Mechanical Properties of a Biocomposite Based on Carbon Nanotube and Graphene Nanoplatelet Reinforced Polymers: Analytical and Numerical Study

Biocomposites based on thermoplastic polymers and natural fibers have recently been used in wind turbine blades, to replace non-biodegradable materials. In addition, carbon nanofillers, including carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are being implemented to enhance the mechanical performance of composites. In this work, the Mori–Tanaka approach is used for homogenization of a polymer matrix reinforced by CNT and GNP nanofillers for the first homogenization, and then, for the second homogenization, the effective matrix was used with alfa and E-glass isotropic fibers. The objective is to study the influence of the volume fraction Vf and aspect ratio AR of nanofillers on the elastic properties of the composite. The inclusions are considered in a unidirectional and random orientation by using a computational method by Digimat-MF/FE and analytical approaches by Chamis, Hashin–Rosen and Halpin–Tsai. The results show that CNT- and GNP-reinforced nanocomposites have better performance than those without reinforcement. Additionally, by increasing the volume fraction and aspect ratio of nanofillers, Young’s modulus E increases and Poisson’s ratio ν decreases. In addition, the composites have enhanced mechanical characteristics in the longitudinal orientation for CNT- reinforced polymer and in the transversal orientation for GNP-reinforced polymer.

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Mechanical Properties of Boehmeria nivea Natural Fabric Reinforced Epoxy Matrix Composite Prepared by Vacuum-Assisted Resin Infusion Molding

Polymers ◽

10.3390/polym12061311 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1311 ◽

Cited By ~ 1

Author(s):

Fabio da Costa Garcia Filho ◽

Fernanda Santos da Luz ◽

Lucio Fabio Cassiano Nascimento ◽

Kestur Gundappa Satyanarayana ◽

Jaroslaw Wieslaw Drelich ◽

...

Keyword(s):

Mechanical Performance ◽

Volume Fraction ◽

Natural Fibers ◽

Ramie Fiber ◽

Resin Infusion ◽

Lignocellulosic Fibers ◽

Boehmeria Nivea ◽

Fabric Composites ◽

Epoxy Matrix Composite ◽

Efficient Alternative

Natural lignocellulosic fibers and corresponding fabrics have been gaining notoriety in recent decades as reinforcement options for polymer matrices associated with industrially applied composites. These natural fibers and fabrics exhibit competitive properties when compared with some synthetics such as glass fiber. In particular, the use of fabrics made from natural fibers might be considered a more efficient alternative, since they provide multidirectional reinforcement and allow the introduction of a larger volume fraction of fibers in the composite. In this context, it is important to understand the mechanical performance of natural fabric composites as a basic condition to ensure efficient engineering applications. Therefore, it is also important to recognize that ramie fiber exhibiting superior strength can be woven into fabric, but is the least investigated as reinforcement in strong, tough polymers to obtain tougher polymeric composites. Accordingly, this paper presents the preparation of epoxy composite containing 30 vol.% Boehmeria nivea fabric by vacuum-assisted resin infusion molding technique and mechanical behavior characterization of the prepared composite. Obtained results are explained based on the fractography studies of tested samples.

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Comparison of Analytical Approaches Predicting the Compressive Strength of Fibre Reinforced Polymers

Materials ◽

10.3390/ma11122517 ◽

2018 ◽

Vol 11 (12) ◽

pp. 2517 ◽

Cited By ~ 4

Author(s):

Christian Leopold ◽

Sergej Harder ◽

Timo Philipkowski ◽

Wilfried Liebig ◽

Bodo Fiedler

Keyword(s):

Compressive Strength ◽

Prediction Accuracy ◽

Volume Fraction ◽

Fibre Volume Fraction ◽

Experimental Results ◽

Analytical Models ◽

Reinforced Polymers ◽

Reinforced Polymer ◽

Fibre Reinforced Polymer ◽

Analytical Approaches

Common analytical models to predict the unidirectional compressive strength of fibre reinforced polymers are analysed in terms of their accuracy. Several tests were performed to determine parameters for the models and the compressive strength of carbon fibre reinforced polymer (CFRP) and glass fibre reinforced polymer (GFRP). The analytical models are validated for composites with glass and carbon fibres by using the same epoxy matrix system in order to examine whether different fibre types are taken into account. The variation in fibre diameter is smaller for CFRP. The experimental results show that CFRP has about 50% higher compressive strength than GFRP. The models exhibit significantly different results. In general, the analytical models are more precise for CFRP. Only one fibre kinking model’s prediction is in good agreement with the experimental results. This is in contrast to previous findings, where a combined modes model achieves the best prediction accuracy. However, in the original form, the combined modes model is not able to predict the compressive strength for GFRP and was adapted to address this issue. The fibre volume fraction is found to determine the dominating failure mechanisms under compression and thus has a high influence on the prediction accuracy of the various models.

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Numerical study of the structural static and fatigue strength of wind turbine blades

Materials Today Proceedings ◽

10.1016/j.matpr.2019.04.090 ◽

2019 ◽

Vol 13 ◽

pp. 1215-1223 ◽

Cited By ~ 1

Author(s):

M. Tarfaoui ◽

M. Nachtane ◽

O.R. Shah ◽

H. Boudounit

Keyword(s):

Fatigue Strength ◽

Wind Turbine ◽

Numerical Study ◽

Turbine Blades ◽

Wind Turbine Blades

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Fiber Diameter-Dependent Elastic Deformation in Polymer Composites—A Numerical Study

Journal of Engineering Materials and Technology ◽

10.1115/1.4043766 ◽

2019 ◽

Vol 142 (1) ◽

Cited By ~ 1

Author(s):

Nitin Garg ◽

Gurudutt Chandrashekar ◽

Farid Alisafaei ◽

Chung-Souk Han

Keyword(s):

Mechanical Behavior ◽

Polymer Composites ◽

Elastic Deformation ◽

Volume Fraction ◽

Fiber Diameter ◽

Scale Effects ◽

Numerical Study ◽

Length Scale ◽

Fiber Volume ◽

Reinforced Polymer

Abstract Microbeam bending and nano-indentation experiments illustrate that length scale-dependent elastic deformation can be significant in polymers at micron and submicron length scales. Such length scale effects in polymers should also affect the mechanical behavior of reinforced polymer composites, as particle sizes or diameters of fibers are typically in the micron range. Corresponding experiments on particle-reinforced polymer composites have shown increased stiffening with decreasing particle size at the same volume fraction. To examine a possible linkage between the size effects in neat polymers and polymer composites, a numerical study is pursued here. Based on a couple stress elasticity theory, a finite element approach for plane strain problems is applied to predict the mechanical behavior of fiber-reinforced epoxy composite materials at micrometer length scale. Numerical results show significant changes in the stress fields and illustrate that with a constant fiber volume fraction, the effective elastic modulus increases with decreasing fiber diameter. These results exhibit similar tendencies as in mechanical experiments of particle-reinforced polymer composites.

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Lightning strike thermal damage model for glass fiber reinforced polymer matrix composites and its application to wind turbine blades

Composite Structures ◽

10.1016/j.compstruct.2015.07.027 ◽

2015 ◽

Vol 132 ◽

pp. 1182-1191 ◽

Cited By ~ 42

Author(s):

Y. Wang ◽

O.I. Zhupanska

Keyword(s):

Thermal Damage ◽

Polymer Matrix Composites ◽

Turbine Blades ◽

Damage Model ◽

Fiber Reinforced Polymer ◽

Lightning Strike ◽

Matrix Composites ◽

Wind Turbine Blades ◽

Reinforced Polymer ◽

Glass Fiber Reinforced

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State-of-the-art models for mechanical performance of carbon-glass hybrid composites in wind turbine blades

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/942/1/012005 ◽

2020 ◽

Vol 942 ◽

pp. 012005

Author(s):

Yentl Swolfs ◽

Babak Fazlali ◽

Arsen Melnikov ◽

Francisco Mesquita ◽

Vincent Feyen ◽

...

Keyword(s):

Wind Turbine ◽

Mechanical Performance ◽

State Of The Art ◽

Hybrid Composites ◽

Turbine Blades ◽

Wind Turbine Blades

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Polyurethane derived from castor oil reinforced with long cotton fibers: Static and dynamic testing of a novel eco-friendly composite material

Journal of Composite Materials ◽

10.1177/0021998320911984 ◽

2020 ◽

Vol 54 (22) ◽

pp. 3125-3142

Author(s):

Romeu RC da Costa ◽

Eduardo S Sato ◽

Marcelo L Ribeiro ◽

Ricardo de Medeiros ◽

André FC Vieira ◽

...

Keyword(s):

Composite Material ◽

Castor Oil ◽

Failure Modes ◽

Mechanical Performance ◽

Volume Fraction ◽

Glass Fibers ◽

Natural Fibers ◽

Dynamic Responses ◽

Cotton Fibers ◽

The Novel

A novel eco-friendly composite material made of polyurethane derived from castor oil reinforced with long cotton fibers was developed. A set of comparative analyses comprising static and dynamic tests was established using specimens made of castor oil-based polyurethane reinforced by glass fibers, and epoxy reinforced by glass and cotton fibers. The manufacturing method and estimation of fiber volume fraction of the specimens were described in detail. Tensile and flexural tests were performed to evaluate the mechanical performance of the novel laminate. Fractographic post-mortem examinations assessed the quality of the fiber–matrix interaction and allowed direct observation of the failure modes. Surface treatment of natural fibers appears necessary to improve the adhesion of the natural fibers to the matrix. Dynamic responses are discussed, considering natural frequencies and modal damping coefficients. In this context, the potentialities and the limitations of using the novel eco-friendly composite material as structural parts are discussed.

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Experimental Investigation of Finite Aspect Ratio Cylindrical Bodies for Accelerated Wind Applications

Fluids ◽

10.3390/fluids5010025 ◽

2020 ◽

Vol 5 (1) ◽

pp. 25 ◽

Cited By ~ 1

Author(s):

Michael Parker ◽

Douglas Bohl

Keyword(s):

Aspect Ratio ◽

Wind Turbine ◽

Turbine Blades ◽

Cylindrical Body ◽

Turbine Rotor ◽

Flow Speed ◽

The Body ◽

Rotor Blades ◽

Wind Turbine Blades ◽

Smooth Cylinder

The placement of a cylindrical body in a flow alters the velocity and pressure fields resulting in a local increase in the flow speed near the body. This interaction is of interest as wind turbine rotor blades could be placed in the area of increased wind speed to enhance energy harvesting. In this work the aerodynamic performance of two short aspect ratio (AR = 0.93) cylindrical bodies was evaluated for potential use in “accelerated wind” applications. The first cylinder was smooth with a constant diameter. The diameter of the second cylinder varied periodically along the span forming channels, or corrugations, where wind turbine blades could be placed. Experiments were performed for Reynolds numbers ranging from 1 × 105 to 9 × 105. Pressure distributions showed that the smooth cylinder had lower minimum pressure coefficients and delayed separation compared to the corrugated cylinder. Velocity profiles showed that the corrugated cylinder had lower peak speeds, a less uniform profile, and lower kinetic energy flux when compared to the smooth cylinder. It was concluded that the smooth cylinder had significantly better potential performance in accelerated wind applications than the corrugated cylinder.

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