The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
P P Camanho - One of the best experts on this subject based on the ideXlab platform.
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prediction of size effects in open hole Laminates using only the young s modulus the strength and the r curve of the 0 ply
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: C Furtado, Brian L. Wardle, A Arteiro, Miguel A Bessa, P P CamanhoAbstract:Advanced non-linear Finite Element models for the strength prediction of composite Laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the Laminate Level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer Laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R-curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general Laminates, and an analytical model to estimate the R-curve of balanced Laminates. These Laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.
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Prediction of size effects in open-hole Laminates using only the Young’s modulus, the strength, and the R-curve of the 0° ply
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: C Furtado, Brian L. Wardle, A Arteiro, Miguel A Bessa, P P CamanhoAbstract:Advanced non-linear Finite Element models for the strength prediction of composite Laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the Laminate Level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer Laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R-curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general Laminates, and an analytical model to estimate the R-curve of balanced Laminates. These Laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.
Brian L. Wardle - One of the best experts on this subject based on the ideXlab platform.
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Nano-engineered Composites Reinforced with Aligned Carbon Nanotubes (CNTs)
2020Co-Authors: Sunny S. Wicks, Namiko Yamamoto, R. Guzman De Villoria, K. Ishiguro, Hulya Cebeci, Brian L. WardleAbstract:We present the implementation of aligned carbon nanotubes (CNTs) as a method to enhance properties of traditional advanced composites. The hybrid composites are 3-dimensional architectures of aligned CNTs, and existing advanced fibers and polymeric resins creating nanoengineered composites. Our work to date has focused on interlaminar strength and toughness, and electrical and thermal conductivities of two Laminate-Level architectures. The first approach utilizes aligned CNT forests placed between ply layers perpendicular to the fiber direction to create “nano-stitches”. The second approach involves growing the CNTs directly on woven alumina fibers, so that the CNTs extend radially outward from every fiber forming “fuzzy fibers”. Three standard processing routes for are reviewed: nano-stitching of graphite/epoxy prepreg, nanostitching of graphite/epoxy cloth in a resin-infusion process, and hand layup of fuzzy fiber ceramic cloth.
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prediction of size effects in open hole Laminates using only the young s modulus the strength and the r curve of the 0 ply
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: C Furtado, Brian L. Wardle, A Arteiro, Miguel A Bessa, P P CamanhoAbstract:Advanced non-linear Finite Element models for the strength prediction of composite Laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the Laminate Level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer Laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R-curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general Laminates, and an analytical model to estimate the R-curve of balanced Laminates. These Laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.
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Prediction of size effects in open-hole Laminates using only the Young’s modulus, the strength, and the R-curve of the 0° ply
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: C Furtado, Brian L. Wardle, A Arteiro, Miguel A Bessa, P P CamanhoAbstract:Advanced non-linear Finite Element models for the strength prediction of composite Laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the Laminate Level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer Laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R-curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general Laminates, and an analytical model to estimate the R-curve of balanced Laminates. These Laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.
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Polymers and advanced polymer-matrix composites reinforced with aligned carbon nanotubes
24th Annual Technical Conference of the American Society for Composites 2009 and 1st Joint Canadian-American Technical Conference on Composites, 2009Co-Authors: Brian L. WardleAbstract:Although bulk nanostructured materials pose many challenges in terms of characterization, design, processing, and scaling, advanced composites can be engineered at the nanoscale to achieve significant macroscopic engineering property enhancement and tailoring. Recent work on integration of aligned carbon nanotubes (CNT) into polymer matrices of existing fiber-reinforced plastic (FRP) systems is reviewed in the context of measured bulk multifunctional properties such as Laminate strength, toughness, and electrical and thermal conductivities. These results motivate study of aligned-CNT polymer nanocomposites (PNCs), which comprise the hybridized microscopic interfiber spaces of the macroscopic 3D-reinforced nanoengineered composites. In addition to comprising the hybrid matrix component in nano-engineered composites, aligned-CNT PNCs (A-PNCs), are interesting new materials themselves with applications in many areas such as thermal interfaces and possibly structural elements at high CNT volume fractions. This paper focuses on mechanics aspects of both A-PNCs and nano-engineered composites, with brief discussion of multifunctional aspects such as thermal and electrical transport. The effect of nano-scale morphology is shown to be the dominant factor in modulus enhancement of PNCs due to the aligned CNT reinforcing 'fibers'. At the macroscopic scale, the effects of 3D aligned-CNT reinforcement in the interlaminar ('nanostitch' architecture) and intralaminar ('fuzzy-fiber' architecture) regions are assessed through models of interlaminar fracture toughness and load-transfer to fibers having in situgrown aligned CNTs. Prior experimental work has demonstrated that aligned CNTs significantly enhance Laminate-Level multifunctional properties of existing aerospacegrade advanced composites, including strength and toughness. Fundamental multiscale and multi-physics studies linking PNC (nano- to micro-scale) attributes to the nano-engineered composite (micro- to macro-scale) performance, such as those presented here based on mechanics, will help improve design of these hybrid advanced composite materials with enhanced performance over existing systems.
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Fabrication and multifunctional properties of a hybrid Laminate with aligned carbon nanotubes grown In Situ
Composites Science and Technology, 2008Co-Authors: Enrique J Garcia, Brian L. Wardle, A. John Hart, Namiko YamamotoAbstract:Abstract A hybrid composite architecture of carbon nanotubes (CNTs), advanced fibers and a matrix is described, from CNT synthesis and characterization through to standard mechanical and electrical Laminate tests. Direct growth of aligned CNTs on the surface of advanced fibers in a woven fabric enables enhancement in multifunctional Laminate performance, as demonstrated by a 69% increase in interlaminar shear strength and 106 (in-plane) and 108 (through-thickness) increases in Laminate-Level electrical conductivity. Processes developed include dip-coating of CNT growth catalyst and atmospheric-pressure chemical vapor deposition of dense aligned CNTs. A capillarity-driven mechanism is presented to explain the observed effective and uniform wetting of the aligned CNTs in the interior of the Laminate by unmodified thermoset polymer resins.
A. Ellison - One of the best experts on this subject based on the ideXlab platform.
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A new multi-layer approach for progressive damage simulation in composite Laminates based on isogeometric analysis and Kirchhoff–Love shells. Part I: basic theory and modeling of delamination and transverse shear
Computational Mechanics, 2018Co-Authors: Y. Bazilevs, M. S. Pigazzini, A. EllisonAbstract:In this two-part paper we introduce a new formulation for modeling progressive damage in Laminated composite structures. We adopt a multi-layer modeling approach, based on Isogeometric Analysis (IGA), where each ply or lamina is represented by a spline surface, and modeled as a Kirchhoff–Love thin shell. Continuum Damage Mechanics is used to model intralaminar damage, and a new zero-thickness cohesive-interface formulation is introduced to model delamination as well as permitting Laminate-Level transverse shear compliance. In Part I of this series we focus on the presentation of the modeling framework, validation of the framework using standard Mode I and Mode II delamination tests, and assessment of its suitability for modeling thick Laminates. In Part II of this series we focus on the application of the proposed framework to modeling and simulation of damage in composite Laminates resulting from impact. The proposed approach has significant accuracy and efficiency advantages over existing methods for modeling impact damage. These stem from the use of IGA-based Kirchhoff–Love shells to represent the individual plies of the composite Laminate, while the compliant cohesive interfaces enable transverse shear deformation of the Laminate. Kirchhoff–Love shells give a faithful representation of the ply deformation behavior, and, unlike solids or traditional shear-deformable shells, do not suffer from transverse-shear locking in the limit of vanishing thickness. This, in combination with higher-order accurate and smooth representation of the shell midsurface displacement field, allows us to adopt relatively coarse in-plane discretizations without sacrificing solution accuracy. Furthermore, the thin-shell formulation employed does not use rotational degrees of freedom, which gives additional efficiency benefits relative to more standard shell formulations.
C Furtado - One of the best experts on this subject based on the ideXlab platform.
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prediction of size effects in open hole Laminates using only the young s modulus the strength and the r curve of the 0 ply
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: C Furtado, Brian L. Wardle, A Arteiro, Miguel A Bessa, P P CamanhoAbstract:Advanced non-linear Finite Element models for the strength prediction of composite Laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the Laminate Level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer Laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R-curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general Laminates, and an analytical model to estimate the R-curve of balanced Laminates. These Laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.
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Prediction of size effects in open-hole Laminates using only the Young’s modulus, the strength, and the R-curve of the 0° ply
Composites Part A-applied Science and Manufacturing, 2017Co-Authors: C Furtado, Brian L. Wardle, A Arteiro, Miguel A Bessa, P P CamanhoAbstract:Advanced non-linear Finite Element models for the strength prediction of composite Laminates normally result in long computing times that are not suitable for preliminary sizing and optimisation of structural details. Macro-mechanical analytical models, in spite of providing quick predictions, are based on properties determined from tests performed at the Laminate Level, making preliminary design and optimisation of composite structures still too costly in terms of testing requirements. To overcome these disadvantages, an analytical framework is proposed to predict the notched response of balanced carbon fibre-reinforced polymer Laminates using only three ply properties as inputs: the longitudinal Young’s modulus, the longitudinal strength, and the R-curve of the 0° plies. This framework is based on invariant-based approaches to predict the stiffness and the strength of general Laminates, and an analytical model to estimate the R-curve of balanced Laminates. These Laminate properties are then used in a Finite Fracture Mechanics model to predict size effects. The predictions for open-hole tension and compression tests are compared with experimental results obtained from the literature for five different material systems. Good agreement is observed considering that only three ply properties are used as inputs for the analytical framework.
N. Upadhyay - One of the best experts on this subject based on the ideXlab platform.
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Failure Analysis of Unidirectional Ceramic Matrix Composite Lamina and Cross-Ply Laminate under Fiber Direction Uniaxial Tensile Load: Cohesive Zone Modeling and Brittle Fracture Mechanics Approach
Journal of Materials Engineering and Performance, 2020Co-Authors: S. Daggumati, A. Sharma, A. Kasera, N. UpadhyayAbstract:The current research work presents the computational micromechanical analysis of the room temperature tensile failure behavior of unidirectional (UD) and cross-ply (0/90) ceramic matrix composites (CMCs). For computational micromechanical analysis, three-dimensional (3D) representative volume element (RVE) and multi-fiber multilayer RVE (M^2 RVE) models are generated that are representative of the lamina and the Laminate under investigation. The RVE and M^2 RVE models are generated by replicating the fiber distribution, and the placement of the fibers observed in a microscopic image of an actual CMC Laminate. The generated RVE models consist of the discrete representation of individual constituent phases of the CMC such as fibers, interphase, matrix, and the fiber–interphase interface region. Under the applied external tensile load, the fiber–interphase interface interactions are modeled using the cohesive elements that follow the bilinear traction separation law. The matrix, fiber, and interphase materials failure behavior is captured using a brittle cracking model. In order to validate the proposed numerical methodology, the predicted average stress–strain curve at the UD Laminate Level is compared to the experimental stress–strain curve reported in the literature. In addition, the observed different phases in the predicted stress–strain curve are validated with the literature data. Using the proposed numerical methodology, a detailed local stress–strain and damage analysis leads to an observation that the so-called ductile stress–strain behavior (kink in the stress–strain curve) of a CMC UD Laminate under uniaxial fiber direction tensile loads is mainly caused by the matrix damage initiation. Apart from the SiC material properties such as strength and fracture energy, it is also observed that the RVE size influences the average strength and failure strain predictions using computational micromechanics.
