Interface mechanics of carbon fibers with radially-grown carbon nanotubes

Subramanian, Nithya; Koo, Bonsung; Venkatesan, Karthik Rajan; Chattopadhyay, Aditi

doi:10.1016/j.carbon.2018.03.090

Cited by 23 publications

(12 citation statements)

References 30 publications

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“…Experimental investigations at material interfaces are challenging due to the limitations in direct measurement techniques, test specimen size and preparation, and uncertainty in the data from indirect measurements. Computational methods using atomistic simulations have been used in literature to understand the physical and chemical parameters that affect the mechanical response of interphases in multiphase materials [19][20][21].…”

Section: Molecular Modellingmentioning

confidence: 99%

Multiscale Damage in Co-Cured Composites—perspectives From Experiments and Modelling

Subramanian¹,

Bisagni²

2021

American Society for Composites 2021

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Bonded and co-cured composites are popular alternatives to structures joined with mechanical fasteners in aircraft but the complex and coupled damage mechanisms in the co-cured/bonded region are poorly understood, thus making the evaluation of their strength and durability difficult with current modelling strategies. This study explores the potential of interleaf inclusion in failure-prone, critical regions of co-cured composite specimens in improving the joint strength and interface fracture toughness and strives to advance the understanding of damage initiation in the co-cured region using an atomistic model. A two-pronged approach is pursued here with bench-scale experimental testing and molecular modelling in this study. Experiments are performed for mode I fracture toughness with double cantilever beam (DCB) on composite laminates with an epoxy interleaf layer. Two epoxy resins and three methods for interleaf inclusion are explored in this study; we supplement the results from DCB testing with insights from confocal microscopy on the crack tip and the interleaf layer pre- and post-testing. Molecular dynamic (MD) simulations capture the cohesive interactions at the threephase interface containing the carbon fiber, the prepreg epoxy, and the interleaf epoxy. Results highlight that an interleaf layer made from partially-cured and filmed epoxy, further consolidated in the composite lay-up is the most effective way to suppress void formation, improve dispersion, and maximize cohesive interactions at the interface of co-cured composites.

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Section: Molecular Modellingmentioning

confidence: 99%

Multiscale Damage in Co-Cured Composites—perspectives From Experiments and Modelling

Subramanian¹,

Bisagni²

2021

American Society for Composites 2021

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“…15,16 The graphene sheet is adopted as the model of the carbon fiber surface to characterize the fiber/matrix adhesion properties in different CFRP composites. 17−19 Hybrid CFRP composites incorporating CNT 20,21 and graphene nanoplatelets 22 have also been investigated by MD simulations. The interfacial properties of the hybrid CFRP composite containing ZnO NWs were compared with the bare structure in our previous MD simulation study, showing up to 120% improvement in the interfacial strength.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the MD simulation analysis, different parameters, such as the loading temperature and loading rate, can affect the traction–separation behavior of the graphene-based polymer composites . The mechanical and thermal properties of the graphene-reinforced cross-linked epoxy have also been investigated by MD simulations. , The graphene sheet is adopted as the model of the carbon fiber surface to characterize the fiber/matrix adhesion properties in different CFRP composites. − Hybrid CFRP composites incorporating CNT , and graphene nanoplatelets have also been investigated by MD simulations. The interfacial properties of the hybrid CFRP composite containing ZnO NWs were compared with the bare structure in our previous MD simulation study, showing up to 120% improvement in the interfacial strength .…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations on Structural Characteristics of ZnO Nanowire-Enhanced Graphene/Epoxy Polymer Composites: Implications for Lightweight Structures

Marashizadeh

Abshirini

Saha

et al. 2021

ACS Appl. Nano Mater.

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Improving the interfacial properties between fiber and polymer is critical for developing high-performance, lightweight composite materials. One approach is growing nanomaterials on the fiber surface as the secondary reinforcement to enhance the fiber/matrix bonding. Atomistic investigations of the interfacial properties of the ZnO nanowire (NW)-enhanced carbon fiber polymer composite are presented in this study. Molecular dynamics (MD) simulation is conducted to evaluate the effect of the ZnO NW diameter, ZnO NW length, ZnO NW/graphene crystal twisting angle, loading temperature, and separation rate on the traction−separation behavior of the hybrid structure. A representative volume element is developed at the atomic scale, containing a ZnO NW aligned on the fiber surface and embedded in the cross-linked epoxy polymer. The cohesive parameters, such as penalty stiffness, interfacial strength, and cohesive energy, are extracted from the separation of the graphene sheet from the ZnO NW/epoxy in the opening mode (normal separation). Improved adhesion properties in ZnO NW-enhanced composites are observed by comparing the results of the hybrid structures with the bare one (no ZnO NW). Higher interfacial properties are achieved by reducing the diameter of ZnO NW in the enhanced structures. A negligible effect of changing the ZnO NW length on the interfacial stiffness is observed, while incorporating shorter NWs result in higher interfacial strength and cohesive energy values. Results show that the interface in the hybrid composite is sensitive to the twisting angle of the ZnO's hexagonal-shaped plane with respect to the graphene's crystal. For instance, the interfacial strength of 0°t wisting angle is 25% higher than the 45°angle. The MD results reveal that increasing the loading temperature leads to a weaker interface. Interfacial properties are initially improved by increasing the loading rate and then become rate-independent at separation rates higher than 25 Å/ps.

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“…As for a reliable modelling design tool for hierarchical FRCs with CNTs, the primary requirement is that it is able to describe various mechanisms of energy absorption and their dependence on the morphology of the CNT network in the presence of fibers. The atomistic models [21,22] that only contain a single or few CNTs are incapable of revealing the morphological effects. Modelling many CNTs with realistic dimensions is not feasible with these models due to computational cost.…”

Section: Introductionmentioning

confidence: 99%

Enhancing Strength and Toughness of Hierarchical Composites through Optimization of Position and Orientation of Nanotubes: A Computational Study

2020

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Hierarchical composites that combine microscopic fibers and carbon nanotubes (CNTs) offer opportunities to further improve mechanical properties. Motivated by the experimental evidence that the spatial distribution of CNTs has a significant effect on the strength and toughness of these composites, we developed a novel modelling tool to help us explore mechanisms of strengthening and toughening in an efficient way. The spatial position and orientation of CNTs are chosen as design variables and their optimization is performed on the example of a unidirectional fiber-reinforced composite (FRC) subjected to transverse tensile loading. The model relies on the use of genetic algorithm and finite element method. Our modelling results show that the CNT network with an optimized morphology suppresses stress concentrations in the matrix near the fibers. The optimized morphology is shown to activate a new strengthening and toughening mechanism—diffusion of damage at micro-scale. It allows substantial increase in the consumption of the strain energy by matrix cracking, delocalization of damage, and with it, improvement of the strength and toughness. When the network morphology of 1.0 wt% of CNTs is optimized, the strength and toughness are increased by 49% and 65%, respectively, compared to the pristine FRC. The same amount of homogenously distributed CNTs in the composite leads to only 2% of the strength increase accompanied by a 13% decrease in toughness. The work emphasizes the importance of optimizing spatial position and orientation of CNTs for the strength and toughness improvements of composites.

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Interface mechanics of carbon fibers with radially-grown carbon nanotubes

Cited by 23 publications

References 30 publications

Multiscale Damage in Co-Cured Composites—perspectives From Experiments and Modelling

Multiscale Damage in Co-Cured Composites—perspectives From Experiments and Modelling

Atomistic Simulations on Structural Characteristics of ZnO Nanowire-Enhanced Graphene/Epoxy Polymer Composites: Implications for Lightweight Structures

Enhancing Strength and Toughness of Hierarchical Composites through Optimization of Position and Orientation of Nanotubes: A Computational Study

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