTs on the bulk elastic properties of the nanocomposite. Our results reveal that as the number of CNTs in the bundle increases, the effective elastic properties of the nanocomposite decrease at the same CNT volume fraction.
-
Multiscale Modeling of Nano-Reinforced Structural Adhesive Bonds
2014Co-Authors: J. M. Wernik, Shaker A. MeguidAbstract:In this work, the mechanical properties of carbon nanotube reinforced structural adhesive bonds are investigated both theoretically and experimentally. The theoretical investigations employ a novel Multiscale Modeling technique that integrates governing atomistic constitutive laws in a continuum framework. This technique takes into account the discrete nature of the atomic interactions at the nanometer length scale and the interfacial characteristics of the nanotube and the surrounding polymer matrix. Appropriate formulations are developed to allow for the atomistic-based continuum modelling of nano-reinforced structural adhesive bonds on the basis of a nanoscale representative volume element that accounts for the nonlinear behaviour of its constituents; namely, the reinforcing carbon nanotube, the surrounding adhesive and their interface. This model is used to evaluate the constitutive response of carbon nanotubes with varied chiral indices. The newly developed representative volume element is then used with analytical micromechanical Modeling techniques to investigate the homogeneous and dispersion of the reinforcing element into the adhesive considered upon the linear elastic properties. Copyright © 2013 by ASME.
-
Multiscale Modeling of the nonlinear response of nano-reinforced polymers
Acta Mechanica, 2011Co-Authors: J. M. Wernik, Shaker A. MeguidAbstract:The present study uses a nonlinear representative volume element (RVE) to investigate the effective mechanical properties of a nano-reinforced polymer system. Here, the RVE represents the reinforcing carbon nanotube (CNT), the surrounding polymer matrix, and the CNT–polymer interface. Due to the inherent nanoscale involved in simulating CNT structures, an atomistic description is incorporated via the atomistic-based continuum Multiscale Modeling technique. In this way, the continuum constitutive relations are derived solely from atomistic formulations. The nonlinear response of armchair and zigzag nanotubes and their nano-reinforced polymer equivalents are considered and presented. The results reveal that reinforcing polymeric matrices with 1 to 10 vol% CNTs can result in upward of approximately 23- and 8-fold increases in the tensile and shear stiffness, respectively. These results have a direct bearing on the design and development of nano-reinforced composites.
-
Multiscale Modeling of the nonlinear response of nano-reinforced polymers
Acta Mechanica, 2011Co-Authors: J. M. Wernik, Shaker A. MeguidAbstract:The present study uses a nonlinear representative volume element (RVE) to investigate the effective mechanical properties of a nano-reinforced polymer system. Here, the RVE represents the reinforcing carbon nanotube (CNT), the surrounding polymer matrix, and the CNT-polymer interface. Due to the inherent nanoscale involved in simulating CNT structures, an atomistic description is incorporated via the atomistic-based continuum Multiscale Modeling technique. In this way, the continuum constitutive relations are derived solely from atomistic formulations. The nonlinear response of armchair and zigzag nanotubes and their nano-reinforced polymer equivalents are considered and presented. The results reveal that reinforcing polymeric matrices with 1 to 10 vol% CNTs can result in upward of approximately 23- and 8-fold increases in the tensile and shear stiffness, respectively. These results have a direct bearing on the design and development of nano-reinforced composites. © 2010 Springer-Verlag.
Gregory M. Odegard - One of the best experts on this subject based on the ideXlab platform.
-
6.2 Computational Multiscale Modeling – Nanoscale to Macroscale
Comprehensive Composite Materials II, 2020Co-Authors: Gregory M. OdegardAbstract:Computational Multiscale Modeling can greatly facilitate the development of novel composite materials for a wide range of engineering applications. The primary challenge with this approach is the combined use of a wide range of computational tools that span many orders of length and time scales. This chapter summarizes the various tools that are available to predict material structure/behavior from the atomic level to the bulk structural scale. Also summarized are strategies for linking the various Modeling approaches, constructing appropriate representative volume elements, applying boundary conditions, and establishing an equivalent continuum model. Finally, a Multiscale Modeling case study is detailed that demonstrates how to employ many of the approaches discussed in this chapter.
-
Multiscale Modeling of PEEK using reactive molecular dynamics Modeling and micromechanics
Polymer, 2019Co-Authors: William A. Pisani, Matthew S. Radue, Sorayot Chinkanjanarot, Evan J. Pineda, Brett A. Bednarcyk, Julia A. King, Kevin Waters, Ravindra Pandey, Gregory M. OdegardAbstract:Abstract Polyether ether ketone (PEEK) is a high-performance, semi-crystalline thermoplastic that is used in a wide range of engineering applications, including some structural components of aircraft. The design of new PEEK-based composite materials can be greatly facilitated with a precise understanding of the Multiscale structure and behavior of semi-crystalline PEEK. Molecular Dynamics (MD) Modeling can efficiently predict the response of single-phase polymers at the nanometer length scale, and micromechanics can be used to predict the bulk-level properties of multi-phase materials based on the microstructure. In this study, MD Modeling was used to predict the mechanical response of the amorphous and crystalline phases of PEEK. Employing the MD simulation results as input, the hierarchical microstructure of PEEK, which combines these two phases, was modeled using NASA's micromechanics MSGMC (Multi-Scale Generalized Method of Cells) code. The predicted bulk mechanical properties of semi-crystalline PEEK agree well with the scientific literature data, thus validating the Multiscale Modeling approach. Thus, the proposed Multiscale Modeling method can be used to accurately and efficiently predict the mechanical response of other micro-structurally complex polymer systems.
-
Multiscale Modeling of PEEK Using Reactive Molecular Dynamics and Micromechanics
American Society for Composites 2017, 2017Co-Authors: William A. Pisani, Matthew S. Radue, Sorayot Chinkanjanarot, Evan J. Pineda, Brett A. Bednarcyk, Julia A. King, Gregory M. OdegardAbstract:Polyether ether ketone (PEEK) is a high-performance, semi-crystalline thermoplastic that is used in a wide range of engineering applications, including some structural components of aircraft. The design of new PEEK-based materials requires a precise understanding of the Multiscale structure and behavior of semi-crystalline PEEK. Molecular Dynamics (MD) Modeling can efficiently predict bulk-level properties of single phase polymers, and micromechanics can be used to homogenize those phases based on the overall polymer microstructure. In this study, MD Modeling was used to predict the mechanical properties of the amorphous and crystalline phases of PEEK. The hierarchical microstructure of PEEK, which combines the aforementioned phases, was modeled using a Multiscale Modeling approach facilitated by NASA’s MSGMC. The bulk mechanical properties of semicrystalline PEEK predicted using MD Modeling and MSGMC agree well with vendor data, thus validating the Multiscale Modeling approach.
-
mechanical properties of graphene nanoplatelet carbon fiber epoxy hybrid composites Multiscale Modeling and experiments
Carbon, 2015Co-Authors: Cameron M Hadden, Evan J. Pineda, Julia A. King, Danielle Rene Klimekmcdonald, Alex M Reichanadter, Ibrahim Miskioglu, S Gowtham, Gregory M. OdegardAbstract:Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using Multiscale Modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical Multiscale Modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical Modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the Multiscale Modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite while the effect on the axial properties is shown to be insignificant.
-
Multiscale Modeling of Nanocomposite Materials
Virtual Testing and Predictive Modeling, 2009Co-Authors: Gregory M. OdegardAbstract:Composite and nanocomposite materials have the potential to provide significant increases in specific stiffness and specific strength relative to materials used for many engineering structural applications. To facilitate the design and development of nanocomposite materials, structure–property relationships must be established that predict the bulk mechanical response of these materials as a function of the molecular- and micro-structure. Although many Multiscale Modeling techniques have been developed to predict the mechanical properties of composite materials based on the molecular structure, all of these techniques are limited in terms of their treatment of amorphous molecular structures, time-dependent deformations, molecular behavior detail, and applicability to large deformations. The proper incorporation of these issues into a Multiscale framework may provide efficient and accurate tools for establishing structure–property relationships of composite materials made of combinations of polymers, metals, and ceramics. The objective of this chapter is to describe a general framework for Multiscale Modeling of composite materials. First, the fundamental aspects of efficient and accurate Modeling techniques will be discussed. This will be followed by a review of current state-of-the-art Modeling approaches. Finally, a specific example will be presented that describes the application of the approach to a specific nanocomposite material system.
G Q Lu - One of the best experts on this subject based on the ideXlab platform.
-
Multiscale Modeling and simulation of polymer nanocomposites
Progress in Polymer Science, 2008Co-Authors: Q.h. Zeng, A. B. Yu, G Q LuAbstract:Polymer nanocomposites offer a wide range of promising applications because of their much enhanced properties arising from the reinforcement of nanoparticles. However, further development of such nanomaterials depends on the fundamental understanding of their hierarchical structures and behaviors which requires Multiscale Modeling and simulation strategies to provide seamless coupling among various length and time scales. In this review, we first introduce some computational methods that have been applied to polymer nanocomposites, covering from molecular scale (e.g., molecular dynamics, Monte Carlo), microscale (e.g., Brownian dynamics, dissipative particle dynamics, lattice Boltzmann, time-dependent Ginzburg–Landau method, dynamic density functional theory method) to mesoscale and macroscale (e.g., micromechanics, equivalent-continuum and self-similar approaches, finite element method). Then, we discuss in some detail their applications to various aspects of polymer nanocomposites, including the thermodynamics and kinetics of formation, molecular structure and dynamics, morphology, processing behaviors, and mechanical properties. Finally, we address the importance of Multiscale simulation strategies in the understanding and predictive capabilities of polymer nanocomposites in which few studies have been reported. The present review aims to summarize the recent advances in the fundamental understanding of polymer nanocomposites reinforced by nanofillers (e.g., spherical nanoparticles, nanotubes, clay platelets) and stimulate further research in this area.
Julia A. King - One of the best experts on this subject based on the ideXlab platform.
-
Multiscale Modeling of PEEK using reactive molecular dynamics Modeling and micromechanics
Polymer, 2019Co-Authors: William A. Pisani, Matthew S. Radue, Sorayot Chinkanjanarot, Evan J. Pineda, Brett A. Bednarcyk, Julia A. King, Kevin Waters, Ravindra Pandey, Gregory M. OdegardAbstract:Abstract Polyether ether ketone (PEEK) is a high-performance, semi-crystalline thermoplastic that is used in a wide range of engineering applications, including some structural components of aircraft. The design of new PEEK-based composite materials can be greatly facilitated with a precise understanding of the Multiscale structure and behavior of semi-crystalline PEEK. Molecular Dynamics (MD) Modeling can efficiently predict the response of single-phase polymers at the nanometer length scale, and micromechanics can be used to predict the bulk-level properties of multi-phase materials based on the microstructure. In this study, MD Modeling was used to predict the mechanical response of the amorphous and crystalline phases of PEEK. Employing the MD simulation results as input, the hierarchical microstructure of PEEK, which combines these two phases, was modeled using NASA's micromechanics MSGMC (Multi-Scale Generalized Method of Cells) code. The predicted bulk mechanical properties of semi-crystalline PEEK agree well with the scientific literature data, thus validating the Multiscale Modeling approach. Thus, the proposed Multiscale Modeling method can be used to accurately and efficiently predict the mechanical response of other micro-structurally complex polymer systems.
-
Multiscale Modeling of PEEK Using Reactive Molecular Dynamics and Micromechanics
American Society for Composites 2017, 2017Co-Authors: William A. Pisani, Matthew S. Radue, Sorayot Chinkanjanarot, Evan J. Pineda, Brett A. Bednarcyk, Julia A. King, Gregory M. OdegardAbstract:Polyether ether ketone (PEEK) is a high-performance, semi-crystalline thermoplastic that is used in a wide range of engineering applications, including some structural components of aircraft. The design of new PEEK-based materials requires a precise understanding of the Multiscale structure and behavior of semi-crystalline PEEK. Molecular Dynamics (MD) Modeling can efficiently predict bulk-level properties of single phase polymers, and micromechanics can be used to homogenize those phases based on the overall polymer microstructure. In this study, MD Modeling was used to predict the mechanical properties of the amorphous and crystalline phases of PEEK. The hierarchical microstructure of PEEK, which combines the aforementioned phases, was modeled using a Multiscale Modeling approach facilitated by NASA’s MSGMC. The bulk mechanical properties of semicrystalline PEEK predicted using MD Modeling and MSGMC agree well with vendor data, thus validating the Multiscale Modeling approach.
-
mechanical properties of graphene nanoplatelet carbon fiber epoxy hybrid composites Multiscale Modeling and experiments
Carbon, 2015Co-Authors: Cameron M Hadden, Evan J. Pineda, Julia A. King, Danielle Rene Klimekmcdonald, Alex M Reichanadter, Ibrahim Miskioglu, S Gowtham, Gregory M. OdegardAbstract:Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using Multiscale Modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical Multiscale Modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical Modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the Multiscale Modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite while the effect on the axial properties is shown to be insignificant.
Evan J. Pineda - One of the best experts on this subject based on the ideXlab platform.
-
Multiscale Modeling of PEEK using reactive molecular dynamics Modeling and micromechanics
Polymer, 2019Co-Authors: William A. Pisani, Matthew S. Radue, Sorayot Chinkanjanarot, Evan J. Pineda, Brett A. Bednarcyk, Julia A. King, Kevin Waters, Ravindra Pandey, Gregory M. OdegardAbstract:Abstract Polyether ether ketone (PEEK) is a high-performance, semi-crystalline thermoplastic that is used in a wide range of engineering applications, including some structural components of aircraft. The design of new PEEK-based composite materials can be greatly facilitated with a precise understanding of the Multiscale structure and behavior of semi-crystalline PEEK. Molecular Dynamics (MD) Modeling can efficiently predict the response of single-phase polymers at the nanometer length scale, and micromechanics can be used to predict the bulk-level properties of multi-phase materials based on the microstructure. In this study, MD Modeling was used to predict the mechanical response of the amorphous and crystalline phases of PEEK. Employing the MD simulation results as input, the hierarchical microstructure of PEEK, which combines these two phases, was modeled using NASA's micromechanics MSGMC (Multi-Scale Generalized Method of Cells) code. The predicted bulk mechanical properties of semi-crystalline PEEK agree well with the scientific literature data, thus validating the Multiscale Modeling approach. Thus, the proposed Multiscale Modeling method can be used to accurately and efficiently predict the mechanical response of other micro-structurally complex polymer systems.
-
Multiscale Modeling of PEEK Using Reactive Molecular Dynamics and Micromechanics
American Society for Composites 2017, 2017Co-Authors: William A. Pisani, Matthew S. Radue, Sorayot Chinkanjanarot, Evan J. Pineda, Brett A. Bednarcyk, Julia A. King, Gregory M. OdegardAbstract:Polyether ether ketone (PEEK) is a high-performance, semi-crystalline thermoplastic that is used in a wide range of engineering applications, including some structural components of aircraft. The design of new PEEK-based materials requires a precise understanding of the Multiscale structure and behavior of semi-crystalline PEEK. Molecular Dynamics (MD) Modeling can efficiently predict bulk-level properties of single phase polymers, and micromechanics can be used to homogenize those phases based on the overall polymer microstructure. In this study, MD Modeling was used to predict the mechanical properties of the amorphous and crystalline phases of PEEK. The hierarchical microstructure of PEEK, which combines the aforementioned phases, was modeled using a Multiscale Modeling approach facilitated by NASA’s MSGMC. The bulk mechanical properties of semicrystalline PEEK predicted using MD Modeling and MSGMC agree well with vendor data, thus validating the Multiscale Modeling approach.
-
mechanical properties of graphene nanoplatelet carbon fiber epoxy hybrid composites Multiscale Modeling and experiments
Carbon, 2015Co-Authors: Cameron M Hadden, Evan J. Pineda, Julia A. King, Danielle Rene Klimekmcdonald, Alex M Reichanadter, Ibrahim Miskioglu, S Gowtham, Gregory M. OdegardAbstract:Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using Multiscale Modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical Multiscale Modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical Modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the Multiscale Modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite while the effect on the axial properties is shown to be insignificant.
