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2. A Study of Some Mechanical Properties of Composite Materials with a Dammar-Based Hybrid Matrix and Reinforced by Waste Paper
- Author
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Marius Marinel Stănescu and Dumitru Bolcu
- Subjects
hybrid resin ,waste paper ,composite materials ,mechanical properties ,chemical structure ,Organic chemistry ,QD241-441 - Abstract
When obtaining environment-friendly hybrid resins made of a blend of Dammar natural resin, in a prevailing volume ratio, with epoxy resin, it is challenging to find alternatives for synthetic resins. Composite materials reinforced with waste paper and matrix made of epoxy resin or hybrid resin with a volume ratio of 60%, 70% and 80% Dammar were studied. All samples obtained have been submitted to tensile tests and Scanning Electron Microscopy (SEM) analysis. The tensile response, tensile strength, modulus of elasticity, elongation at break and the analysis of the fracture surface were determined. The damping properties of vibrations of bars in hybrid resins and in the composite materials under study were also examined. The mechanical properties of the four types of resins and of the composite materials were compared. The chemical composition for a hybrid resin specimen were obtained using the Fourier Transformed Infrared Spectroscopy (FTIR) and Energy, Dispersive X-ray Spectrometry (EDS) analyzes.
- Published
- 2020
- Full Text
- View/download PDF
3. Abstracts of contributed papers
- Published
- 1994
4. A Preliminary Study on Paper Sheets Based Epoxy Composites Designed for Repairing Work Application and Its Properties -- A Review.
- Author
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Hussin, Muhamad Hellmy
- Subjects
EPOXY resins ,COMPOSITE materials ,MECHANICAL behavior of materials ,SCANNING electron microscopy ,MICROSTRUCTURE - Abstract
This is a review of studies on various types of paper-based epoxy composites currently being designed and developed for technological use. The concept of designing composite materials is very significant for small to large industry and it is important where initiation of repairing work is now being considered for engineering applications. This composite material is of interest due to its advantages compared with others, including low environmental effects and low cost for a wide range of works. This review aims to provide an overview of morphological, physical and mechanical properties of various paper sheetsbased epoxy composites and details of achievements made. From this approach, this paper also presents the preliminary study of SEM results of paper sheets-based epoxy composites designed for repairing work applications. It has been found that a well-arranged laminated paper sheet layers could help the bond strength with epoxy matrix. Thus, this paper sheet-based epoxy composite can be considered as an easiest way, cheap and biodegradable that can be used for various small repairing works in structural and automotive applications. [ABSTRACT FROM AUTHOR]
- Published
- 2018
5. A Study of Some Mechanical Properties of Composite Materials with a Dammar-Based Hybrid Matrix and Reinforced by Waste Paper
- Author
-
Dumitru Bolcu and Marius Marinel Stănescu
- Subjects
Materials science ,hybrid resin ,Polymers and Plastics ,Synthetic resin ,Scanning electron microscope ,composite materials ,Infrared spectroscopy ,Young's modulus ,General Chemistry ,Epoxy ,mechanical properties ,Article ,lcsh:QD241-441 ,symbols.namesake ,Surface-area-to-volume ratio ,lcsh:Organic chemistry ,visual_art ,Ultimate tensile strength ,symbols ,visual_art.visual_art_medium ,chemical structure ,waste paper ,Fourier transform infrared spectroscopy ,Composite material - Abstract
When obtaining environment-friendly hybrid resins made of a blend of Dammar natural resin, in a prevailing volume ratio, with epoxy resin, it is challenging to find alternatives for synthetic resins. Composite materials reinforced with waste paper and matrix made of epoxy resin or hybrid resin with a volume ratio of 60%, 70% and 80% Dammar were studied. All samples obtained have been submitted to tensile tests and Scanning Electron Microscopy (SEM) analysis. The tensile response, tensile strength, modulus of elasticity, elongation at break and the analysis of the fracture surface were determined. The damping properties of vibrations of bars in hybrid resins and in the composite materials under study were also examined. The mechanical properties of the four types of resins and of the composite materials were compared. The chemical composition for a hybrid resin specimen were obtained using the Fourier Transformed Infrared Spectroscopy (FTIR) and Energy, Dispersive X-ray Spectrometry (EDS) analyzes.
- Published
- 2020
6. Al2O3/Cu-O composites fabricated by pressureless infiltration of paper-derived Al2O3 porous preforms.
- Author
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Pfeiffer, Stefan, Lorenz, Hannes, Fu, Zongwen, Fey, Tobias, Greil, Peter, and Travitzky, Nahum
- Subjects
- *
ALUMINUM oxide , *COMPOSITE materials , *POROUS materials , *COPPER alloys , *FABRICATION (Manufacturing) - Abstract
Abstract Al 2 O 3 /Cu-O composites were fabricated from the paper-derived alumina matrix infiltrated with a Cu-3.2 wt% O alloy. Paper-derived alumina preforms with an open porosity ranging from ∼ 14 to ∼ 25 vol% were prepared by sintering of alumina-loaded preceramic papers at 1600 °C for 4 h. Pressureless infiltration at 1320 °C for 4 h of the preforms with Cu–O alloy resulted in the nearly dense materials with good mechanical and electrical properties, e.g. fracture toughness up to 6 MPa m0.5, four-point-bending strength up to 342 MPa, Young's modulus up to 281 GPa and electrical conductivity up to 2 MS/m depending on the volume fraction of copper alloy in the composites. The technological capability of this approach was demonstrated using prototypes in various engineering fields fabricated by lamination, corrugating and Laminated Object Manufacturing (LOM) methods. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
7. Multifunctional graphene oxide paper embodied structural dielectric capacitor based on carbon fibre reinforced composites.
- Author
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Chan, Kit-Ying, Lin, Han, Qiao, Kun, Jia, Baohua, and Lau, Kin-Tak
- Subjects
- *
GRAPHENE oxide , *CARBON fiber-reinforced plastics , *CAPACITORS , *COMPOSITE materials , *DIELECTRIC materials - Abstract
In this study, the multifunctionality of structural dielectric capacitor made by integrating graphene oxide paper into carbon fibre reinforced composite has been investigated. The study is based on an earlier work on the use of graphene oxide for dielectric material in the structural dielectric capacitor, in which electrical properties have been characterized. In this work, an in-depth study on electrical and mechanical properties of this kind of structural dielectric capacitor have been carried out. In addition, the multifunctional efficiency of structural dielectric capacitors were evaluated and compared with existing structural dielectric capacitors. Through experiments, it is revealed that both electrical and mechanical properties of the structural dielectric capacitors were significantly enhanced by interleaving a graphene oxide paper in the middle of composite. Therefore, the multifunctional efficiency of this kind of structural dielectric capacitors has been ultimately improved, indicating the excellent potential of graphene oxide paper in the development of multifunctional materials for energy storage, potentially for high-strength required applications, such as electric vehicles and unmanned aerial vehicles. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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8. Valorization of Kraft Lignin from Black Liquor in the Production of Composite Materials with Poly(caprolactone) and Natural Stone Groundwood Fibers.
- Author
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Tarrés, Quim, Aguado, Roberto, Domínguez-Robles, Juan, Larrañeta, Eneko, and Delgado-Aguilar, Marc
- Subjects
SULFATE waste liquor ,THERMOPLASTIC composites ,COMPOSITE materials ,PLASTICS ,LIGNINS ,PAPER pulp ,FIBERS - Abstract
The development of new materials is currently focused on replacing fossil-based plastics with sustainable materials. Obtaining new bioplastics that are biodegradable and of the greenest possible origin could be a great alternative for the future. However, there are some limitations—such as price, physical properties, and mechanical properties—of these bioplastics. In this sense, the present work aims to explore the potential of lignin present in black liquor from paper pulp production as the main component of a new plastic matrix. For this purpose, we have studied the simple recovery of this lignin using acid precipitation, its thermoplastification with glycerin as a plasticizing agent, the production of blends with poly(caprolactone) (PCL), and finally the development of biocomposite materials reinforcing the blend of thermoplastic lignin and PCL with stone groundwood fibers (SGW). The results obtained show that thermoplastic lignin alone cannot be used as a bioplastic. However, its combination with PCL provided a tensile strength of, e.g., 5.24 MPa in the case of a 50 wt.% blend. In addition, when studying the properties of the composite materials, it was found that the tensile strength of a blend with 20 wt.% PCL increased from 1.7 to 11.2 MPa with 40 wt.% SGW. Finally, it was proven that through these biocomposites it is possible to obtain a correct fiber–blend interface. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. Influence of Polymethylsilsesquioxane Content to the Thermal Stability of Meta-Aramid Fiber Insulation Paper.
- Author
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Zheng, Wei, Xie, Jufang, Zhang, Jingwen, Tang, Chao, and Zhao, Zhongyong
- Subjects
- *
THERMAL stability , *NANOPARTICLE synthesis , *COMPOSITE materials , *CHEMICAL bonds , *DIFFUSION bonding (Metals) - Abstract
Polymethylsilsesquioxane (PMSQ) nanoparticles with mass percentages of 0, 2.5, 5.0, 7.2, 9.4 wt %, respectively, were constructed by molecular dynamics methods in this paper. Composite molecular models were established using PMSQ and MPIA (poly-metaphenylene isophthalamide) fiber. The influence of different PMSQ contents on the thermal stability of meta-aramid insulation paper was analyzed from the parameters of mechanical property, interaction energy, and mean square displacement. The results showed that the trend of mechanical properties decreased with the increase of PMSQ content. When the PMSQ content was 2.5 wt %, the mechanical properties of the composited model were the best, which was about 24% higher than that of the unmodified model. From an intermolecular bonding and nonbonding point of view, the energy parameters of composite model with the 2.5 wt % content was better than those of the composite model with other contents. Therefore, it is considered that MPIA can interact better with the 2.5 wt % content PMSQ composite model. When the PMSQ content is 2.5 wt %, the overall chain movement in the composite model is slower than that of the unmodified model, which can effectively inhibit the diffusion movement of the MPIA chain. In general, the thermal stability of composite molecular models MPIA and PMSQ (2.5 wt %) was better improved. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
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10. Superheated Steam Treatment of Oil Palm Mesocarp Fiber Improved the Properties of Fiber-Polypropylene Biocomposite.
- Author
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Ahamad Nordin, Noor Ida Amalina, Ariffin, Hidayah, Hassan, Mohd Ali, Yoshihito Shirai, Yoshito Ando, Ibrahim, Nor Azowa, and Wan Md Zin Wan Yunus
- Subjects
SUPERHEATED steam ,OIL palm ,POLYPROPYLENE ,COMPOSITE materials ,MECHANICAL behavior of materials ,THERMAL properties - Abstract
The effect of fiber surface modification by superheated steam (SHS) treatment and fiber content (30 to 50 wt.%) was evaluated relative to the mechanical, morphology, thermal, and water absorption properties of oil palm mesocarp fiber (OPMF)/polypropylene (PP) biocomposites. SHS treatment of OPMF was conducted between 190 and 230 °C for 1 h, then the SHS-treated fiber was subjected to melt-blending with PP for biocomposite production. The biocomposite prepared from SHS-OPMF treated at 210 °C with 30 wt.% fiber loading resulted in SHS-OPMF/PP biocomposites with a tensile strength of 20.5 MPa, 25% higher than untreated-OPMF/PP biocomposites. A significant reduction of water absorption by 31% and an improved thermal stability by 8% at T
5%degradation were also recorded. Scanning electron microscopy images of fractured SHS-OPMF/PP biocomposites exhibited less fiber pull-out, indicating that SHS treatment improved interfacial adhesion between fiber and PP. The results demonstrated SHS treatment is an effective surface modification method for biocomposite production. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
11. An Experimental Study on the Performance of Materials for Repairing Cracks in Tunnel Linings under Erosive Environments.
- Author
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Zhang, Wenliang, Wang, Yufeng, Nan, Xiaocong, Sun, Shangqu, Ma, Yanhui, and Wu, Yankai
- Subjects
MECHANICAL behavior of materials ,TUNNEL lining ,EPOXY resins ,REQUIREMENTS engineering ,COMPOSITE materials - Abstract
Addressing the current lining cracking problem in coastal tunnels, this paper independently introduces a novel type of repair material for tunnel lining cracks—the composite repair material consisting of waterborne epoxy resin and ultrafine cement (referred to as EC composite repair material). Through indoor testing, we have analyzed the change rule of the mass change rate, compressive strength, flexural strength, and chloride ion concentration of the repair material samples in erosive environments, with the dosage of each component in the EC composite repair material being varied. We have also investigated the working performance, mechanical properties, and microstructure of the repair material. The results of this study show that when the proportion of each component of ultrafine cement, waterborne epoxy resin, waterborne epoxy curing agent, waterborne polyurethane, defoamer, and water is 100:50:50:2.5:0.5:30, the performance of the EC composite repair material in a chloride ion-rich environment is optimal in all aspects. When the mixing ratio of each component of the EC composite repair material is as stated above, the repair material exhibits the best performance in a chloride ion erosion environment. With this ratio of components in the EC composite repair material, the fluidity, setting time, compressive strength, flexural strength, and bond strength of the repair material in a chloride ion erosion environment can meet the requirements of relevant specifications, and it is highly effective in repairing tunnel lining cracks. The polymeric film formed by the reaction between the waterborne epoxy resin emulsion and the curing agent fills the pores between the hydration products, resulting in a densely packed internal structure of EC composite repair material with enhanced erosion resistance, making it very suitable for repairing cracks in tunnel linings in erosive environments. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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12. Improving the Mechanical Properties of Ultra-Low Density Plant Fiber Composite (ULD_PFC) by Refining Treatment.
- Author
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Tingjie Chen, Yongqun Xie, Qihua Wei, Wang, Xiaodong (Alice), Hagman, Olle, Karlsson, Olov, Jinghong Liu, and Ming Lin
- Subjects
PLANT mechanics ,PLANT fibers ,COMPOSITE materials ,WOOD-pulp refining ,HYDROGEN bonding - Abstract
To improve the mechanical properties of ultra-low density plant fiber composite (ULD_PFC), a suitable beating process to improve the fibrillation of cellulose fibers and maintain their length was investigated. The physical properties of cellulose fibers and papers, surface chemical bonds, and internal bond strength (IB) of ULD_PFCs were analyzed. The results showed that the beating degrees, degree of fibrillation, and fiber fines increased with the decreasing of beating gap, except for the fiber weight-average length, width, kink index, and curl index. The tensile index and burst index of paper showed an increasing trend with an increase in beating degree, while the tear index showed a decreasing trend. FTIR results showed that intermolecular and intramolecular hydrogen bonds in ULDF were broken. A suitable beating gap of 30 µm with a beating degree of 35 °SR was obtained. The corresponding IB was 50.9 kPa, which represented an increase of 73.1% over fibers with a beating degree of 13 °SR. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
13. Distinguishing contributions of ceramic matrix and binder metal to the plasticity of nanocrystalline cermets
- Author
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Xiaoyan Song, Xinru Ge, Wenwu Xu, Fawei Tang, Xuemei Liu, Hao Lu, Chao Hou, and Xiangfei Meng
- Subjects
plastic deformation ,computational modeling ,Materials science ,composite materials ,Nucleation ,materials modeling ,02 engineering and technology ,Plasticity ,mechanical properties ,Ceramic matrix composite ,01 natural sciences ,Biochemistry ,dislocation interactions ,0103 physical sciences ,nanostructures ,General Materials Science ,Composite material ,010302 applied physics ,Crystallography ,dynamical simulations ,nanocrystalline cermets ,General Chemistry ,Cermet ,molecular dynamics simulations ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Research Papers ,Nanocrystalline material ,QD901-999 ,Cemented carbide ,Deformation (engineering) ,Dislocation ,0210 nano-technology - Abstract
Contributions to plasticity from hard matrix and binder metal in nanocrystalline cermets were studied by molecular dynamics simulations., Using the typical WC–Co cemented carbide as an example, the interactions of dislocations within the ceramic matrix and the binder metal, as well as the possible cooperation and competition between the matrix and binder during deformation of the nanocrystalline cermets, were studied by molecular dynamics simulations. It was found that at the same level of strain, the dislocations in Co have more complex configurations in the cermet with higher Co content. With loading, the ratio between mobile and sessile dislocations in Co becomes stable earlier in the high-Co cermet. The strain threshold for the nucleation of dislocations in WC increases with Co content. At the later stage of deformation, the growth rate of WC dislocation density increases more rapidly in the cermet with lower Co content, which exhibits an opposite tendency compared with Co dislocation density. The relative contribution of Co and WC to the plasticity of the cermet varies in the deformation process. With a low Co content, the density of WC dislocations becomes higher than that of Co dislocations at larger strains, indicating that WC may contribute more than Co to the plasticity of the nanocrystalline cermet at the final deformation stage. The findings in the present work will be applicable to a large variety of ceramic–metal composite materials.
- Published
- 2020
14. Experimental Study on the Performance of Glass/Basalt Fiber Reinforced Concrete Unidirectional Plate under Impact Load.
- Author
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Li, Liancheng, Chen, Jueliang, Liu, Siyu, Huang, Xin, and Chen, Hui
- Subjects
FIBER-reinforced concrete ,BASALT ,IMPACT loads ,COMPOSITE materials ,FIBROUS composites ,REINFORCED concrete ,GLASS - Abstract
Fiber-reinforced composite materials have emerged as essential solutions for addressing the durability challenges of traditional reinforced concrete, owing to their lightweight nature, high strength, ease of construction, superior tensile capacity, robust corrosion resistance, and excellent electromagnetic insulation properties. This paper delves into the influence of loading rate and fiber bar type on the mechanical characteristics of concrete one-way plates through impact experiments on such plates fitted with glass/basalt fiber bars at varying drop weight heights. The test results reveal a direct correlation between increasing loading rates and escalating damage in fiber-reinforced concrete one-way plates, reflected in the progressive rise in peak deflection and residual displacement at the mid-span of the specimens. Notably, when subjected to higher impact loads, glass fiber-reinforced concrete specimens exhibit amplified deformation and intricate crack formations, consequently diminishing the overall deformation resistance of the plate. Furthermore, glass/basalt fiber-reinforced composites demonstrate notable vibration damping qualities, characterized by substantial residual displacement, minimal rebound, and rapid decay following vibration stimulation. Overall, glass fiber-reinforced one-way plates display marginally superior impact resistance compared to their basalt fiber-reinforced counterparts. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
15. Application of Ni/SiCw Composite Material in MEMS Microspring.
- Author
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Lai, Liyan, Yu, Guanliang, Wang, Guilian, Li, Yigui, Ding, Guifu, and Yang, Zhuoqing
- Subjects
LEAF springs ,SERVICE life ,HEAT treatment ,COMPOSITE coating ,MATERIAL plasticity ,COMPOSITE materials ,ADHESIVES - Abstract
The microspring is a typical type of device in MEMS devices, with a wide range of application scenarios and demands, among which a popular one is the microelectroformed nickel-based planar microspring prepared by the UV-LIGA technology based on the SU-8 adhesive. It is worth noting that the yield strength of the electrodeposited nickel microstructure is low, and the toughness of the structure is not high, which is unbeneficial for the enduring and stable operation of the spring. The paper mainly presents the methods of preparing high-aspect-ratio Ni/SiCw microstructures for MEMS devices based on UV-LIGA technology, developing Ni/SiCw-based microspring samples with a thickness of 300 μm, and applying a DMA tensile tester for mechanical property tests and characterization. In addition, the paper explores the influence of heat treatment at 300 °C and 600 °C on the tensile properties and microstructure of composite coatings. The results show that the W-form microspring prepared from Ni/SiCw composites not only has a wider linear range (about 1.2 times wider) than that of pure nickel material but also has a stronger resistance capacity to plastic deformation, which is competent for MEMS device applications in environments below 300 °C. The research provides a frame of reference and guidance for improving the stable cyclic operating life of such flat springs. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
16. Microstructure and Mechanical Properties of the EN AC-AlSi12CuNiMg Alloy and AlSi Composite Reinforced with SiC Particles.
- Author
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Sirata, G. G., Wacławiak, K., and Dolata, A. J.
- Subjects
MECHANICAL properties of metals ,ALUMINUM alloys ,SCANNING electron microscopes ,MODULUS of elasticity ,COMPOSITE materials - Abstract
There is growing interest in developing more advanced materials, as conventional materials are unable to meet the demands of the automotive, aerospace, and military industries. To meet the needs of these sectors, the use of advanced materials with superior properties, such as metal matrix composites, is essential. This paper discusses the evaluation of microstructural and mechanical properties of conventional eutectic EN AC-AlSi12CuNiMg aluminum alloy (AlSi12) and advanced composite based on EN AC-AlSi12CuNiMg alloy matrix with 10 wt% SiC particle reinforcement (AlSi12/10SiC
p ). The microstructure of these materials was investigated with the help of metallographic techniques, specifically using a light microscope (LM) and a scanning electron microscope (SEM). The results of the microstructural analysis show that the SiC particles are uniformly distributed in the matrix. The results of the mechanical tests indicate that the tensile properties and hardness of the AlSi12/10SiCp composite are significantly higher than those of the unreinforced eutectic alloy. For AlSi12/10SiCp composite, the tensile strength is 21% higher, the yield strength is 16% higher, the modulus of elasticity is 20% higher, and the hardness is 11% higher than unreinforced matrix alloy. However, the unreinforced AlSi12 alloy has a percentage elongation that is 16% higher than the composite material. This shows that the AlSi12/10SiCp composite has a lower ductility than the unreinforced AlSi12 alloy. The tensile specimens of the tested composite broke apart in a brittle manner with no discernible neck development, in contrast to the matrix specimens, which broke apart in a ductile manner with very little discernible neck formation. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
17. The Influence of the Modification of Carbon Nanotubes on the Properties of Copper Matrix Sintered Materials.
- Author
-
Piasecki, Adam, Sobkowiak, Julia, Boroński, Dariusz, Siwińska-Ciesielczyk, Katarzyna, and Paczos, Piotr
- Subjects
CARBON nanotubes ,STRAINS & stresses (Mechanics) ,VICKERS hardness ,HARDNESS testing ,TRANSMISSION electron microscopy ,COMPOSITE materials ,POWDER metallurgy - Abstract
This paper presents the results of research on the microstructure, mechanical, and tribological properties of Cu/0.5 wt.% MWCNT (multi-walled carbon nanotube) sintered composite materials produced by powder metallurgy. The purpose of this research was to investigate the impact of carbon nanotube modifications on the uniformity of their dispersion and the effectiveness of their bonding with the matrix. The MWCNTs were modified by chemical oxidation. Additionally, a modification of the ingredient mixing method utilizing ultrasonic frequencies was employed. The tests were carried out using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Vickers hardness tests, static compression tests, and wear tests using the pin-on-disc method. Furthermore, mechanical properties and strain distribution analyses of the micro-specimens were conducted using the Micro-Fatigue System (MFS). The implemented modifications had a positive effect on the dispersion of MWCNTs in the copper matrix and on the mechanical and tribological properties of the sinters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Study of the Effect of NaOH Treatment on the Properties of GF/VER Composites Using AE Technique.
- Author
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Ming, Lin, He, Haonan, Li, Xin, Tian, Wei, and Zhu, Chengyan
- Subjects
SHEAR strength ,FLEXURAL strength ,COMPOSITE materials ,ACOUSTIC emission ,DEBONDING - Abstract
The purpose of this study is to use acoustic emission (AE) technology to explore the changes in the interface and mechanical properties of GF/VER composite materials after being treated with NaOH and to analyze the optimal modification conditions and damage propagation process. The results showed that the GF surface became rougher, and the number of reactive groups increased after treating the GF with a NaOH solution. This treatment enhanced the interfacial adhesion between the GF and VER, which increased the interfacial shear strength by 25.31% for monofilament draw specimens and 27.48% for fiber bundle draw specimens compared to those before the GF was modified. When the modification conditions were a NaOH solution concentration of 2 mol/L and a treatment time of 48 h, the flexural strength of the GF/VER composites reached a peak value of 346.72 MPa, which was enhanced by 20.96% compared with before the GF was modified. The process of damage fracture can be classified into six types: matrix cracking, interface debonding, fiber pullout, fiber relaxation, matrix delamination, and fiber breakage, and the frequency ranges of these failure mechanisms are 0~100 kHz, 100~250 kHz, 250~380 kHz, 380~450 kHz, 450~600 kHz, and 600 kHz and above, respectively. This paper elucidates the fracture process of GF/VER composites in three-point bending. It establishes the relationship between the AE signal and the interfacial and force properties of GF/VER composites, realizing the classification of the damage process and characterizing the mechanism. The frequency ranges of damage types and failure mechanisms found in this study offer important guidance for the design and improvement of composite materials. These results are of great significance for enhancing the interfacial properties of composites, assessing the damage and fracture behaviors, and implementing health monitoring. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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19. Assessment Effect of Nanometer-Sized Al 2 O 3 Fillers in Polylactide on Fracture Probability of Filament and 3D Printed Samples by FDM.
- Author
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Smirnov, Anton, Peretyagin, Pavel, and Nikitin, Nikita
- Subjects
ALUMINUM oxide ,POLYLACTIC acid ,FUSED deposition modeling ,STYRENE-butadiene rubber ,ALUMINA composites ,ACRYLONITRILE butadiene styrene resins ,PARTICLE size distribution ,FIBERS - Abstract
In this paper, a mathematical model for the description of the failure probability of filament and fused deposition modeling (FDM)-printed products is considered. The model is based on the results of tensile tests of filament samples made of polyacrylonitrile butadiene styrene (ABS), polylactide (PLA), and composite PLA filled with alumina (Al
2 O3 ) as well after FDM-printed products of "spatula" type. The application of probabilistic methods of fracture analysis revealed that the main contribution to the reduction of fracture probability is made by the elastic and plastic stages of the fracture curve under static loading. Particle distribution analysis of Al2 O3 combined with fracture probability analysis shows that particle size distributions on the order of 10−5 and 10−6 mm decrease the fracture probability of the sample, whereas uniform particle size distributions on the order of 10−1 and 10−2 mm do not change the distribution probability. The paper shows that uneven distribution of Al2 O3 fillers in composite samples made using FDM printing technology leads to brittle fracture of the samples. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
20. Microstructure and Mechanical Properties of Core-Shell B 4 C-Reinforced Ti Matrix Composites.
- Author
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Xiu, Ziyang, Ju, Boyu, Zhan, Junhai, Zhang, Ningbo, Wang, Pengjun, Zhao, Keguang, Liu, Mingda, Yin, Aiping, Chen, Weidi, Jiao, Yang, Wang, Hao, Li, Shuyang, Zhu, Xiaolin, Wu, Ping, and Yang, Wenshu
- Subjects
TITANIUM composites ,MICROSTRUCTURE ,BORON carbides ,THERMAL conductivity ,COMPOSITE materials ,TITANIUM carbide - Abstract
Composite material uses ceramic reinforcement to add to the metal matrix to obtain higher material properties. Structural design is an important direction of composite research. The reinforcement distribution of the core-shell structure has the unique advantages of strong continuity and uniform stress distribution. In this paper, a method of preparing boron carbide (B
4 C)-coated titanium (Ti) powder particles by ball milling and preparing core-shell B4 C-reinforced Ti matrix composites by Spark Plasma Sintering was proposed. It can be seen that B4 C coated on the surface of the spherical Ti powder to form a shell structure, and B4 C had a certain continuity. Through X-ray diffraction characterization, it was found that B4 C reacted with Ti to form layered phases of titanium boride (TiB) and titanium carbide (TiC). The compressive strength of the composite reached 1529.1 MPa, while maintaining a compressive strain rate of 5%. At the same time, conductivity and thermal conductivity were also characterized. The preparation process of the core-shell structure composites proposed in this paper has high feasibility and universality, and it is expected to be applied to other ceramic reinforcements. This result provides a reference for the design, preparation and performance research of core-shell composite materials. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
21. MECHANICAL PROPERTIES OF POLYMER-MATRIX CELLULOSE-BASED COMPOSITE MATERIALS.
- Author
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Duşunceli, Necmi and Surme, Seckin
- Subjects
MECHANICAL properties of polymers ,COMPOSITE materials ,POLYETHYLENE ,TENSILE tests ,WASTE treatment - Abstract
Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
22. Mechanical Performance and Strengthening Mechanism of Polymer Concretes Reinforced with Carbon Nanofiber and Epoxy Resin.
- Author
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Li, Zhenfang, Liu, Aizhu, Gao, Dong, Wu, Chuanji, Liu, Xin, and Zhai, Haoran
- Subjects
POLYMER-impregnated concrete ,REINFORCED concrete ,EPOXY resins ,CARBON fibers ,CONCRETE durability ,COMPOSITE materials - Abstract
To address the issues of the brittleness, low tensile strength, insufficient bond strength, and reduced service life associated with ordinary cement concrete being used as a repair material, a water-based epoxy (WBE) and carbon-nanofiber-reinforced concrete composite repair material was designed, and the mechanical properties, bonding performance, and durability of the concrete modified using WBE and carbon fiber under various WBE contents were investigated and evaluated. In this paper, a self-emulsifying water-based epoxy curing agent with reactive, rigid, flexible, and water-soluble chains was obtained via chemical grafting, involving the incorporation of polyethylene glycol chain segments into epoxy resin molecules. The results demonstrated that a WBE has a contributing effect on improving the weak interfacial bond between the carbon fiber and concrete; moreover, the composite admixture of carbon fiber and WBE improves the mechanical properties and durability of concrete, in which the composite admixture of 1% carbon fiber and 10% WBE has the best performance. The flexural strength and chlorine ion permeability resistance of concrete were slightly reduced after more than 10% admixture, but bond strength, tensile strength, compressive strength, dry shrinkage resistance, and frost resistance were promoted. The addition of WBE significantly retards the cement hydration process while greatly improving the compactness and impermeability of the concrete. Furthermore, the combined effects of WBE and carbon fiber effectively prevented the generation and expansion of cracks. The interaction mechanism and microstructure evolution between the WBE, carbon fiber, and cement hydration were described by clarifying the mineral composition, organic–inorganic interactions, the evolution of the hydration products, and composite morphology at different scales. Carbon fiber and WBE exhibited synergistic effects on the tensile strength, ductility, and crack resistance of concrete. In the formed three-dimensional network structural system of concrete, the WBE formed an organic coating layer on the fiber surface and provided fiber protection as well as interfacial bonding reinforcement for the embedded cement particles. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
23. Mechanical, Thermal, and Acoustic Properties of Hemp and Biocomposite Materials: A Review.
- Author
-
Dahal, Raj Kumar, Acharya, Bishnu, and Dutta, Animesh
- Subjects
HEMP ,CLIMATE change ,ABSORPTION of sound ,THERMAL conductivity ,NATURAL fibers ,THERMAL properties ,COMPOSITE materials - Abstract
Bio-based products are paving a promising path towards a greener future and helping win the fight against climate change and global warming mainly caused by fossil fuel consumption. This paper aims at highlighting the acoustic, thermal, and mechanical properties of hemp-based biocomposite materials. Change in sound absorption as a result of hemp fibers and hemp particle reinforcement are discussed in this paper. The thermal properties characterized by the thermal conductivity of the composites are also presented, followed by the mechanical properties and the current issues in biocomposite materials mainly containing hemp as a constituent element. Lastly, the effects of biofillers and biofibers on the various properties of the hemp-composite materials are discussed. This paper highlights the development of and issues in the field of hemp-based composite materials. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
24. Developments and Industrial Applications of Basalt Fibre Reinforced Composite Materials.
- Author
-
Chowdhury, Indraneel R., Pemberton, Richard, and Summerscales, John
- Subjects
FIBROUS composites ,BASALT ,BOROSILICATES ,COMPOSITE materials ,INDUSTRIALIZATION ,PRODUCT life cycle assessment - Abstract
Basalt mineral fibre, made directly from basalt rock, has good mechanical behavior, superior thermal stability, better chemical durability, good moisture resistance and can easily be recycled when compared to E-glass fibres (borosilicate glass is called 'E-glass' or 'electric al-grade glass' because of its high electrical resistance) which are traditionally used in structural composites for industrial applications. Industrial adoption of basalt fibre reinforced composites (FRC) is still very low mainly due to inadequate data and lower production volumes leading to higher cost. These reasons constrain the composites industry from seriously considering basalt as a potential alternative to conventional (e.g., E-glass) fibre reinforced composites for different applications. This paper provides a critical review of the state-of-the-art concerning basalt FRC highlighting the increasing trend in research and publications related to basalt composites. The paper also provides information regarding physico-chemical, and mechanical properties of basalt fibres, some initial Life cycle assessment inventory data is also included, and reviews common industrial applications of basalt fibre composites. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
25. Recent Progress on Natural Fibers Mixed with CFRP and GFRP: Properties, Characteristics, and Failure Behaviour.
- Author
-
Nugraha, Ariyana Dwiputra, Nuryanta, Muhammad Irfan, Sean, Leonard, Budiman, Kresna, Kusni, Muhammad, and Muflikhun, Muhammad Akhsin
- Subjects
NATURAL fibers ,HYBRID materials ,SYNTHETIC fibers ,COMPOSITE materials ,LAMINATED materials ,GLASS fibers - Abstract
Research on natural-fiber-reinforced polymer composite is continuously developing. Natural fibers from flora have received considerable attention from researchers because their use in biobased composites is safe and sustainable for the environment. Natural fibers that mixed with Carbon Fiber and or Glass Fiber are low-cost, lightweight, and biodegradable and have lower environmental influences than metal-based materials. This study highlights and comprehensively reviews the natural fibers utilized as reinforcements in polyester composites, including jute, bamboo, sisal, kenaf, flax, and banana. The properties of composite materials consisting of natural and synthetic fibers, such as tensile strength, flexural strength, fatigue, and hardness, are investigated in this study. This paper aims to summarize, classify, and collect studies related to the latest composite hybrid science consisting of natural and synthetic fibers and their applications. Furthermore, this paper includes but is not limited to preparation, mechanism, characterization, and evaluation of hybrid composite laminates in different methods and modes. In general, natural fiber composites produce a larger volume of composite, but their strength is weaker than GFRP/CFRP even with the same number of layers. The use of synthetic fibers combined with natural fibers can provide better strength of hybrid composite. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
26. Research Progress of Low Density and High Stiffness of Be-Al Alloy Fabricated by Investment Casting.
- Author
-
Li, Junyi, Xie, Yao, Yang, Yiqun, Liu, Zhaogang, Wang, Dongxin, and Yin, Yajun
- Subjects
INVESTMENT casting ,ELECTRON beam welding ,METALLIC composites ,COMPOSITE materials ,ALLOYS ,HEAT treatment ,LIGHTWEIGHT materials - Abstract
Be-Al alloy is a type of in situ metal matrix composite composed of a primary Be phase for strength and stiffness and a continuous Al matrix for ductility and toughness. Be-Al alloy (AlBe-Cast
® 910) has the characteristics of low density (2.17 g/cm3 ), high elastic modulus (193 GPa) and specific stiffness (88.94 GPa/(g/cm3 )) as a preferred material for lightweight aerospace products. Investment casting technology can be employed to prepare the components with thin-walled complex structures for aerospace; however, the wide solidification range for Be-Al leads to difficulty in feeding a casting and results in extensive shrinkage and porosity in cast parts. In this paper, the characteristics of Be-Al alloy are introduced first. Secondly, the mechanisms of influence of adding elements on the casting process, mechanical properties (strength increases more than 20% by adding elements) and microstructure evolution are explained in detail. In addition, the heat treatment technology (strength increases at least 10% after heat treatment) and the repair of defects by electron beam welding are discussed. Finally, Be-Al alloy is a new type of composite material, and China is a major research and application country; this paper introduces its research status and analyzes existing problems and shortcomings and points out the direction of Be-Al alloy development in China in the next few years. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
27. Artificial Intelligence in Predicting Mechanical Properties of Composite Materials.
- Author
-
Kibrete, Fasikaw, Trzepieciński, Tomasz, Gebremedhen, Hailu Shimels, and Woldemichael, Dereje Engida
- Subjects
DEEP learning ,MECHANICAL behavior of materials ,ARTIFICIAL intelligence ,MECHANICAL ability ,MACHINE learning ,COMPOSITE materials - Abstract
The determination of mechanical properties plays a crucial role in utilizing composite materials across multiple engineering disciplines. Recently, there has been substantial interest in employing artificial intelligence, particularly machine learning and deep learning, to accurately predict the mechanical properties of composite materials. This comprehensive review paper examines the applications of artificial intelligence in forecasting the mechanical properties of different types of composites. The review begins with an overview of artificial intelligence and then outlines the process of predicting material properties. The primary focus of this review lies in exploring various machine learning and deep learning techniques employed in predicting the mechanical properties of composites. Furthermore, the review highlights the theoretical foundations, strengths, and weaknesses of each method used for predicting different mechanical properties of composites. Finally, based on the findings, the review discusses key challenges and suggests future research directions in the field of material properties prediction, offering valuable insights for further exploration. This review is intended to serve as a significant reference for researchers engaging in future studies within this domain. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Fabrication of High-Performance Natural Rubber Composites with Enhanced Filler–Rubber Interactions by Stearic Acid-Modified Diatomaceous Earth and Carbon Nanotubes for Mechanical and Energy Harvesting Applications.
- Author
-
Alam, Md Najib, Kumar, Vineet, Jung, Han-Saem, and Park, Sang-Shin
- Subjects
DIATOMACEOUS earth ,MECHANICAL energy ,ENERGY harvesting ,RUBBER ,CARBON nanotubes ,MECHANICAL loads ,COMPOSITE materials - Abstract
Mechanical robustness and high energy efficiency of composite materials are immensely important in modern stretchable, self-powered electronic devices. However, the availability of these materials and their toxicities are challenging factors. This paper presents the mechanical and energy-harvesting performances of low-cost natural rubber composites made of stearic acid-modified diatomaceous earth (mDE) and carbon nanotubes (CNTs). The obtained mechanical properties were significantly better than those of unfilled rubber. Compared to pristine diatomaceous earth, mDE has higher reinforcing efficiencies in terms of mechanical properties because of the effective chemical surface modification by stearic acid and enhanced filler–rubber interactions. The addition of a small amount of CNT as a component in the hybrid filler systems not only improves the mechanical properties but also improves the electrical properties of the rubber composites and has electromechanical sensitivity. For example, the fracture toughness of unfilled rubber (9.74 MJ/m
3 ) can be enhanced by approximately 484% in a composite (56.86 MJ/m3 ) with 40 phr (per hundred grams of rubber) hybrid filler, whereas the composite showed electrical conductivity. At a similar mechanical load, the energy-harvesting efficiency of the composite containing 57 phr mDE and 3 phr CNT hybrid filler was nearly double that of the only 3 phr CNT-containing composite. The higher energy-harvesting efficiency of the mDE-filled conductive composites may be due to their increased dielectric behaviour. Because of their bio-based materials, rubber composites made by mDE can be considered eco-friendly composites for mechanical and energy harvesting applications and suitable electronic health monitoring devices. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
29. Research and Development of Self-Waterproofing Concrete for Tunnel Lining Structure and Its Impermeability and Crack Resistance Characteristics.
- Author
-
Li, Huayun, Zhou, Anxiang, Wu, Yangfan, Deng, Lai, Zhu, Kaicheng, and Lu, Feng
- Subjects
POLYPROPYLENE fibers ,TUNNEL lining ,CONCRETE durability ,CONCRETE ,FLY ash ,COMPOSITE materials - Abstract
This research paper systematically investigates the combined influence of fly ash, cementitious capillary crystalline waterproofing (CCCW) materials, and polypropylene fibers on the mechanical properties and impermeability of concrete through comprehensive orthogonal tests. Microscopic morphological changes in the concrete induced by different composite materials are examined via scanning electron microscopy (SEM) and X-ray diffraction (XRD) testing. The objective is to facilitate a beneficial synergetic interaction among these materials to develop highly permeable, crack-resistant concrete. Key findings of this study are: (1) The study unveils the impact of the concentration of three additive materials on the concrete's compressive strength, tensile strength, and penetration height, thereby outlining their significant influence on the mechanical properties and impermeability of the concrete; (2) An integrated scoring method determined the optimal composite dosage of three materials: 15% fly ash, 2% CCCW, and polypropylene fibers at 1.5 kg/m
3 . This combination increased the concrete's compressive strength by 12.5%, tensile strength by 48.4%, and decreased the average permeability height by 63.6%; (3) The collective introduction of these three materials notably augments the hydration reaction of the cement, resulting in denser concrete microstructure, enhanced bonding between fibers and matrix, and improved concrete strength and durability. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
30. Novel Sustainable Composites Incorporating a Biobased Thermoplastic Matrix and Recycled Aerospace Prepreg Waste: Development and Characterization.
- Author
-
Butenegro, José Antonio, Bahrami, Mohsen, Swolfs, Yentl, Ivens, Jan, Martínez, Miguel Ángel, and Abenojar, Juana
- Subjects
THERMOPLASTIC composites ,CARBON fiber-reinforced plastics ,INCORPORATION ,POLYAMIDES ,DYNAMIC mechanical analysis ,COMPOSITE materials ,IMPACT testing - Abstract
Carbon fiber-reinforced polymer (CFRP) composite materials are widely used in engineering applications, but their production generates a significant amount of waste. This paper aims to explore the potential of incorporating mechanically recycled aerospace prepreg waste in thermoplastic composite materials to reduce the environmental impact of composite material production and promote the use of recycled materials. The composite material developed in this study incorporates a bio−based thermoplastic polymer, polyamide 11 (PA11), as the matrix material and recycled aerospace prepreg waste quasi-one-dimensionally arranged as reinforcement. Mechanical, thermal, and thermomechanical characterizations were performed through tensile, flexural, and impact tests, as well as differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Compared to previous studies that used a different recycled CFRP in the shape of rods, the results show that the recycled prepregs are a suitable reinforcement, enhancing the reinforcement-matrix adhesion and leading to higher mechanical properties. The tensile results were evaluated by SEM, and the impact tests were evaluated by CT scans. The results demonstrate the potential of incorporating recycled aerospace prepreg waste in thermoplastic composite materials to produce high-performance and sustainable components in the aerospace and automotive industries. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
31. Effect of the Reinforcing Particle Introduction Method on the Tribomechanical Properties of Sintered Al-Sn-Fe Alloys.
- Author
-
Rusin, Nikolay M., Skorentsev, Alexander L., and Dmitriev, Andrey I.
- Subjects
IRON powder ,COMPOSITE structures ,ALUMINUM powder ,ALLOYS ,COMPOSITE materials ,ULTIMATE strength - Abstract
The present paper reports the results of the comparative study of mechanical properties of sintered disperse-strengthened Al–40Sn alloy depending on the method of reinforcing particle introduction. The study is performed on two mixtures of aluminum and tin powders: one is admixed with 5.5–14.6 wt% of pure iron powder and the other contains the same amount of iron, but as a component of aluminide Al
3 Fe powders. The volume fraction of tin remains unchanged in all mixtures, being equal to 20%, and the concentration of hard particles increases due to a decrease in the volume fraction of the aluminum phase. Green compacts are sintered in the vacuum furnace at a temperature above the melting point of aluminum. The sintered material is a composite containing three phases: α-Al, β-Sn, and Al3 Fe, in which the tin volume fraction is constant. Testing of the sintered composites for compression shows that the addition of finished Al3 Fe particles has a more beneficial effect on their mechanical properties as compared to the addition of pure iron powders. In the latter case, aluminides are formed during sintering. The ultimate strength of composites reaches 180 MPa. Mechanisms of sintering of composites and the related structure and mechanical properties are discussed. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
32. Effect of TiC Particle Size on Processing, Microstructure and Mechanical Properties of an Inconel 718/TiC Composite Material Made by Binder Jetting Additive Manufacturing.
- Author
-
Sufiiarov, Vadim, Borisov, Artem, Popovich, Anatoly, and Erutin, Danil
- Subjects
BINDING agents ,INCONEL ,ISOSTATIC pressing ,TITANIUM carbide ,HEAT treatment ,POWDERS ,COMPOSITE materials - Abstract
In this paper, the effect of TiC particle size on the microstructure and mechanical properties of an Inconel 718/TiC composite material fabricated using binder jetting additive manufacturing was investigated. Vacuum sintering, hot isostatic pressing and heat treatment as post-processing were applied to the samples. The addition of 1 wt% micron-sized TiC to the Inconel 718 matrix resulted in a significant increase in strength and relative elongation during tensile tests at both room temperature and 700 °C. The distribution of micron-sized TiC particles in the matrix was uniform, and the MC phase precipitated after HT was located along the grain boundaries and near the micron-sized TiC particles, which contributed to the strengthening. The hardness increased insignificantly with the addition of micron-sized TiC. The nano-sized TiC particles added to the matrix were located on the surfaces of the Inconel 718 particles of the initial powders, which obstructed sintering and resulted in a porous structure and, consequently, low mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Effect of CaF 2 @SiO 2 on Si 3 N 4 /TiC Composite Ceramic Materials: Molecular Dynamics Analysis and Material Preparation.
- Author
-
Li, Xuequan, Chen, Zhaoqiang, Li, Qi, Chen, Hui, Xiao, Guangchun, Yi, Mingdong, Zhang, Jingjie, Zhou, Tingting, and Xu, Chonghai
- Subjects
MATERIALS analysis ,CERAMIC materials ,MOLECULAR dynamics ,COMPOSITE materials ,MODULUS of elasticity - Abstract
Molecular dynamics simulations allow to investigate the microscopic evolution of a structure, and can also point the way to tool material design. In this paper, the effect of adding CaF
2 and CaF2 @SiO2 on the Si3 N4 /TiC system is studied using molecular dynamics simulations. The results show that the system with the addition of CaF2 @SiO2 to the model has a higher hardness than the system with the addition of CaF2 . In order to obtain the optimum parameters for self-lubricating ceramic tools, the effect of adding different amounts of CaF2 @SiO2 on the Si3 N4 /TiC system was investigated. The Si3 N4 /TiC/CaF2 @SiO2 system achieved optimum mechanical properties when four CaF2 @SiO2 were included in the model. By analyzing the effect of the sintering temperature on the system, it was deduced that the hardness achieved a maximum value of 15.89 GPa and the modulus of elasticity reached 132.53 GPa when the sintering temperature was at 2073 K. Based on this sintering parameter, the Si3 N4 /TiC/CaF2 @SiO2 composite ceramic tool material was experimentally prepared with the mechanical properties of 15.66 GPa hardness and 128.08 GPa modulus of elasticity. The experimental results were consistent with the simulation results. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
34. Study on Thermal Conductivity and Mechanical Properties of Cyclotriphosphazene Resin-Forced Epoxy Resin Composites.
- Author
-
Dagdag, Omar, El Gana, Lahoucine, Haldhar, Rajesh, Berisha, Avni, Kim, Seong-Cheol, Berdimurodov, Elyor, Hamed, Othman, Jodeh, Shehdeh, Akpan, Ekemini Daniel, and Ebenso, Eno Effiong
- Subjects
EPOXY resins ,THERMAL conductivity ,GLASS transition temperature ,YOUNG'S modulus ,MOLECULAR dynamics ,COMPOSITE materials - Abstract
Cyclotriphosphazenes, a variety of inorganic rings together with a curing ingredient, 4,4′-methylene dianiline (MDA), are mainly used to enhance the thermal conductivity and mechanical characteristics of epoxy resin (DGEBA). Three DGEBA@MDA, HGCP@MDA, and thermosets were produced, and their curing behaviors were investigated. Using a molecular dynamics (MD) approach, the impact of cyclotriphosphazene on the characteristics of DGEBA composites is thoroughly explored in this paper. Results indicated that the glass transition temperatures (T
g ) of DGEBA containing HGCP had slightly decreased compared to DGEBA. With the addition of HGCP to DGEBA, epoxy resin (DGEBA@HGCP@MDA) has a high thermal conductivity of 0.215284 W/m·K, with an increase of 116.04% more than pure DGEBA (0.185524 W/m·K). Moreover, the DGEBA@HGCP@MDA composite has high mechanical strength with a specific Young's modulus of 5.4902 GPa. In order to forecast and analyze certain performances directly associated with the microstructure characteristics of the various cross-linked resin systems and their composite materials, an MD simulation approach will be quite valuable. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
35. Advanced Configuration Parameters of Post Processor Influencing Tensile Testing PLA and Add-Mixtures in Polymer Matrix in the Process of FDM Technology.
- Author
-
Török, Jozef, Törökova, Monika, Duplakova, Darina, Murcinkova, Zuzana, Duplak, Jan, Kascak, Jakub, and Karkova, Monika
- Subjects
POLYLACTIC acid ,TENSILE tests ,POLYMERS ,COMPOSITE materials ,TENSILE strength ,SURFACE structure ,IRON composites - Abstract
The present paper focuses on the configuration possibilities of post -processor influencing mechanical properties of a given test sample produced by the FDM printer from different materials. The research consists of assessing the composite material configurations through a static tensile test conducted on 80 samples produced. The samples were produced based on ISO 527-2 standard, type 1A, with a horizontal position and a layer height of 0.2 mm. The individual samples consisted of four basic groups of materials—the pure Polylactic acid (PLA) plastic (reference sample), and three composite samples with admixtures—PLA matrix with a copper admixture, PLA matrix with an iron admixture, and PLA matrix with a steel admixture. The static tensile test was conducted at a test speed of 5 mm/min. During the research, reference samples (pure PLA) were assessed in five orientations. Samples made of the PLA composite materials with admixtures were manufactured, tested, and evaluated only in the 0° orientation. The paper concludes by comparing the results of measurement with the original material, free from additives, and with the researched influence of the orientation of the prints on the resulting mechanical properties of shear samples and their surface structure. In the conducted experiments, the lowest tensile strength has been demonstrated in test samples the orbital transitions and the upper surface layers of which were parallel to the infill. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
36. Molecular dynamics study of the mechanical properties of hydrated calcium silicate enhanced by functionalized carbon nanotubes.
- Author
-
Wei, Lin, Liu, GuiLi, Qian, ShaoRan, Zhao, JingWei, Jiao, Gan, and Zhang, GuoYing
- Subjects
- *
CALCIUM silicates , *MOLECULAR dynamics , *CARBON nanotubes , *CALCIUM silicate hydrate , *MECHANICAL behavior of materials , *COMPOSITE materials - Abstract
Context: The incorporation of functionalized carbon nanotubes can enhance the mechanical properties of cement-based materials. However, the types of functional groups and their roles in composite materials are not yet clear. In this study, molecular dynamics (MD) simulation methods were employed to investigate the mechanical performance of hybridized calcium silicate hydrate gel reinforced with pure carbon nanotubes, epoxy-coated carbon nanotubes, carboxylated carbon nanotubes, and hydroxylated carbon nanotubes. The results indicate that the addition of all four types of nanotubes can enhance the mechanical properties of hydrated calcium silicate gel compared to pure C–S–H. Tensile loading results show that carbon nanotubes can act as bridges for microcracks in the composite material, and functionalized nanotubes exhibit a better reinforcing effect than pure carbon nanotubes. Under tensile stress, hydroxylated nanotubes are more effective in increasing the toughness of the composite material, while carboxylated nanotubes tend to enhance the strength of the composite material. The compressive loading results indicate that the compressive strength of cement-based materials is higher than their tensile strength. Overall, carboxylated nanotubes show particularly remarkable performance in enhancing the mechanical properties of cement-based materials. Compared to pure C–S–H gel, the tensile and compressive elastic moduli of carboxylated nanotube/C–S–H composite material increased by 18.13% and 34.78%, respectively. Its tensile and compressive strengths also increased by 30.40% and 40.23%, respectively. Method: All molecular dynamics simulations were performed on the classical computational simulation platform LAMMPS. In this paper, the parameters in the ClayFF force field are chosen to simulate calcium hydrated silicate (/C–S–H), and the ClayFF-CVFF combined force field is used to simulate the mechanical properties of the CNT/C–S–H molecular model structure. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
37. Recent Development in the Processing, Properties, and Applications of Epoxy-Based Natural Fiber Polymer Biocomposites.
- Author
-
Alsuwait, Raed B., Souiyah, Miloud, Momohjimoh, Ibrahim, Ganiyu, Saheed Adewale, and Bakare, Azeez Oladipupo
- Subjects
NATURAL fibers ,SYNTHETIC fibers ,BIOPOLYMERS ,FIBROUS composites ,INTERFACIAL bonding ,COMPOSITE materials ,EPOXY resins - Abstract
Growing environmental concerns have increased the scientific interest in the utilization of natural fibers for the development of epoxy biocomposite materials. The incorporation of one or more fibers in the production of hybrid epoxy polymer composites has been a subject of discussion. It is interesting to acknowledge that natural/synthetic fiber hybridized epoxy composites have superior properties over natural/natural fiber hybridized epoxy composites. Significant efforts have been devoted to the improvement of natural fiber surface modifications to promote bonding with the epoxy matrix. However, to achieve sufficient surface modification without destroying the natural fibers, optimization of treatment parameters such as the concentration of the treatment solution and treatment time is highly necessary. Synthetic and treated natural fiber hybridization in an epoxy matrix is expected to produce biocomposites with appreciable biodegradability and superior mechanical properties by manipulating the fiber/matrix interfacial bonding. This paper presents a review of studies on the processing of epoxy natural fiber composites, mechanical properties, physical properties such as density and water absorption, thermal properties, biodegradability study, nondestructive examination, morphological characterizations, and applications of epoxy-based natural fiber biocomposites. Other aspects, including a review of variables that enhance the mechanical and functional performance of epoxy/natural fibers composites while also increasing the biodegradability of the composite material for environmental sustainability, were presented. The future research focus was elucidated. It is hoped that this review will stimulate and refocus research efforts toward advancing the manufacture of epoxy/natural fiber composites to meet the growing demand for biocomposite materials in the global world. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Evaluation of the Tensile Characteristics and Bond Behaviour of Steel Fibre-Reinforced Concrete: An Overview.
- Author
-
Mujalli, Mohammed A., Dirar, Samir, Mushtaha, Emad, Hussien, Aseel, and Maksoud, Aref
- Subjects
STEEL ,CONCRETE ,SHEAR strength ,FLEXURAL strength ,CONSTRUCTION materials ,COMPOSITE materials - Abstract
Conventional concrete is a common building material that is often ridden with cracks due to its low tensile strength. Moreover, it has relatively low shear strength and, unless reinforced, undergoes brittle failure under tension and shear. Thus, concrete must be adequately reinforced to prevent brittle tensile and shear failures. Steel fibres are commonly used for this purpose, which can partially or fully replace traditional steel reinforcement. The strength properties and bond characteristics between reinforcing steel fibres and the concrete matrix are crucial in ensuring the effective performance of the composite material. In particular, the quality of the bond has a significant impact on crack development, crack spacing, and crack width, among other parameters. Hence, the proper application of steel fibre-reinforced concrete (SFRC) requires a thorough understanding of the factors influencing its bond behaviour and strength properties. This paper offers a comprehensive review of the main factors controlling the bond behaviour between concrete and steel fibres in SFRC. In particular, we focus on the effects of the physical and mechanical properties of steel fibres (e.g., geometry, inclination angle, embedded length, diameter, and tensile strength) on the bond behaviour. We find that the addition of up to 2% of steel fibres into concrete mixtures can significantly enhance the compressive strength, tensile strength, and flexural strength of concrete components (by about 20%, 143%, and 167%, respectively). Furthermore, a significant enhancement in the pull-out performance of the concrete is observed with the addition of steel fibres at various dosages and geometries. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
39. Determination of the Mechanical Characteristics of the Ideal Ceramic (Diamond–Silicon Carbide Composite).
- Author
-
Shevchenko, V. Ya., Oryshchenko, A. S., Belyakov, A. N., and Perevislov, S. N.
- Subjects
- *
POISSON'S ratio , *SILICON carbide , *BULK modulus , *MODULUS of rigidity , *SPEED of sound , *CERAMIC materials , *COMPOSITE materials - Abstract
In this paper, a new diamond–silicon carbide ceramic composite material—Ideal—is studied and its mechanical characteristics are determined. For the first time, a comprehensive determination of Poisson's ratio, shear modulus, bulk modulus, and transverse sound velocity is carried out. Poisson's ratio is in the region of 0.008 to 0.01, which, in turn, indicates the absolutely brittle nature of the failure of the Ideal ceramic under loading. The criteria that allow evaluating different materials used for body armor are calculated. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. Foamed concrete composites: Mn–Zn ferrite/carbon fiber synergy enhances electromagnetic wave absorption performance.
- Author
-
Bai, Ying-hua, Zhang, De-yue, and Lu, Yao
- Subjects
- *
ELECTROMAGNETIC wave absorption , *CARBON fibers , *CARBON-based materials , *EDDY current losses , *FOAM , *FERRITES , *MAGNETIC flux leakage , *COMPOSITE materials - Abstract
In order to achieve multi-functional integration of materials and reduce electromagnetic pollution in the building environment, this paper uses foam concrete as a base, combined with magnetic loss absorbing material Mn–Zn ferrite (MZF) and resistance absorbing material carbon fiber to prepare a composite material with outstanding electromagnetic wave (EMW) absorption performance. The EMW absorption performance and mechanisms of the composites in the 0.2–5 GHz frequency range were studied, and the mechanical properties, hydration products, aperture parameters, and conductivity of the composites were analyzed. The results demonstrate that the magnetic loss of MZF in composites primarily comes from eddy current loss, domain wall resonance loss, and natural resonance loss. The combination of MZF and carbon fiber not only synergizes the electromagnetic loss capability, but also improves the impedance matching of the composite material, significantly enhancing the EMW absorption effect. The minimum reflection loss of the composite material in the tested frequency band is −28.75 dB (2.10 GHz, thickness 10 mm) and the effective absorption bandwidth is 1.46 GHz (2.29–3.75 GHz) at a thickness of 5.8 mm. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Mechanical and Tribological Behavior of Functionally Graded Unidirectional Glass Fiber-Reinforced Epoxy Composites.
- Author
-
Alhazmi, Waleed, Jazaa, Yosef, Althahban, Sultan, Mousa, Saeed, Abu-Sinna, Ahmed, Abd-Elhady, Amr, Sallam, Hossam El-Din, and Atta, Mahmoud
- Subjects
GLASS-reinforced plastics ,COHESIVE strength (Mechanics) ,POLYMERIC composites ,GLASS fibers ,COMPOSITE numbers ,COMPOSITE materials ,FRACTURE mechanics - Abstract
This paper aims to assess experimentally the mechanical and tribological behavior of conventional and functionally graded (FG) polymeric matrix composites reinforced with continuous glass fibers. The small punch test (SPT) and a pin-on-disc device were used in the present work to examine the mechanical and wear behavior, respectively. The hand lay-up technique was used in the present investigation to manufacture the conventional and FG composites. Various wooden looms with different nailed spacing were employed to manufacture the FG composites. According to test type, the FG composite is composed of four and ten layers, with a different glass fiber volume of fraction (V
f %) for each layer. In addition, the finite element simulation based on Hashin's failure criterion and cohesive zone modeling was used to show the progressive failure and give more explanation regarding the flexural behavior of such composites. The present results indicate that the wear rate of an FG composite could be affected by many factors, including the disk speed, applied load, the composite layers number, and average glass fiber volume fraction. On the other hand, the arrangement of layers in the composite materials by variation of Vf % for each layer can improve the wear rate and value of the ultimate load before the fracture of the composite material when subjected to SPT. The experimental and numerical results for all SPT specimens showed that the fracture of the SPT specimens began beneath the punch tip and grew along the fiber direction. The ultimate flexural capacity of FG composites increased by 30% compared with the conventional composites. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
42. Microstructure and Mechanical Properties of TiAl Matrix Composites Reinforced by Carbides.
- Author
-
Yang, Ying, Liang, Yongfeng, Li, Chan, and Lin, Junpin
- Subjects
MICROSTRUCTURE ,SOLUTION strengthening ,CARBIDES ,FLEXURAL strength ,LIGHTWEIGHT materials ,BRITTLENESS ,COMPOSITE materials - Abstract
TiAl alloys have the potential to become a new generation of high-temperature materials due to their lightweight and high-strength properties, while the brittleness at room temperature and microstructure stability at elevated temperature are the key problems. The preparation of composite materials is an effective way to solve these problems, because the mechanical properties of TiAl matrix composites can be improved by the close combination of the reinforced phase and matrix. The preparation methods, microstructure, and mechanical properties of TiAl matrix composites reinforced by carbides are reviewed from the literature in this paper. A comprehensive summary of the effect of C on TiAl alloys can reveal the relationship between the microstructure and mechanical properties and provide guidance for subsequent experimental works. Two forms of C in TiAl matrix composites are reviewed: solid solutions in matrix and carbide precipitations. For TiAl alloys, the minimum carbon content for the carbide precipitation is about 0.5 at.% for low-Nb-containing TiAl alloys and about 0.8 at.% for high-Nb-TiAl alloys. An appropriate amount of C can improve the tensile properties and flexural strength of TiAl alloys. The hardness of the composites is higher than that of pure TiAl due to solution strengthening when the carbon content is low. The minimum creep rate of TiAl alloys can be reduced by one order of magnitude by adding C at the amount near the solubility limit. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
43. Evaluation of the Optimal Uses of Five Genotypes of Musa textilis Fiber Grown in the Tropical Region.
- Author
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Valverde, Juan Carlos, Araya, Mónica, Arias-Aguilar, Dagoberto, Masís, Charlyn, and Muñoz, Freddy
- Subjects
GENOTYPES ,BANANAS ,CHEMICAL properties ,COMPOSITE materials ,FIBERS ,BIODEGRADABLE plastics - Abstract
Knowing the genotypes of Musa textilis and its fiber production properties is key for developing cultivars with homogeneous properties and focusing on specific products or market segments that generate added value to the fiber. For this reason, the objective was to determine the optimal use of five genotypes of M. textilis (MT01, MT03, MT07, MT11, and CF01) with high productivity grown in the tropical region of Costa Rica. Therefore, anatomical, physical-mechanical, chemical, and energetic analyses were carried out on these fibers to define whether any genotype has the ideal conditions for a specific use. The results showed differences between the genotypes, obtaining significant differences in physical-mechanical properties (tension, water retention, and color), chemical properties (holocellulose, lignin, extractives, and elemental values of nitrogen, carbon, and sulfur), and energetic properties (volatiles, ash, and caloric value thermogravimetric analyses), which resulted in the establishment of two groups of genotypes with a dissimilarity degree of 35%. The first group, composed of MT03 and MT01, presented characteristics suitable for paper production, biodegradable materials, and composite materials. On the other hand, the second group, made up of MT07, MT11, and CF01, showed properties suitable for textiles, heavy-duty fibers, and bioenergy. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
44. Fresh and Hardened Properties of Self-Compacting Concrete Reinforced with Hybrid Recycled Steel–Polypropylene Fiber.
- Author
-
Mastali, M. and Dalvand, A.
- Subjects
CEMENT ,ASPHALT concrete ,AMORPHOUS substances ,POLYPROPYLENE fibers ,COMPOSITE materials ,CIVIL engineering equipment ,ENGINEERING equipment ,STRUCTURAL analysis (Engineering) equipment - Abstract
This paper presents the results of extensive experimental tests on the fresh and hardened properties of self-compacting concrete reinforced with hybrid polypropylene (PP) fiber and recycled steel fiber (RSF) in different fiber volume fractions. In the present paper, RSFs were recovered from waste tires. The mix compositions were reinforced with different combinations of hybrid recycled-steel fiber (0.35, 0.7, and 1.05%) and PP fiber (0.35 and 0.7%). The fresh state of the mix compositions were assessed by using slump flow diameter, T500, and Tv. Moreover, the hardened properties of specimens were characterized by using compressive strength, flexural strength, and impact resistance. Regression analysis was executed on the relatively large amount of gathered experimental data to correlate properties of fresh and hardened states of self-compacting concrete reinforced with hybrid recycled steel–PP fibers. The results showed that adding hybrid recycled steel–PP fiber improves the impact resistance and mechanical properties. Adding recycled steel fiber led to higher improvement in the compressive strength compared to PP fiber. Moreover, increasing the content of PP fiber reduces the effect of recycled steel fiber in improvement of flexural strength. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
45. Multi-scale analyses on performance degradation of reinforced concrete structure due to damage evolution on bonding interface.
- Author
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Wang, Ying, Zheng, Yuqian, Wang, Xuan, and Li, Zhaoxia
- Subjects
REINFORCED concrete ,MULTISCALE modeling ,CRACKS in reinforced concrete ,FAILURE mode & effects analysis ,MATERIALS science ,PHYSICAL sciences - Abstract
Damage in the bonding interface is a major factor that leads to the degradation of macroscopic performance of reinforced concrete (RC) structure because the damage generally results in the debonding or slipping between reinforcement and concrete. Based on hierarchical mesh methodology, a multi-scale finite element (FE) model consisting of coarse aggregate, mortar and steel rebar was established to analyze the failure process of RC structure in this paper. In order to develop the mesoscopic FE model, Monte-Carlo method was used to randomly generate the size and position of coarse aggregates; a criterion of mesh reconstruction was proposed to separate the macroscopic mesh into the mesoscopic mesh and the mesh of transitional zone; the damage constitutive relation model for concrete presenting significant difference of its tensional and compressive properties was adopted to control the damage evolution in concrete when loading; the birth-death element method was used to adaptively reform the multi-scale FE model, and finally macroscopic performance degradation of RC structure was evaluated reasonably. A example of standard RC specimen under unaxial load was performed to verify both the accuracy and efficiency of the developed FE model in analyzing failure mode of RC specimen under unaxial tension and compression. By using the developed multiscale FE model, the destruction process of a four-point bending RC beam was analyzed. The simulation results coincide well with the test results from another literature. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
46. An experimental study on damaged cementitious mortars repaired by glass/epoxy composite materials
- Author
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Aribi Chouaib, Bouaissi Aissa, Safi Brahim, and Saidi Mohammed
- Subjects
cement mortar ,glass fiber ,damaged cementitious materials ,composite materials ,epoxy resin ,mechanical properties ,sem ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
This paper presents an experimental investigation on the post-repair flexural response of mortars with and without damage. In order to improve the mechanical properties of the damaged mortars, which were subjected to different loads ranging between 40 % and 90 %, the mortars specimens were reinforced and repaired using two different composite materials, the first with only epoxy resin, while the second consisted of a mixture of epoxy resin and glass fiber. The results show a significant improvement in the stiffness damaged. Therefore, the reinforced specimens by a layer of resin on the lower side surface increased the bending strength by 58 %, when compared to those control samples. The reinforcement using composite resin-fiber of glass exhibited considerable increases in the safety of constructions. The SEM images of damaged samples with and without repair, revealed the impact of reinforced glass fibers-mortar on the matrix-mortar by improving theirs mechanical performances.
- Published
- 2020
- Full Text
- View/download PDF
47. MACROSCOPIC MECHANICAL PROPERTIES AND MECHANISM OF SUPERFINE PORTLAND CEMENT-BASED COMPOSITE SEALING MATERIAL FOR GAS DRAINAGE.
- Author
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Sheng XUE, Xin GUO, Chunshan ZHENG, Yaobin LI, and Linfang Xie
- Subjects
PORTLAND cement ,COMPOSITE materials ,MICROCRACKS ,GROUTING ,MICROSTRUCTURE ,SEALING compounds - Abstract
Superfine Portland cement is a kind of inorganic grouting material widely used, which can be used to prepare cementitious material with short solidification time, high strength and good effect on micro-crack grouting, which is of great significance to the prevention and control of coal mine gas disaster. This paper combines macroscopic mechanical property test and microstructure observation to study the mechanical properties and mechanism, the hydration products, and microstructure of superfine cement-based composite sealing materials. The results show excessive additives will lead to defects and decrease the mechanical properties of the composite material. The results of SEM and XRD analysis show that the hydration of superfine cement-based sealing materials produces a large amount of Aft (Calcium aluminate hydrated from cement hydration products combined with sulfate ions can make cement structure more compact). The more sufficient the hydration, the more compact the overall microstructure and the higher the mechanical property. The study also shows that the composite material containing 8% expansion agent, 0.3% water reducer and 0.03% retarder has high mechanical properties and low cost. [ABSTRACT FROM AUTHOR]
- Published
- 2021
48. Effects of polymorphic form and particle size of SiO2 fillers on the properties of SiO2–PEEK composites.
- Author
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Xue, Peng Jie, Liu, Shi Lin, and Bian, Jian Jiang
- Subjects
POLYMORPHIC transformations ,COMPOSITE materials ,POLYETHER ether ketone ,POLYETHERS ,CONDUCTING polymers - Abstract
The effects of polymorphic form and particle size of SiO
2 fillers on the dielectric, mechanical and thermal properties of SiO2 –Polyetheretherketone (SiO2 –PEEK) composites were investigated in this paper. Strong low frequency (<10Hz) Debye-like dielectric dispersions could be observed for all samples. The dielectric permittivity at high frequencies of the composite exhibits little morphology or particle size-sensitive characteristics of the SiO2 fillers. All the composites obtained in this case demonstrate the dielectric permittivities of ∼ 3. 5 at high frequencies. The crystalline α -cristobalite filled composite exhibits lower dielectric loss and mechanical strength, but larger thermal expansion coefficient and thermal conductivity, compared with the similar particle sized amorphous SiO2 filled one. The crystalline α -quartz filled composite demonstrates the lowest mechanical strength and highest dielectric loss. An increase in particle size of the spherical fused silica fillers decreases the dielectric loss, while increases the thermal conductivity of the composite. The flexural strength of the composite reaches the maximum value of 113 MPa when the particle size of spherical SiO2 filler is ∼ 1 0 μ m. Particle packing by combining optimal amounts of differently sized spherical fused silica fillers leads to a substantial improvement of mechanical strength (153MPa) coupled with reasonable dielectric and thermal properties due to the synergic effect (dielectric permittivity ( r) = 3.35, dielectric loss (tan δ) = 1. 6 3 × 1 0 − 3 @10 GHz, thermal conductivity (λ) = 0.74 W/m*k (9 0 ∘ C), coefficient of thermal expansion (α) = 2 3. 6 ppm / ∘ C and relative density (ρ) = 99.72%). [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
49. Seismic collapse assessment of bridge piers constructed with steel fibers reinforced concrete.
- Author
-
Pang, Yutao and Li, Lingxu
- Subjects
BRIDGE failures ,SEISMIC response ,PIERS -- Design & construction ,FIBER-reinforced concrete ,METAL fibers - Abstract
Steel fiber is one of the most widely used reinforcements to improve the performance of concrete members. However, few studies have been proposed to study the seismic performance of bridge piers constructed with steel fiber reinforced concrete. This paper presents the collapse vulnerability assessment of typical single bridge piers constructed with steel fibers. Fiber element models of RC bridge piers with and without steel fibers are firstly built by selecting suitable cyclic constitutive laws of steel fiber reinforced concrete, and then calibrated using the experimental results. The seismic capacity and inelastic demand of RC piers with steel fibers are quantified using both nonlinear static pushover analyses and nonlinear incremental dynamic analyses (IDA). In order to conduct the IDA, a suite of 20 earthquake ground motions are selected and scaled to different levels of peak ground acceleration (PGA). Collapse fragility curves are then generated using the maximum drift ratio of piers as the engineering demand parameter (EDP). In order to investigate the impact of various parameters on the collapse fragility curves, six parameters are considered in the parametric study: peak compressive strength of concrete, yield strength of steel, longitudinal reinforcement ratio, axial load ratio, transverse hoops ratio and steel fiber content. It was observed that the concrete strength, longitudinal reinforcement ratio and steel fiber content could significantly affect the collapse fragility curve of the bridge piers with steel fibers. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
50. Development and Mechanical Characterisation of Al6061-Al2O3-Graphene Hybrid Metal Matrix Composites.
- Author
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Boppana, Satish Babu, Dayanand, Samuel, Murthy, Bharath Vedashantha, Nagaral, Madeva, Telagu, Aravinda, Kumar, Vijee, and Auradi, Virupaxi
- Subjects
GRAPHENE ,COMPOSITE materials ,ALUMINUM ,FLUID dynamics ,FRACTOGRAPHY - Abstract
MMC based on aluminium (Al) were produced for light-weight applications especially in aviation and automobile areas. Present paper deals with the fabrication and mechanical performance of AA6061 matrix composites fortified with Al
2 O3 (alumina) and graphene particulates. Fluid metallurgy method namely stir casting route was employed for fabricating the hybrid composites. Al2 O3 p and graphene powder are mixed in different weight fractions in which graphene (1 wt. %) particle reinforcement is held consistent and Al2 O3 reinforcement is differed freely with 5, 10 and 15 wt. %. Using optical analyser and SEM equipment, microstructural examination is carried out and the result reveals that the graphene and Al2 O3 particles prevalently are homogeneously appropriated on the grain limits of Al matrix and Al2 O3 particles are disseminated between graphene in the as-cast AA6061 MMC's. Detailed analysis on investigation of the microstructure and mechanical aspects of Al6061-graphene-Al2 O3 p composites is presented by following ASTM guidelines; results uncovered that with increment in reinforcement particles, there is an enhancement in the hardness, ultimate strength, yield strength and a decline in the elongation values was however noticed when contrasted with Al6061 alloy. Fractography investigation revealed dimples in unreinforced alloy and the composite. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
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