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J. Compos. Sci., Volume 6, Issue 4 (April 2022) – 19 articles

Cover Story (view full-size image): Combining eco-sustainability and technological efficiency is one of the “hot” topics in the current construction and architectural sectors. In this work, recycled tire rubber aggregates and acoustically effective fractal cavities were combined in the design, modeling, and characterization of lightweight concrete hollow bricks. Fractal cavities improve the mechanical strength of the brick, its structural efficiency, and noise damping. The use of waste rubber as a total concrete aggregate represents an eco-friendlier solution than ordinary cementitious mix, providing, at the same time, enhanced lightweight properties, mechanical ductility, and better sound attenuation. The near compliance of rubberized blocks with technical requirements demonstrated good potential for incorporating waste rubber as aggregate for non-structural applications. View this paper
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15 pages, 5799 KiB  
Article
Mechanical Characterization and Finite Element Analysis of Hierarchical Sandwich Structures with PLA 3D-Printed Core and Composite Maize Starch Biodegradable Skins
by Maria Zoumaki, Michel T. Mansour, Konstantinos Tsongas, Dimitrios Tzetzis and Gabriel Mansour
J. Compos. Sci. 2022, 6(4), 118; https://doi.org/10.3390/jcs6040118 - 15 Apr 2022
Cited by 19 | Viewed by 3235
Abstract
The objective of this research is the fabrication of biodegradable starch-based sandwich materials. The investigated sandwich structures consist of maize starch-based films as skins and biodegradable 3D-printed polylactic filaments (PLA) as the core. To investigate the tensile properties of the skins, conventional and [...] Read more.
The objective of this research is the fabrication of biodegradable starch-based sandwich materials. The investigated sandwich structures consist of maize starch-based films as skins and biodegradable 3D-printed polylactic filaments (PLA) as the core. To investigate the tensile properties of the skins, conventional and nanocomposite films were prepared by a solution mixing procedure with maize starch and glycerol as the plasticizer, and they were reinforced with sodium montmorillonite clay, cellulose fibers and fiberglass fabric, with different combinations. Test results indicated a significant improvement in the mechanical and morphological properties of composite films prepared with sodium montmorillonite clay in addition with cellulose fibers and fiberglass fabric, with 20 wt% of glycerol. The morphology of the skins was also examined by scanning electron microscopy (SEM). Three orders of hierarchical honeycombs were designed for the 3D-printed core. To investigate how the skin material and the design of the core affect the mechanical properties of the starch-based sandwich, specimens were tested under a three-point bending regime. The test results have shown that the flexural strength of the biodegradable sandwich structure increased with the use of a second order hierarchy core and starch-based skins improved the strength and stiffness of the neat PLA-based honeycomb core. The bending behavior of the hierarchical honeycombs was also assessed with finite element analysis (FEA) in combination with experimental findings. Flexural properties demonstrated that the use of starch-based films and a PLA honeycomb core is a suitable solution for biodegradable sandwich structures. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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11 pages, 1133 KiB  
Article
Thermal Decomposition Characteristics of PEO/LiBF4/LAGP Composite Electrolytes
by Jacob Denney and Hong Huang
J. Compos. Sci. 2022, 6(4), 117; https://doi.org/10.3390/jcs6040117 - 14 Apr 2022
Cited by 6 | Viewed by 2994
Abstract
Lithium-based batteries with improved safety performance are highly desired. At present, most safety hazard is the consequence of the ignition and flammability of organic liquid electrolytes. Dry ceramic-polymer composite electrolytes are attractive for their merits of non-flammability, reduced gas release, and thermal stability, [...] Read more.
Lithium-based batteries with improved safety performance are highly desired. At present, most safety hazard is the consequence of the ignition and flammability of organic liquid electrolytes. Dry ceramic-polymer composite electrolytes are attractive for their merits of non-flammability, reduced gas release, and thermal stability, in addition to their mechanical strength and flexibility. We recently fabricated free-standing solid composite electrolytes made up of polyethylene oxide (PEO), LiBF4 salt, and Li1+xAlxGe2−x(PO4)3 (LAGP). This study is focused on analyzing the impacts of LAGP on the thermal decomposition characteristics in the series of PEO/LiBF4/LAGP composite membranes. It is found that the appropriate amount of LAGP can (1) significantly reduce the organic solvent trapped in the polymer network and (2) increase the peak temperature corresponding to the thermal degradation of the PEO/LiBF4 complex. In the presence of LAGP, although the peak temperature related to the degradation of free PEO is reduced, the portion of free PEO, as well as its decomposition rate, is effectively reduced, resulting in slower gas release. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume II)
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30 pages, 7826 KiB  
Article
FE Modelling and Simulation of the Size Effect of RC T-Beams Strengthened in Shear with Externally Bonded FRP Fabrics
by Amirali Abbasi, Zine El Abidine Benzeguir, Omar Chaallal and Georges El-Saikaly
J. Compos. Sci. 2022, 6(4), 116; https://doi.org/10.3390/jcs6040116 - 12 Apr 2022
Cited by 9 | Viewed by 2942
Abstract
The objective of this study is to conduct a finite-element (FE) numerical study to assess the effect of size on the shear resistance of reinforced concrete (RC) beams strengthened in shear with externally bonded carbon fibre-reinforced polymer (EB-CFRP). Although a few experimental studies [...] Read more.
The objective of this study is to conduct a finite-element (FE) numerical study to assess the effect of size on the shear resistance of reinforced concrete (RC) beams strengthened in shear with externally bonded carbon fibre-reinforced polymer (EB-CFRP). Although a few experimental studies have been done, there is still a lack of FE studies that consider the size effect. Experimental tests are time-consuming and costly and cannot capture all the complex and interacting parameters. In recent years, advanced numerical models and constitutive laws have been developed to predict the response of laboratory tests, particularly for issues related to shear resistance of RC beams, namely, the brittle response of concrete in shear and the failure modes of the interface layer between concrete and EB-CFRP (debonding and delamination). Numerical models have progressed in recent years and can now capture the interfacial shear stress along the bond and the strain profile along the fibres and the normalized main diagonal shear cracks. This paper presents the results of a nonlinear FE numerical study on nine RC beams strengthened in shear using EB-CFRP composites that were tested in the laboratory under three series, each containing three sizes of geometrically similar RC beams (small, medium, and large). The results reveal that numerical studies can predict experimental results with good accuracy. They also confirm that the shear strength of concrete and the contribution of CFRP to shear resistance decrease as the size of beams increases. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume II)
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14 pages, 2371 KiB  
Article
Patent Blue V Dye Adsorption by Fresh and Calcined Zn/Al LDH: Effect of Process Parameters and Experimental Design Optimization
by Aicha Machrouhi, Nawal Taoufik, Alaâeddine Elhalil, Hanane Tounsadi, Zakia Rais and Noureddine Barka
J. Compos. Sci. 2022, 6(4), 115; https://doi.org/10.3390/jcs6040115 - 11 Apr 2022
Cited by 17 | Viewed by 2562
Abstract
This work focuses on the adsorptive removal of patent blue V (PBV) dye from aqueous solution by Zn/Al layered double hydroxide in fresh (LDH) and calcined (CLDH) forms. The material was synthesized via coprecipitation and samples were characterized by XRD, FTIR and TGA-DTA. [...] Read more.
This work focuses on the adsorptive removal of patent blue V (PBV) dye from aqueous solution by Zn/Al layered double hydroxide in fresh (LDH) and calcined (CLDH) forms. The material was synthesized via coprecipitation and samples were characterized by XRD, FTIR and TGA-DTA. Dye retention was evaluated under different experimental conditions of contact time, pH, adsorbent dosage, temperature and initial dye concentration. Experimental results show that highest adsorption capacity occurred at acidic medium. Kinetics data were properly fitted with the pseudo-second-order model. Equilibrium data were best correlated to Langmuir model with maximum monolayer adsorption capacities of 185.40 and 344.37 mg/g, respectively, for LDH and CLDH. The process was endothermic and spontaneous in nature. Based on the preliminary study, full factorial experimental design (24) was used for the optimization of the effect of solution pH, adsorbent dose, initial dye concentration and the calcination. Thus, the optimal conditions to reach high equilibrium adsorption capacity were achieved at pH of 5, adsorbent dosage of 0.1 g/L, and initial dye concentration of 15 mg/L by CLDH. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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9 pages, 4082 KiB  
Article
Nano-Treating Promoted Natural Aging Al-Zn-Mg-Cu Alloys
by Jie Yuan, Qian Liu, Shuaihang Pan, Mingjie Xu, Narayanan Murali, Jiaxing Li, Shuai Wang and Xiaochun Li
J. Compos. Sci. 2022, 6(4), 114; https://doi.org/10.3390/jcs6040114 - 11 Apr 2022
Cited by 5 | Viewed by 2216
Abstract
Natural aging reduces the cost of alloy manufacturing while saving input energy but takes too long to complete for most Al-Zn-Mg-Cu alloys. Research has proved that nano-treating can facilitate precipitation in heat-treatable alloys. In this study, nano-treated Al-6.0Zn-2.6Mg-xCu samples containing different Cu contents [...] Read more.
Natural aging reduces the cost of alloy manufacturing while saving input energy but takes too long to complete for most Al-Zn-Mg-Cu alloys. Research has proved that nano-treating can facilitate precipitation in heat-treatable alloys. In this study, nano-treated Al-6.0Zn-2.6Mg-xCu samples containing different Cu contents were fabricated to investigate the influence of nano-treating on natural aging. TiC nanoparticles were used for nano-treating. Three cooling conditions after solution treatment (water quenching, air cooling, and as-cast) were investigated to check their quench sensitivities. The study shows the alloy’s microstructure was modified by nano-treating, and the growth of dendritic arms was inhibited. Compared to the control samples, nano-treating also increased both the microhardness and tensile strength of the alloy after natural aging. Out of the three different solution treatments, the air-cooled samples presented the highest UTS and microhardness values. The precipitation process was sped up by nano-treating by approximately 50%, and a higher volume fraction of GPII zones were formed in the nano-treated samples. HRTEM results also confirm the formation of more GPI and GPII zones in a nano-treated samples. With the help of natural aging, the Al-6.0Zn-2.6Mg-0.5Cu alloy reached a UTS of 455.7 ± 40.2 MPa and elongation of 4.52 ± 1.34% which makes it a great candidate for a naturally aged Al-Zn-Mg-Cu alloy. Full article
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13 pages, 2234 KiB  
Article
A Ternary Model for Particle Packing Optimization
by Taher M. Abu-Lebdeh, Ransford Damptey, Liviu Marian Ungureanu and Florian Ion Tiberiu Petrescu
J. Compos. Sci. 2022, 6(4), 113; https://doi.org/10.3390/jcs6040113 - 10 Apr 2022
Cited by 10 | Viewed by 5866
Abstract
Powder packing in metal powders is an important aspect of additive manufacturing (otherwise known as 3-D printing), as it directly impacts the physical and mechanical properties of materials. Improving the packing density of powder directly impacts the microstructure of the finished 3D-printed part [...] Read more.
Powder packing in metal powders is an important aspect of additive manufacturing (otherwise known as 3-D printing), as it directly impacts the physical and mechanical properties of materials. Improving the packing density of powder directly impacts the microstructure of the finished 3D-printed part and ultimately enhances the surface finish. To obtain the most efficient packing of a given powder, different powder blends of that material must be mixed to minimize the number of voids, irrespective of the irregularities in the particle morphology and flowability, thereby increasing the density of the powder. To achieve this, a methodology for mixing powder must be developed, for each powder type, to obtain the maximum packing density. This paper presents a model that adequately predicts the volumetric fraction of the powder grades necessary for obtaining the maximum packing density for a given powder sample. The model factors in the disparity between theoretical assumptions and the experimental outcome by introducing a volume reduction factor. We outline the model development steps in this paper, testing it with a real-world powder system. Full article
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18 pages, 4804 KiB  
Article
Poly(Lactic Acid) (PLA)-Based Nanocomposites: Impact of Vermiculite, Silver, and Graphene Oxide on Thermal Stability, Isothermal Crystallization, and Local Mechanical Behavior
by Sabrine Khammassi, Mostapha Tarfaoui, Kateřina Škrlová, Dagmar Měřínská, Daniela Plachá and Fouad Erchiqui
J. Compos. Sci. 2022, 6(4), 112; https://doi.org/10.3390/jcs6040112 - 8 Apr 2022
Cited by 18 | Viewed by 4600
Abstract
The structural, thermal, and mechanical properties of unreinforced and reinforced polylactic acid (PLA) were investigated. The PLA was a biopolymer that was reinforced with four fillers (i.e., graphene oxide (GO) and silver (Ag); vermiculite (VMT) and silver (Ag); and two organically modified vermiculites). [...] Read more.
The structural, thermal, and mechanical properties of unreinforced and reinforced polylactic acid (PLA) were investigated. The PLA was a biopolymer that was reinforced with four fillers (i.e., graphene oxide (GO) and silver (Ag); vermiculite (VMT) and silver (Ag); and two organically modified vermiculites). The processing technique for the production of the composite materials were carefully planned. The PLA nanocomposites were investigated by examining their morphological aspects, changes in PLA phases and transitions and, most importantly, the effect on certain final properties. X-ray diffraction and differential scanning calorimetry (DSC) analysis indicated that the sample was completely amorphous. Thermogravimetric analysis (TGA) results indicated that the presence of reinforcing particles in the PLA matrix did not affect the thermal degradation of these composites. Furthermore, the local mechanical properties were investigated using the microindentation method to evaluate the effect of different nanofillers. Scanning electron microscopy (SEM) and a VHX-500 optical digital microscope (Keyence International, Mechelen, Belgium) were also used to examine the surface morphology of the PLA polymer composites. These results can help to select suitable fillers to enhance the PLA performance of biopolymers. Full article
(This article belongs to the Special Issue Composite Materials for Environmental Applications)
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10 pages, 4363 KiB  
Article
Synthesis of TiB2/TiC/Al2O3 and ZrB2/ZrC/Al2O3 Composites by Low-Exotherm Thermitic Combustion with PTFE Activation
by Chun-Liang Yeh and Kuan-Ting Liu
J. Compos. Sci. 2022, 6(4), 111; https://doi.org/10.3390/jcs6040111 - 7 Apr 2022
Cited by 4 | Viewed by 2094
Abstract
TiB2–TiC–Al2O3 and ZrB2–ZrC–Al2O3 composites were produced via PTFE (polytetrafluoroethene)-activated combustion synthesis involving low-exotherm thermites. The reactant stoichiometries were 3TiO2 + 4Al + 0.5B4C + (1 − x)C + xCPTFE [...] Read more.
TiB2–TiC–Al2O3 and ZrB2–ZrC–Al2O3 composites were produced via PTFE (polytetrafluoroethene)-activated combustion synthesis involving low-exotherm thermites. The reactant stoichiometries were 3TiO2 + 4Al + 0.5B4C + (1 − x)C + xCPTFE and 3ZrO2 + 4Al + 0.5B4C + (1 − y)C + yCPTFE. PTFE played a dual role in promoting the reaction and carburizing reduced Ti and Zr. The threshold amount of PTFE for the TiO2/Al-based reaction was 2 wt% (i.e., x = 0.15) and for the ZrO2/Al-based reaction was 3 wt% (i.e., y = 0.25). The increase in PTFE increased the combustion front velocity and reaction temperature. The TiO2/Al-based reaction was more exothermic than the ZrO2/Al-based reaction and exhibited a faster combustion front and a lower activation energy. The TiB2–TiC–Al2O3 composite was produced with the minimum amount of PTFE at x = 0.15. The formation of ZrB2–ZrC–Al2O3 composites required more PTFE at y = 0.5 to improve the reduction of ZrO2. Both triplex composites displayed mixed microstructures consisting of short-rod borides, fine spherical carbides, and Al2O3 agglomerates. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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7 pages, 1609 KiB  
Article
Ion Beam Effect on the Structural and Optical Properties of AlN:Er
by Asmat Ullah, Muhammad Usman, Ahmer Hussain Shah, Altaf Hussain Shar and Muhammad Maqbool
J. Compos. Sci. 2022, 6(4), 110; https://doi.org/10.3390/jcs6040110 - 7 Apr 2022
Viewed by 2195
Abstract
Erbium (Er)-doped Aluminum Nitride (AlN) thin films were deposited and fabricated on Si (100) and Si (111) substrates in a Nitrogen atmosphere using the plasma magnetron sputtering technique. The deposited and fabricated thin films were thermally annealed at 900 °C in Argon (Ar) [...] Read more.
Erbium (Er)-doped Aluminum Nitride (AlN) thin films were deposited and fabricated on Si (100) and Si (111) substrates in a Nitrogen atmosphere using the plasma magnetron sputtering technique. The deposited and fabricated thin films were thermally annealed at 900 °C in Argon (Ar) atmosphere. The samples were irradiated with protons at a dose of 1 × 1014 ions/cm2 which carried an incident energy of 335 keV, using a tandem pelletron accelerator. Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD) were used for the stoichiometric and structural analysis of the films, while Fourier transforms infrared spectroscopy (FTIR) was performed to track the changes in the optical characteristics of thin films before and after the ions’ irradiation and implantation. The irradiation has affected the optical and structural properties of the films, which could be exploited to use the AlN:Er films for various optoelectronic and solid-state device applications. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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27 pages, 3531 KiB  
Review
Irradiation Effects in Polymer Composites for Their Conversion into Hybrids
by Traian Zaharescu and Marius Mariş
J. Compos. Sci. 2022, 6(4), 109; https://doi.org/10.3390/jcs6040109 - 6 Apr 2022
Cited by 8 | Viewed by 2728
Abstract
In this paper several aspects of profound modifications caused by high energy exposures are presented as possible candidates for the efficient adjusting processing of polymer materials. The class of hybrid composites receives special attention due to the large spectrum of formulations, where the [...] Read more.
In this paper several aspects of profound modifications caused by high energy exposures are presented as possible candidates for the efficient adjusting processing of polymer materials. The class of hybrid composites receives special attention due to the large spectrum of formulations, where the interphase interaction decisively influences the material properties. They represent potential start points for the intimate uniformity of hybrid morphologies. Their radiation processing turns composites onto hybrid morphology with expected features, because the transferred energy is spent for the modification of components and for their compatibility. The essential changes achieved in radiation processed composites explain the new material behavior and durability based on the peculiar restructuring of polymer molecules that occurred in the polymer phase. During high energy irradiation, the interaction between intermediates born in the constitutive phases may convert the primary composites into hybrids, integrating them into large applicability spheres. During the radiation exposure, the resulting hybrids gain a continuous dispersion by means of new chemical bonds. This type of compounds achieves some specific structural modifications in the polymer phase, becoming stable hybrid composites. The functional properties of hybrids definitely influence the material behavior due to the molecular changes based on the structural reasons. The radiolysis of the vulnerable component becomes an appropriate opportunity for the creation of new material with improved stability. The radiation treatment is a proper conversion procedure by which common mixtures may become continuously reorganized. This review presents several examples for the radiation modifications induced by radiation exposure that allow the compatibilization and binding of components as well as the creation of new structures with improved properties. This approach provides the reference patterns for the extension of radiation processing over the well-conducted adjustments of polymer composites, when certain material features are compulsorily required. From this review, several solutions for the adjustment of regular polymer composites into hybrid systems may become conceivable by the extended radiation processing. Full article
(This article belongs to the Special Issue Radiation Effects in Polymer Hybrids)
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9 pages, 1536 KiB  
Article
Solar-Light-Driven Ag9(SiO4)2NO3 for Efficient Photocatalytic Bactericidal Performance
by Malaa M. Taki, Rahman I. Mahdi, Amar Al-Keisy, Mohammed Alsultan, Nabil Janan Al-Bahnam, Wan Haliza Abd. Majid and Gerhard F. Swiegers
J. Compos. Sci. 2022, 6(4), 108; https://doi.org/10.3390/jcs6040108 - 6 Apr 2022
Cited by 1 | Viewed by 2443
Abstract
Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and [...] Read more.
Photocatalytic materials are being investigated as effective bactericides due to their superior ability to inactivate a broad range of dangerous microbes. In this study, the following two types of bacteria were employed for bactericidal purposes: Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The shape, crystal structure, element percentage, and optical properties of Ag9(SiO4)2NO3 were examined after it was successfully synthesized by a standard mixing and grinding processing route. Bactericidal efficiency was recorded at 100% by the following two types of light sources: solar and simulated light, with initial photocatalyst concentration of 2 µg/mL, and 97% and 95% of bactericidal activity in ultra-low photocatalyst concentration of 0.2 µg/mL by solar and simulated light, respectively, after 10 min. The survival rate was studied for 6 min, resulting in 99.8% inhibition at the photocatalyst dose of 2 µg/mL. The mechanism of bactericidal efficiency was found to be that the photocatalyst has high oxidation potential in the valence band. Consequently, holes play a significant part in bactericidal efficiency. Full article
(This article belongs to the Special Issue Metal Composites)
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24 pages, 7917 KiB  
Article
Finite Element Multi-Physics Analysis and Experimental Testing for Hollow Brick Solutions with Lightweight and Eco-Sustainable Cement Mix
by Matteo Sambucci, Abbas Sibai, Luciano Fattore, Riccardo Martufi, Sabrina Lucibello and Marco Valente
J. Compos. Sci. 2022, 6(4), 107; https://doi.org/10.3390/jcs6040107 - 5 Apr 2022
Cited by 9 | Viewed by 3102
Abstract
Combining eco-sustainability and technological efficiency is one of the “hot” topics in the current construction and architectural sectors. In this work, recycled tire rubber aggregates and acoustically effective fractal cavities were combined in the design, modeling, and experimental characterization of lightweight concrete hollow [...] Read more.
Combining eco-sustainability and technological efficiency is one of the “hot” topics in the current construction and architectural sectors. In this work, recycled tire rubber aggregates and acoustically effective fractal cavities were combined in the design, modeling, and experimental characterization of lightweight concrete hollow bricks. After analyzing the structural and acoustic behavior of the brick models by finite element analysis as a function of the type of constituent concrete material (reference and rubberized cement mixes) and hollow inner geometry (circular- and fractal-shaped hollow designs), compressive tests and sound-absorption measurements were experimentally performed to evaluate the real performance of the developed prototypes. Compared to the traditional circular hollow pattern, fractal cavities improve the mechanical strength of the brick, its structural efficiency (strength-to-weight ratio), and the medium–high frequency noise damping. The use of ground waste tire rubber as a total concrete aggregate represents an eco-friendlier solution than the ordinary cementitious mix design, providing, at the same time, enhanced lightweight properties, mechanical ductility, and better sound attenuation. The near-compliance of rubber-concrete blocks with standard requirements and the value-added properties have demonstrated a good potential for incorporating waste rubber as aggregate for non-structural applications. Full article
(This article belongs to the Special Issue Sustainable Composite Construction Materials)
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24 pages, 14545 KiB  
Article
The Impact of Fiber Orientation on Structural Dynamics of Short-Fiber Reinforced, Thermoplastic Components—A Comparison of Simulative and Experimental Investigations
by Alexander Kriwet and Markus Stommel
J. Compos. Sci. 2022, 6(4), 106; https://doi.org/10.3390/jcs6040106 - 1 Apr 2022
Cited by 4 | Viewed by 2708
Abstract
The quality of the fiber orientation of injection molding simulations and the transferred fiber orientation content, due to the process–structure coupling, influence the material modeling and thus the prediction of subsequently performed structural dynamics simulations of short-fiber reinforced, thermoplastic components. Existing investigations assume [...] Read more.
The quality of the fiber orientation of injection molding simulations and the transferred fiber orientation content, due to the process–structure coupling, influence the material modeling and thus the prediction of subsequently performed structural dynamics simulations of short-fiber reinforced, thermoplastic components. Existing investigations assume a reliable prediction of the fiber orientation in the injection molding simulation. The influence of the fiber orientation models and used boundary conditions of the process–structure coupling is mainly not investigated. In this research, the influence of the fiber orientation from injection molding simulations on the resulting structural dynamics simulation of short-fiber reinforced thermoplastic components is investigated. The Advani–Tucker Equation with phenomenological coefficient tensor is used in a 3- and 2.5-dimensional modeling approach for calculating the fiber orientation. The prediction quality of the simulative fiber orientations is evaluated in comparison to experiments. Depending on the material modeling and validation level, the prediction of the simulated fiber orientation differs in the range between 7.3 and 347.2% averaged deviation significantly. Furthermore, depending on the process–structure coupling and the number of layers over the thickness of the model, the Kullback–Leibner divergence differs in a range between 0.1 and 4.9%. In this context, more layers lead to higher fiber orientation content in the model and improved prediction of the structural dynamics simulation. This is significant for local and slightly for global structural dynamics phenomena regarding the mode shapes and frequency response behavior of simulative and experimental investigations. The investigations prove that the influence of the fiber orientation on the structural dynamics simulation is lower than the influence of the material modeling. With a relative average deviation of 2.8% in the frequency and 38.0% in the amplitude of the frequency response function, it can be proven that high deviations between experimental and simulative fiber orientations can lead to a sufficient prediction of the structural dynamics simulation. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume II)
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6 pages, 988 KiB  
Article
Cold Water Immersion Pretreatment of Post-Consuming Particleboards for Wood Chips Recovery by the Hydromechanical Process
by Foti Dafni, Sotirios Karastergiou and Antonios N. Papadopoulos
J. Compos. Sci. 2022, 6(4), 105; https://doi.org/10.3390/jcs6040105 - 31 Mar 2022
Viewed by 1951
Abstract
In this research work, the effect of 20-day immersion of various types of reclaimed particleboards on thickness swelling and water absorption is investigated. This simple procedure has been chosen as the pretreatment to facilitate the chips’ recovery by the hydromechanical (water jet) method. [...] Read more.
In this research work, the effect of 20-day immersion of various types of reclaimed particleboards on thickness swelling and water absorption is investigated. This simple procedure has been chosen as the pretreatment to facilitate the chips’ recovery by the hydromechanical (water jet) method. Maximum swelling was achieved after 20-day immersion but the differences between 10 and 20-day immersion were small, indicating that the time of 10-day immersion can be chosen as the pretreatment time. It was found that the bond between wood chips’ particles was not completely failed since the permanent swelling after immersion and drying was lower than the maximum swelling. Hence, the proposed method needs to be improved by increasing the cross-section areas of particleboard samples after their breaking in order to create irregular pieces and facilitate the water action against the bond of wood particles. Full article
(This article belongs to the Special Issue Wood-Polymer Composites)
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11 pages, 6487 KiB  
Article
Poly(ethyl methacrylate) Composite Coatings Containing Halogen-Free Inorganic Additives with Flame-Retardant Properties
by Xinqian Liu, Stephen Veldhuis, Ritch Mathews and Igor Zhitomirsky
J. Compos. Sci. 2022, 6(4), 104; https://doi.org/10.3390/jcs6040104 - 28 Mar 2022
Cited by 1 | Viewed by 2299
Abstract
This investigation is motivated by the need for the development of polymer coatings containing inorganic flame-retardant materials (FRMs) and the replacement of toxic halogenated FRMs. A green strategy is reported for the fabrication of poly(ethyl methacrylate) (PEMA)-FRM composite coatings using a dip-coating method. [...] Read more.
This investigation is motivated by the need for the development of polymer coatings containing inorganic flame-retardant materials (FRMs) and the replacement of toxic halogenated FRMs. A green strategy is reported for the fabrication of poly(ethyl methacrylate) (PEMA)-FRM composite coatings using a dip-coating method. The use of water-isopropanol co-solvent allows the replacement of regular toxic solvents for PEMA. The abilities to form concentrated solutions of high-molecular-mass PEMA and to disperse FRM particles in such solutions are the main factors in the fabrication of coatings using a dip-coating technique. Huntite, halloysite, and hydrotalcite are used as advanced FRMs for the fabrication of PEMA-FRM coatings. FTIR, XRD, SEM, and TGA data are used for the analysis of the microstructure and composition of PEMA-FRM coatings. PEMA and PEMA-FRM coatings provide corrosion protection of stainless steel. The ability to form laminates with different layers using a dip-coating method facilitates the fabrication of composite coatings with enhanced properties. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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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 12 | Viewed by 4151
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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13 pages, 6273 KiB  
Article
Effects of Wetting and Drying Cycles on Microstructure Change and Mechanical Properties of Coconut Fibre-Reinforced Mortar
by Huyen Bui, Daniel Levacher, Mohamed Boutouil and Nassim Sebaibi
J. Compos. Sci. 2022, 6(4), 102; https://doi.org/10.3390/jcs6040102 - 25 Mar 2022
Cited by 7 | Viewed by 2605
Abstract
Natural fibre-reinforced cementitious composites are commonly used as outer construction materials. They usually suffer weather as a result of being expose to various types of climates. In this study, a series of experimental tests were carried out to investigate the deterioration mechanism and [...] Read more.
Natural fibre-reinforced cementitious composites are commonly used as outer construction materials. They usually suffer weather as a result of being expose to various types of climates. In this study, a series of experimental tests were carried out to investigate the deterioration mechanism and mechanical properties of mortars incorporating coconut fibres due to repeated wetting and drying. The results indicated that although the compressive strength was found to increase after the first cycle, both compressive and flexural strengths underwent a significant decrease in the fifth cycle. In addition, at high temperatures, mortar matrixes retain their stable structure, according to the results of TGA analysis. When wetting and drying curing was applied, there was a significant degradation of fibres in the mortar. Full article
(This article belongs to the Special Issue Feature Papers in Journal of Composites Science in 2022)
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18 pages, 6203 KiB  
Article
Derivation and Validation of Linear Elastic Orthotropic Material Properties for Short Fibre Reinforced FLM Parts
by Christian Witzgall, Harald Völkl and Sandro Wartzack
J. Compos. Sci. 2022, 6(4), 101; https://doi.org/10.3390/jcs6040101 - 22 Mar 2022
Cited by 2 | Viewed by 3283
Abstract
Additively manufactured parts play an increasingly important role in structural applications. Fused Layer Modeling (FLM) has gained popularity due to its cost-efficiency and broad choice of materials, among them, short fibre reinforced filaments with high specific stiffness and strength. To design functional FLM [...] Read more.
Additively manufactured parts play an increasingly important role in structural applications. Fused Layer Modeling (FLM) has gained popularity due to its cost-efficiency and broad choice of materials, among them, short fibre reinforced filaments with high specific stiffness and strength. To design functional FLM parts, adequate material models for simulations are crucial, as these allow for reliable simulation within virtual product development. In this contribution, a new approach to derive FLM material models for short fibre reinforced parts is presented; it is based on simultaneous fitting of the nine orthotropic constants of a linear elastic material model using six specifically conceived tensile specimen geometries with varying build direction and different extrusion path patterns. The approach is applied to a 15 wt.% short carbon-fibre reinforced PETG filament with own experiments, conducted on a Zwick HTM 5020 servo-hydraulic high-speed testing machine. For validation, the displacement behavior of a geometrically more intricate demonstrator part, printed upright, under bending is predicted using simulation and compared to experimental data. The workflow proves stable and functional in calibration and validation. Open research questions are outlined. Full article
(This article belongs to the Special Issue Characterization and Modelling of Composites, Volume II)
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12 pages, 3924 KiB  
Article
Comparison of Experimental and Calculated Tensile Properties of Flax Fibres
by Niphaphun Soatthiyanon, Alan Crosky and Michael T. Heitzmann
J. Compos. Sci. 2022, 6(4), 100; https://doi.org/10.3390/jcs6040100 - 22 Mar 2022
Cited by 6 | Viewed by 2814
Abstract
The tensile properties of natural plant fibres are commonly determined by single fibre testing. The cross-sectional area used to determine the modulus and strength is usually obtained by measuring the fibre width and using this as the fibre diameter on the assumption that [...] Read more.
The tensile properties of natural plant fibres are commonly determined by single fibre testing. The cross-sectional area used to determine the modulus and strength is usually obtained by measuring the fibre width and using this as the fibre diameter on the assumption that the fibres are circular in section. The assumption of circularity is reasonably true for synthetic fibres but is not correct for natural fibres, and this can lead to a substantial error when determining the tensile properties of the fibres. The incorporation of a fibre area correction factor, which takes into account the non-circularity of natural fibres, has been proposed by earlier workers, who used it successfully to predict the mechanical properties of jute fibre composites. The aim of the present study was to evaluate the wider applicability of this methodology by applying it to flax fibre composites. The work involved determination of the tensile properties of 113 flax technical fibres using an experimentally determined fibre area correction factor to account for the non-circularity of the fibres. The data were then compared with those obtained from back-calculation of the results obtained from longitudinal tensile testing of flax/vinyl ester unidirectional composites manufactured utilising identical fibres to those used in the single fibre tests. Account was taken of the effect of fibre length on strength. The experimentally determined fibre area correction factor was found to be 2.70. Taking this into account for the single fibre tests, the back-calculated modulus of the flax fibres was within 6% of that obtained from the single fibre tests, while the strength was within 7%. Full article
(This article belongs to the Special Issue Polymeric Composites Reinforced with Natural Fibers and Nanofillers)
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