Carbon Fiber Composites, Volume II

A special issue of Journal of Composites Science (ISSN 2504-477X). This special issue belongs to the section "Carbon Composites".

Deadline for manuscript submissions: closed (30 November 2022) | Viewed by 47831

Special Issue Editor


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Guest Editor
Oak Ridge National Laboratory, Oak Ridge, TN, USA
Interests: energy; polymers; fibers; biomaterials; low-dimensional materials
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Special Issue Information

Dear Colleagues,

Many efforts have been made to create light-weight materials that maintain excellent physical and chemical properties, aiming at energy savings and property enhancement for aerospace, automotive, marine, and industrial applications over the past few decades. Among them, carbon fibers and their composites have attracted significant attention because of their unique properties, including high strength and modulus, novel dimensional stability, high surface area/volume ratios, low coefficient of thermal expansion, etc. Therefore, they have been widely applied in fields of energy storage, filtration, aircraft, etc., via advanced manufacturing technologies (i.e., wet/melt spinning, solution casting, 3D printing, etc.).

Processing–structure–property relationships of carbon fibers and their composites are crucial for their future applications in the fields of energy, engineering, and the environment. Various precursors and processing approaches have been studied to prepare carbon fibers and composites with specific structures to achieve excellent multifunctional properties, consisting of better mechanical, thermal, electrical, and barrier properties. However, to date, lowering the manufacturing cost and expanding their applications remain challenging.

The main aim of this Special Issue is to tackle the points mentioned above for the preparation, characterization, and properties of advanced carbon fibers and their composites to offer an insight into them, facilitating their practical applications in various fields.

Dr. Jiadeng Zhu
Guest Editor

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Keywords

  • carbon fibers
  • carbon nanofibers
  • composites
  • filtration
  • energy
  • environment

Published Papers (18 papers)

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Research

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14 pages, 3591 KiB  
Article
Effect of MWCNT Anchoring to Para-Aramid Fiber Surface on the Thermal, Mechanical, and Impact Properties of Para-Aramid Fabric-Reinforced Vinyl Ester Composites
by Jinsil Cheon and Donghwan Cho
J. Compos. Sci. 2023, 7(10), 416; https://doi.org/10.3390/jcs7100416 - 6 Oct 2023
Cited by 1 | Viewed by 904
Abstract
In the present work, para-aramid fabrics (p-AF) were physically modified via an anchoring process of 0.05 wt% MWCNT to the aramid fiber surfaces by coating the MWCNT/phenolic/methanol mixture on p-AF, and then by thermally curing phenolic resin of 0.01 wt%. Para-aramid fabric-reinforced vinyl [...] Read more.
In the present work, para-aramid fabrics (p-AF) were physically modified via an anchoring process of 0.05 wt% MWCNT to the aramid fiber surfaces by coating the MWCNT/phenolic/methanol mixture on p-AF, and then by thermally curing phenolic resin of 0.01 wt%. Para-aramid fabric-reinforced vinyl ester (p-AF/VE) composites were fabricated using p-AF/VE prepregs by compression molding. The effect of MWCNT anchoring on the thermo-dimensional, thermal deflection resistant, dynamic mechanical, mechanical, and impact properties and the energy absorption behavior of p-AF/VE composites was extensively investigated in terms of coefficient of linear thermal expansion, heat deflection temperature, storage modulus, tan δ, tensile, flexural, and Izod impact properties and a drop-weight impact response. The results well agreed with each other, supporting the improved properties of p-AF/VE composites, which were attributed to the effect of MWCNT anchoring performed on the aramid fiber surfaces. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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13 pages, 5015 KiB  
Article
Mechanical and Thermal Properties of Multilayer-Coated 3D-Printed Carbon Fiber Reinforced Nylon Composites
by Hongwei Chen, Kaibao Wang, Yao Chen and Huirong Le
J. Compos. Sci. 2023, 7(7), 297; https://doi.org/10.3390/jcs7070297 - 20 Jul 2023
Cited by 2 | Viewed by 1179
Abstract
This paper evaluates the mechanical and thermal properties of 3D-printed short carbon fiber reinforced composites (sCFRPs). A numerical analysis was developed to predict the mechanical and thermal properties of the sCFRPs, which were verified via experimental tests. In the experiments, a novel technique [...] Read more.
This paper evaluates the mechanical and thermal properties of 3D-printed short carbon fiber reinforced composites (sCFRPs). A numerical analysis was developed to predict the mechanical and thermal properties of the sCFRPs, which were verified via experimental tests. In the experiments, a novel technique was adopted by coating the sCFRPs with carbon fiber fabric and copper mesh to further improve its mechanical and thermal performance. Various copper meshes (60-mesh, 100-mesh and 150-mesh) were integrated with carbon fiber fabric to form a multilayer structure, which was then coated on the surface of Nylon 12-CF composite material (base material) to form a composite plate. The effects of the copper mesh on the mechanical and thermal properties of the composite plate were studied theoretically and experimentally. The results show that the addition of different copper meshes had a significant influence on the mechanical and thermal properties of the composite plate, which contained carbon fiber fabric, copper mesh and the base material. Among them, the mechanical and thermal properties of the composite plate with the 60-mesh copper mesh were significantly improved, while the improvement effect slowly declined with the increase in the thickness of the base material. The composite plate with 100-mesh and 150-mesh copper meshes had improved mechanical properties, whereas the influence on its thermal conductivity was limited. For thermal conductivity calculation, both the thickness and length directions of the heat transfer were considered. The comparative analysis indicated that the calculated values and experimental results are in excellent agreement, meaning that this numerical model is a useful tool for guiding the design of surface lamination for 3D-printed sCFRPs. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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14 pages, 5845 KiB  
Article
Notched Behaviors of Carbon Fiber-Reinforced Epoxy Matrix Composite Laminates: Predictions and Experiments
by Shaoyong Cao, Yan Zhu and Yunpeng Jiang
J. Compos. Sci. 2023, 7(6), 223; https://doi.org/10.3390/jcs7060223 - 31 May 2023
Viewed by 1253
Abstract
This paper experimentally studied the influence of the notch shape and size on the damage evolution and failure strength (tension and torsion) of carbon fiber-reinforced epoxy matrix (CFRP) laminates. Hashin’s damage criteria were utilized to monitor the evolution of multi-damage modes, and FEM [...] Read more.
This paper experimentally studied the influence of the notch shape and size on the damage evolution and failure strength (tension and torsion) of carbon fiber-reinforced epoxy matrix (CFRP) laminates. Hashin’s damage criteria were utilized to monitor the evolution of multi-damage modes, and FEM simulations were also performed by using the ABAQUS code to clarify the specific damage modes in detail as an instructive complement. The failure characteristics of all the notched samples were analyzed and compared with those without notches. The measured results presented that the existence of a variety of notches significantly impaired the load carrying capacity of CFRP laminates. The tensile strengths of C-notch and U-notch increase with an increasing notch radius, while the ultimate torques of C-notch and V-notch decrease with an increasing notch size and angle. The variation in notched properties was explained by different notch shapes and sizes, and the failure characteristics were also presented and compared among notched CFRP laminates with varied notches. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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13 pages, 6400 KiB  
Article
The Effect of Pulse Current on Electrolytically Plating Nickel as a Catalyst for Grafting Carbon Nanotubes onto Carbon Fibers via the Chemical Vapor Deposition Method
by Kazuto Tanaka and Shuhei Kyoyama
J. Compos. Sci. 2023, 7(2), 88; https://doi.org/10.3390/jcs7020088 - 19 Feb 2023
Viewed by 1283
Abstract
Carbon nanotubes (CNTs) can be directly grafted onto the surface of carbon fibers using the chemical vapor deposition method, in which nanometer-order nickel (Ni) particles, serving as catalysts, are plated onto the surface of carbon fibers via electrolytic plating. In our previous studies, [...] Read more.
Carbon nanotubes (CNTs) can be directly grafted onto the surface of carbon fibers using the chemical vapor deposition method, in which nanometer-order nickel (Ni) particles, serving as catalysts, are plated onto the surface of carbon fibers via electrolytic plating. In our previous studies, in which a direct current (DC) was used to electrolytically plate Ni onto carbon fibers as a catalyst, the site densities and diameters of Ni particles increased simultaneously with the plating time, making it difficult to independently control the site densities and diameters of the particles. On the other hand, pulse current (PC) plating is attracting attention as a plating technique that can control the deposition morphology of nuclei. In this study, we clarify the effect of the parameters of the PC on the particle number per unit area (site density) and the particle diameters of Ni particles plated onto the surface of carbon fibers, using the PC to electrolytically plate Ni. Electrolytically plating Ni onto carbon fibers (via PC) after the removal of the sizing agent enable Ni particles with sparser site densities and larger diameters to be plated than those plated via DC. Using Ni particles with sparse site densities, it is shown that CNTs with sparse site densities can be grafted. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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13 pages, 3853 KiB  
Article
Self-Sensing Eco-Earth Composite with Carbon Microfibers for Sustainable Smart Buildings
by Hasan Borke Birgin, Antonella D’Alessandro, Andrea Meoni and Filippo Ubertini
J. Compos. Sci. 2023, 7(2), 63; https://doi.org/10.3390/jcs7020063 - 6 Feb 2023
Cited by 9 | Viewed by 1830
Abstract
This paper proposes a new sustainable earth–cement building composite with multifunctional sensing features and investigates its properties through an experimental campaign. Earth and cement are proportioned as 2/7 in volume, while carbon microfibers are added in various amounts to achieve piezoresistivity, ranging from [...] Read more.
This paper proposes a new sustainable earth–cement building composite with multifunctional sensing features and investigates its properties through an experimental campaign. Earth and cement are proportioned as 2/7 in volume, while carbon microfibers are added in various amounts to achieve piezoresistivity, ranging from 0 to 1% with respect to the weight of the binder (i.e., earth + cement). The proposed material couples the construction performance with self-sensing properties in order to monitor the structural performance during the servile life of the building. The use of earth in the partial replacement of cement reduces the environmental footprint of the material while keeping sufficient mechanical properties, at least for applications that do not require a large load-bearing capacity (e.g., for plasters or for low-rise constructions). This paper analyzes the electrical and sensing behavior of cubic and beam samples through electrical and electromechanical tests. The results show that the samples with a filler percentage near the percolation zone, ranged between 0.025 and 0.25%, exhibit the best performance. From the cyclical compressive tests and linear developed models, it could be deduced that the filler content of 0.05% of carbon fibers, with respect to the binder weight, represents the best-performing smart composite for further investigation at higher scales. As demonstrated, the selected mix generated clear strain-sensing electrical signals, reaching gauge factors over 100. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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20 pages, 6487 KiB  
Article
Microstructural Analysis of the Transverse and Shear Behavior of Additively Manufactured CFRP Composite RVEs Based on the Phase-Field Fracture Theory
by Matej Gljušćić, Domagoj Lanc, Marina Franulović and Andrej Žerovnik
J. Compos. Sci. 2023, 7(1), 38; https://doi.org/10.3390/jcs7010038 - 12 Jan 2023
Cited by 1 | Viewed by 1878
Abstract
Due to the versatility of its implementation, additive manufacturing has become the enabling technology in the research and development of innovative engineering components. However, many experimental studies have shown inconsistent results and have highlighted multiple defects in the materials’ structure thus bringing the [...] Read more.
Due to the versatility of its implementation, additive manufacturing has become the enabling technology in the research and development of innovative engineering components. However, many experimental studies have shown inconsistent results and have highlighted multiple defects in the materials’ structure thus bringing the adoption of the additive manufacturing method in practical engineering applications into question, yet limited work has been carried out in the material modelling of such cases. In order to account for the effects of the accumulated defects, a micromechanical analysis based on the representative volume element has been considered, and phase-field modelling has been adopted to model the effects of inter-fiber cracking. The 3D models of representative volume elements were developed in the Abaqus environment based on the fiber dimensions and content acquired using machine learning algorithms, while fulfilling both geometric and material periodicity. Furthermore, the periodic boundary conditions were assumed for each of the representative volume elements in transversal and in-plane shear test cases,. The analysis was conducted by adopting an open-source UMAT subroutine, where the phase-field balance equation was related to the readily available heat transfer equation from Abaqus, avoiding the necessity for a dedicated user-defined element thus enabling the adoption of the standard elements and features available in the Abaqus CAE environment. The model was tested on three representative volume element sizes and the interface properties were calibrated according to the experimentally acquired results for continuous carbon-fiber-reinforced composites subjected to transverse tensile and shear loads. This investigation confirmed the consistency between the experimental results and the numerical solutions acquired using a phase-field fracture approach for the transverse tensile and shear behavior of additively manufactured continuous-fiber-reinforced composites, while showing dependence on the representative volume element type for distinctive load cases. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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12 pages, 2875 KiB  
Article
Optimization of Electrical Intensity for Electrochemical Anodic Oxidation to Modify the Surface of Carbon Fibers and Preparation of Carbon Nanotubes/Carbon Fiber Multi-Scale Reinforcements
by Mengfan Li, Yanxiang Wang, Bowen Cui, Chengjuan Wang, Hongxue Tan, Haotian Jiang, Zhenhao Xu, Chengguo Wang and Guangshan Zhuang
J. Compos. Sci. 2022, 6(12), 395; https://doi.org/10.3390/jcs6120395 - 18 Dec 2022
Viewed by 1442
Abstract
Carbon fiber (CF) reinforced composites are widely used due to their excellent properties. However, the smooth surface and few functional groups of CFs can lead to fiber fractures and pullout, which reduce the service life of the composites. The overall performance of composites [...] Read more.
Carbon fiber (CF) reinforced composites are widely used due to their excellent properties. However, the smooth surface and few functional groups of CFs can lead to fiber fractures and pullout, which reduce the service life of the composites. The overall performance of composites can be improved by growing carbon nanotubes (CNTs) on the CF surface. Before this, CF surface should be modified to enhance the loading amount of catalyst particles and thus make the CNTs more uniform. In this paper, CNTs were grown on a CF surface by one-step chemical vapor deposition to prepare multi-scale CNTs/CF reinforcements, and the effects of different methods on the CF surface modification were explored. After setting four intensities of electrochemical anodic oxidation, i.e., 50 C/g, 100 C/g, 150 C/g and 200 C/g, it was found that the distribution and quantity of CNTs were improved under both the 100 C/g and 150 C/g conditions. Considering the influence of electrical intensity on the (002) interplanar spacing of CFs, which affects the mechanical properties of the samples, 100 C/g was finally selected as the optimal electrochemical treatment intensity. This finding provides a reference for continuous and large-scale modification of CF surfaces to prepare CNTs/CF multi-scale reinforcements. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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16 pages, 8267 KiB  
Article
Surface Damage in Woven Carbon Composite Panels under Orthogonal and Inclined High-Velocity Impacts
by Veronica Marchante Rodriguez, Marzio Grasso, Yifan Zhao, Haochen Liu, Kailun Deng, Andrew Roberts and Gareth James Appleby-Thomas
J. Compos. Sci. 2022, 6(10), 282; https://doi.org/10.3390/jcs6100282 - 26 Sep 2022
Cited by 2 | Viewed by 1666
Abstract
The present research is aimed at the study of the failure analysis of composite panels impacted orthogonally at a high velocity and with an angle. Woven carbon-fibre panels with and without external Kevlar layers were impacted at different energy levels between 1.2 and [...] Read more.
The present research is aimed at the study of the failure analysis of composite panels impacted orthogonally at a high velocity and with an angle. Woven carbon-fibre panels with and without external Kevlar layers were impacted at different energy levels between 1.2 and 39.9 J. Sharp and smooth gravels with a mass from 3.1 to 6.7 g were used to investigate the effects of the mass and the contact area on the damage. Optical microscopy and thermography analyses were carried out to identify internal and surface damage. It was identified that sharp impactors created more damage on the impacted face of the panels, while the presence of a Kevlar layer increased the penetration limit and reduced the damage level in the panel at a higher energy. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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17 pages, 4636 KiB  
Article
Mechanical Response and Processability of Wet-Laid Recycled Carbon Fiber PE, PA66 and PET Thermoplastic Composites
by Uday Vaidya, Mark Janney, Keith Graham, Hicham Ghossein and Merlin Theodore
J. Compos. Sci. 2022, 6(7), 198; https://doi.org/10.3390/jcs6070198 - 7 Jul 2022
Cited by 1 | Viewed by 1871
Abstract
The interest in recycled carbon fiber (rCF) is growing rapidly and the supply chain for these materials is gradually being established. However, the processing routes, material intermediates and properties of rCF composites are less understood for designers to adopt them into practice. This [...] Read more.
The interest in recycled carbon fiber (rCF) is growing rapidly and the supply chain for these materials is gradually being established. However, the processing routes, material intermediates and properties of rCF composites are less understood for designers to adopt them into practice. This paper provides a practical pathway for rCFs in conjunction with low cost and, for the most part, commodity thermoplastic resins, namely polyethylene (PE), polyamide 66 (PA66) and polyethylene terephthalate (PET). Industrially relevant wet-laid (WL) process routes have been adopted to produce mats using two variants of WL mats, namely (a) high speed wet-laid inclined wire to produce broad good ‘roll’ forms and (b) 3DEPTM process patented by Materials Innovation Technologies (MIT)-recycled carbon fiber (RCF), now Carbon Conversions, which involves mixing fibers and water and depositing the fibers on a water-immersed mold. These are referred to as ‘sheet’ forms. The produced mats were evaluated for their processing into composites as ‘fully consolidated mats’ and ‘non-consolidated’ as-produced mats. Comprehensive mechanical data in terms of tensile strength, tensile modulus and impact toughness for rCF C/PE, C/PA66 and C/PET are presented. The work is of high value to sustainable composite designers and modelers. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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29 pages, 11492 KiB  
Article
Static and Vibration Analyses of a Composite CFRP Robot Manipulator
by Mohammad Amir Khozeimeh, Reza Fotouhi and Reza Moazed
J. Compos. Sci. 2022, 6(7), 196; https://doi.org/10.3390/jcs6070196 - 4 Jul 2022
Cited by 2 | Viewed by 1907
Abstract
This paper reports analyses of a 5-degrees-of-freedom (5-DOF) carbon fiber-reinforced polymer (CFRP) robot manipulator, which has been developed for farm applications. The manipulator was made of aluminum alloy (AA) and steel materials. However, to check the effectiveness of CFRP materials on the static [...] Read more.
This paper reports analyses of a 5-degrees-of-freedom (5-DOF) carbon fiber-reinforced polymer (CFRP) robot manipulator, which has been developed for farm applications. The manipulator was made of aluminum alloy (AA) and steel materials. However, to check the effectiveness of CFRP materials on the static and free-vibration performance of the manipulator, the AA parts were replaced with CFRP. For this purpose, the effects of various cross-sections and layups on three design criteria—deflection, load-carrying capacity, and natural frequency—were investigated. Two types of thin-walled laminated sections, specifically the I section and rectangular tubular sections, were used for the composite parts. These parts were made from three hollow square section (“SSS” section) beams and three I section (“III” section) beams. These multi-cell beams were modeled using the finite element (FE) method. Three configurations were selected for analysis based on the manipulator’s most common operating conditions. The results indicated that the use of CFRP increased the manipulator’s natural frequencies, increased the load-carrying capacity, and decreased the manipulator’s tip deflection when compared with its AA counterpart. An analysis showed that using CFRP in the manipulator’s structure could improve static and vibrational performances. It was observed that the “SSS” section beams were 1.17 times stiffer, could carry a 1.20 times higher load, and were 1.40 times heavier than the “III” section beams. Also, decreasing the fiber direction in angle-ply layups from 90° to 0° and adding 0° plies, while keeping the total number of layers constant, decreased the manipulator’s tip deflection and increased its natural frequencies. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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16 pages, 7646 KiB  
Article
The Machinability Characteristics of Multidirectional CFRP Composites Using High-Performance Wire EDM Electrodes
by Ramy Abdallah, Richard Hood and Sein Leung Soo
J. Compos. Sci. 2022, 6(6), 159; https://doi.org/10.3390/jcs6060159 - 27 May 2022
Cited by 5 | Viewed by 2456
Abstract
Due to the abrasive nature of the material, the conventional machining of CFRP composites is typically characterised by high mechanical forces and poor tool life, which can have a detrimental effect on workpiece surface quality, mechanical properties, dimensional accuracy, and, ultimately, functional performance. [...] Read more.
Due to the abrasive nature of the material, the conventional machining of CFRP composites is typically characterised by high mechanical forces and poor tool life, which can have a detrimental effect on workpiece surface quality, mechanical properties, dimensional accuracy, and, ultimately, functional performance. The present paper details an experimental investigation to assess the feasibility of wire electrical discharge machining (WEDM) as an alternative for cutting multidirectional CFRP composite laminates using high-performance wire electrodes. A full factorial experimental array comprising a total of 8 tests was employed to evaluate the effect of varying ignition current (3 and 5 A), pulse-off time (8 and 10 µs), and wire type (Topas Plus D and Compeed) on material removal rate (MRR), kerf width, workpiece surface roughness, and surface damage. The Compeed wire achieved a lower MRR of up to ~40% compared with the Topas wire when operating at comparable cutting parameters, despite having a higher electrical conductivity. Statistical investigation involving analysis of variance (ANOVA) showed that the pulse-off time was the only significant factor impacting the material removal rate, with a percentage contribution ratio of 67.76%. In terms of cut accuracy and surface quality, machining with the Compeed wire resulted in marginally wider kerfs (~8%) and a higher workpiece surface roughness (~11%) compared to the Topas wire, with maximum recorded values of 374.38 µm and 27.53 µm Sa, respectively. Micrographs from scanning electron microscopy revealed the presence of considerable fibre fragments, voids, and adhered re-solidified matrix material on the machined surfaces, which was likely due to the thermal nature of the WEDM process. The research demonstrated the viability of WEDM for cutting relatively thick (9 mm) multidirectional CFRP laminates without the need for employing conductive assistive electrodes. The advanced coated wire electrodes used in combination with higher ignition current and lower pulse-off time levels resulted in an increased MRR of up to ~15 mm3/min. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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21 pages, 7775 KiB  
Article
Experimental Analysis of Residual Stresses in CFRPs through Hole-Drilling Method: The Role of Stacking Sequence, Thickness, and Defects
by Tao Wu, Roland Kruse, Steffen Tinkloh, Thomas Tröster, Wolfgang Zinn, Christian Lauhoff and Thomas Niendorf
J. Compos. Sci. 2022, 6(5), 138; https://doi.org/10.3390/jcs6050138 - 9 May 2022
Cited by 1 | Viewed by 2382
Abstract
Carbon fiber reinforced plastics (CFRPs) gained high interest in industrial applications because of their excellent strength and low specific weight. The stacking sequence of the unidirectional plies forming a CFRP laminate, and their thicknesses, primarily determine the mechanical performance. However, during manufacturing, defects, [...] Read more.
Carbon fiber reinforced plastics (CFRPs) gained high interest in industrial applications because of their excellent strength and low specific weight. The stacking sequence of the unidirectional plies forming a CFRP laminate, and their thicknesses, primarily determine the mechanical performance. However, during manufacturing, defects, e.g., pores and residual stresses, are induced, both affecting the mechanical properties. The objective of the present work is to accurately measure residual stresses in CFRPs as well as to investigate the effects of stacking sequence, overall laminate thickness, and the presence of pores on the residual stress state. Residual stresses were measured through the incremental hole-drilling method (HDM). Adequate procedures have been applied to evaluate the residual stresses for orthotropic materials, including calculating the calibration coefficients through finite element analysis (FEA) based on stacking sequence, laminate thickness and mechanical properties. Using optical microscopy (OM) and computed tomography (CT), profound insights into the cross-sectional and three-dimensional microstructure, e.g., location and shape of process-induced pores, were obtained. This microstructural information allowed for a comprehensive understanding of the experimentally determined strain and stress results, particularly at the transition zone between the individual plies. The effect of pores on residual stresses was investigated by considering pores to calculate the calibration coefficients at a depth of 0.06 mm to 0.12 mm in the model and utilizing these results for residual stress evaluation. A maximum difference of 46% in stress between defect-free and porous material sample conditions was observed at a hole depth of 0.65 mm. The significance of employing correctly calculated coefficients for the residual stress evaluation is highlighted by mechanical validation tests. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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33 pages, 7580 KiB  
Article
Tailoring the Local Design of Deep Water Composite Risers to Minimise Structural Weight
by Chiemela Victor Amaechi, Nathaniel Gillet, Idris Ahmed Ja’e and Chunguang Wang
J. Compos. Sci. 2022, 6(4), 103; https://doi.org/10.3390/jcs6040103 - 26 Mar 2022
Cited by 11 | Viewed by 3001
Abstract
Following the rising technological advancements on composite marine structures, there is a corresponding surge in the demand for its deployment as ocean engineering applications. The push for exploration activities in deep waters necessitates the need for composite marine structures to reduce structural payload [...] Read more.
Following the rising technological advancements on composite marine structures, there is a corresponding surge in the demand for its deployment as ocean engineering applications. The push for exploration activities in deep waters necessitates the need for composite marine structures to reduce structural payload and lessen weights/loads on platform decks. This gain is achieved by its high strength–stiffness modulus and light-in-weight attributes, enabling easier marine/offshore operations. Thus, the development of composite marine risers considers critical composite characteristics to optimize marine risers’ design. Hence, an in-depth study on composite production risers (CPR) is quite pertinent in applying composite materials to deep water applications. Two riser sections of 3 m and 5 m were investigated under a 2030 m water depth environment to minimise structural weight. ANSYS Composites ACP was utilized for the CPR’s finite element model (FEM) under different load conditions. The choice of the material, the fibre orientation, and the lay-up configurations utilised in the modelling technique have been reported. In addition, the behaviour of the composite risers’ layers under four loadings has been investigated under marine conditions. Recommendations were made for the composite tubular structure. Results on stresses and weight savings were obtained from different composite riser configurations. The recommended composite riser design that showed the best performance is AS4/PEEK utilising PEEK liner, however more work is suggested using global design loadings on the CPR. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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15 pages, 5020 KiB  
Article
Influence of Line Processing Parameters on Properties of Carbon Fibre Epoxy Towpreg
by Murat Çelik, Thomas Noble, Frank Jorge, Rongqing Jian, Conchúr M. Ó Brádaigh and Colin Robert
J. Compos. Sci. 2022, 6(3), 75; https://doi.org/10.3390/jcs6030075 - 2 Mar 2022
Cited by 7 | Viewed by 3361
Abstract
This paper explores the performance of low-cost unidirectional carbon fibre towpregs with respect to line production speed and fibre volume fraction. Using an automated production line, towpregs were produced at different production speeds, resulting in modified fibre volume fractions. The towpregs were used [...] Read more.
This paper explores the performance of low-cost unidirectional carbon fibre towpregs with respect to line production speed and fibre volume fraction. Using an automated production line, towpregs were produced at different production speeds, resulting in modified fibre volume fractions. The towpregs were used to manufacture unidirectional composite plates, which were then tested to evaluate mechanical performance. The fibre straightness and interfacial void ratio of the composite plates were determined by statistical analysis of the samples’ optical micrographs. The results demonstrate that adjusting the line production speed enables targeted fibre volume fractions (FVF) to be reached, resulting in the composites having different mechanical performances (2039 MPa and 2186.7 MPa tensile strength, 1.26 and 1.21 GPa flexural strength for 59.8% and 64.4% FVF, respectively). It was shown that at lower production speeds and FVF, composites exhibit good consolidation and low porosity, which is highlighted by the better interlaminar shear strength performances (8.95% increase), indicating the limitations of manufacturing very high FVF composites. Furthermore, it was concluded that fibre straightness plays a key role in mechanical performance, as samples with a lesser degree of fibre straightness showed a divergence from theoretical tensile properties. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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18 pages, 5188 KiB  
Article
Performance of Two-Way Concrete Slabs Reinforced with Basalt and Carbon FRP Rebars
by Sukanta Kumer Shill, Estela O. Garcez, Riyadh Al-Ameri and Mahbube Subhani
J. Compos. Sci. 2022, 6(3), 74; https://doi.org/10.3390/jcs6030074 - 1 Mar 2022
Cited by 9 | Viewed by 3660
Abstract
Fibre-reinforced polymer (FRP) rebars are being increasingly used to reinforce concrete structures that require long-term resistance to a corrosive environment. This study presents structural performance of large scale two-way concrete slabs reinforced with FRP rebars, and their performances were compared against conventional steel [...] Read more.
Fibre-reinforced polymer (FRP) rebars are being increasingly used to reinforce concrete structures that require long-term resistance to a corrosive environment. This study presents structural performance of large scale two-way concrete slabs reinforced with FRP rebars, and their performances were compared against conventional steel reinforced concrete. Both carbon FRP (CFRP) and basalt FRP (BFRP) were considered as steel replacement. Experimental results showed that the CFRP- and BFRP-RC slabs had approximately 7% and 4% higher cracking moment capacities than the steel-RC slab, respectively. The BFRP-RC slabs experienced a gradual decrease in the load capacity beyond the peak load, whereas the CFRP-RC slabs underwent a sharp decrease in load capacity, similar to the steel-RC slab. The BFRP-RC slabs demonstrated 1.72 times higher ductility than CFRP-RC slabs. The steel-RC slab was found to be safe against punching shear but failed due to flexural bending moment. The FRP-RC slabs were adequately safe against bending moment but failed due to punching shear. At failure load, the steel rebars were found to be yielded; however, the FRP rebars were not ruptured. FRP-RC slabs experienced a higher number of cracks and higher deflection compared to the steel-RC slab. However, FRP-RC slabs exhibited elastic recovery while unloading. Elastic recovery was not observed in the steel-RC slab. Additionally, the analytical load carrying capacity was validated against experimental values to investigate the efficacy of the current available standards (ACI 318-14 and ACI 440.1R-15) to predict the capacity of a two-way slab reinforced with CFRP or BFRP. The experimental load capacity of the CFRP-RC slabs was found to be approximately 1.20 times higher than the theoretical ultimate load capacity. However, the experimental load capacity of the BFRP-RC slabs was 6% lower than their theoretical ultimate load capacity. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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10 pages, 2040 KiB  
Article
Modeling Flexural Failure in Carbon-Fiber-Reinforced Polymer Composites
by Thiago de Sousa Burgani, Seyedhamidreza Alaie and Mehran Tehrani
J. Compos. Sci. 2022, 6(2), 33; https://doi.org/10.3390/jcs6020033 - 19 Jan 2022
Cited by 3 | Viewed by 2847
Abstract
Flexural testing provides a rapid and straightforward assessment of fiber-reinforced composites’ performance. In many high-strength composites, flexural strength is higher than compressive strength. A finite-element model was developed to better understand this improvement in load-bearing capability and to predict the flexural strength of [...] Read more.
Flexural testing provides a rapid and straightforward assessment of fiber-reinforced composites’ performance. In many high-strength composites, flexural strength is higher than compressive strength. A finite-element model was developed to better understand this improvement in load-bearing capability and to predict the flexural strength of three different carbon-fiber-reinforced polymer composite systems. The model is validated against publicly available experimental data and verified using theory. Different failure criteria are evaluated with respect to their ability to predict the strength of composites under flexural loading. The Tsai–Wu criterion best explains the experimental data. An expansion in compressive stress limit for all three systems was observed and is explained by the compression from the loading roller and Poisson’s effects. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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12 pages, 3327 KiB  
Article
Damping Properties of Hybrid Composites Made from Carbon, Vectran, Aramid and Cellulose Fibers
by Hauke Kröger, Stephan Mock, Christoph Greb and Thomas Gries
J. Compos. Sci. 2022, 6(1), 13; https://doi.org/10.3390/jcs6010013 - 31 Dec 2021
Cited by 10 | Viewed by 2130
Abstract
Hybridization of carbon fiber composites can increase the material damping of composite parts. However, there is little research on a direct comparison of different fiber materials—particularly for carbon fiber intraply-hybrid composites. Hence, the mechanical- and damping properties of different carbon fiber intraply hybrids [...] Read more.
Hybridization of carbon fiber composites can increase the material damping of composite parts. However, there is little research on a direct comparison of different fiber materials—particularly for carbon fiber intraply-hybrid composites. Hence, the mechanical- and damping properties of different carbon fiber intraply hybrids are analyzed in this paper. Quasi unidirectional fabrics made of carbon, aramid, Vectran and cellulose fibers are produced, and their mechanical properties are analyzed. The material tests show an increased material damping due to the use of Vectran and aramid fibers, with a simultaneous reduction in strength and stiffness. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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Review

Jump to: Research

50 pages, 17899 KiB  
Review
Review of Composite Marine Risers for Deep-Water Applications: Design, Development and Mechanics
by Chiemela Victor Amaechi, Cole Chesterton, Harrison Obed Butler, Nathaniel Gillet, Chunguang Wang, Idris Ahmed Ja’e, Ahmed Reda and Agbomerie Charles Odijie
J. Compos. Sci. 2022, 6(3), 96; https://doi.org/10.3390/jcs6030096 - 17 Mar 2022
Cited by 19 | Viewed by 11666
Abstract
In recent times, the utilisation of marine composites in tubular structures has grown in popularity. These applications include composite risers and related SURF (subsea umbilicals, risers and flowlines) units. The composite industry has evolved in the development of advanced composites, such as thermoplastic [...] Read more.
In recent times, the utilisation of marine composites in tubular structures has grown in popularity. These applications include composite risers and related SURF (subsea umbilicals, risers and flowlines) units. The composite industry has evolved in the development of advanced composites, such as thermoplastic composite pipes (TCP) and hybrid composite structures. However, there are gaps in the understanding of its performance in composite risers, hence the need for this review on the design, hydrodynamics and mechanics of composite risers. The review covers both the structure of the composite production riser (CPR) and its end-fittings for offshore marine applications. It also reviews the mechanical behaviour of composite risers, their microstructure and strength/stress profiles. In principle, designers now have a greater grasp of composite materials. It was concluded that composites differ from standard materials such as steel. Basically, composites have weight savings and a comparative stiffness-to-strength ratio, which are advantageous in marine composites. Also, the offshore sector has grown in response to newer innovations in composite structures such as composite risers, thereby providing new cost-effective techniques. This comprehensive review shows the necessity of optimising existing designs of composite risers. Conclusions drawn portray issues facing composite riser research. Recommendations were made to encourage composite riser developments, including elaboration of necessary standards and specifications. Full article
(This article belongs to the Special Issue Carbon Fiber Composites, Volume II)
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