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1 – 10 of over 48000Jun Xiu Low, Poi Ngian Shek and Mahmood Md Tahir
Composite slabs are gaining wide acceptance in many countries as they lend themselves to faster, lighter and more economic in construction buildings. The strength of composite…
Abstract
Composite slabs are gaining wide acceptance in many countries as they lend themselves to faster, lighter and more economic in construction buildings. The strength of composite slabs system relies on the bonding action between the concrete and the steel deck, the shear connections and the cross-sectional resistance of steel beam. However, structural behaviour of composite slab is a complex phenomenon and therefore experimental study is often conducted to establish the actual strength of the structure under ultimate load capacity. The main objective of this study is to determine the structural behaviour of composite slab system until ultimate limit state. Total of two specimens are examined in order to obtain failure mechanism of the composite structure under full load capacity. A new design approach of composite slab for roofing system are proposed in this study to construct a composite slab system that can float in the water but not wash away by flood. The lightweight materials in this composite construction are cold-formed steel and foam concrete. The system focuses on the concept of Industrialised building system (IBS) to reduce the cost and construction time.
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Chaofan Jia, Shaolin Li, Xiuhua Guo, Juanhua Su and Kexing Song
The effect of different service parameters on the current-carrying tribological properties of CF-Al2O3/Cu composites was investigated, and the damage behavior of the composites…
Abstract
Purpose
The effect of different service parameters on the current-carrying tribological properties of CF-Al2O3/Cu composites was investigated, and the damage behavior of the composites under different service parameters was probed. The purpose of this study is to provide a theoretical basis for the application of CF-Al2O3/Cu composites.
Design/methodology/approach
The composites were fabricated by internal oxidation combined with powder metallurgy. The current-carrying tribological properties of CF-Al2O3/Cu composites were investigated on an electrical damage test system at different loads and currents.
Findings
As the load increases, the wear mechanism of the composite changes from abrasive wear to delamination wear. As the current increases, the oxidation wear and arc erosion of the composites gradually intensified. Under the service parameters of 0–25 A and 30–40 N, the composite has relatively stable current-carrying tribological properties.
Originality/value
This paper could provide a theoretical basis for the practical application of CF-Al2O3/Cu composites.
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Hoda Sabry Sabry Othman, Salwa H. El-Sabbagh and Galal A. Nawwar
This study aims to investigate the behavior of the green biomass-derived copper (lignin/silica/fatty acids) complex, copper lignin/silica/fatty acids (Cu-LSF) complex, when…
Abstract
Purpose
This study aims to investigate the behavior of the green biomass-derived copper (lignin/silica/fatty acids) complex, copper lignin/silica/fatty acids (Cu-LSF) complex, when incorporated into the nonpolar ethylene propylene diene (EPDFM) rubber matrix, focusing on its reinforcing and antioxidant effect on the resulting EPDM composites.
Design/methodology/approach
The structure of the prepared EPDM composites was confirmed by Fourier-transform infrared spectroscopy, and the dispersion of the additive fillers and antioxidants in the EPDM matrix was investigated using scanning electron microscopy. Also, the rheometric characteristics, mechanical properties, swelling behavior and thermal gravimetric analysis of all the prepared EPDM composites were explored as well.
Findings
Results revealed that the Cu-LSF complex dispersed well in the nonpolar EPDM rubber matrix, in thepresence of coupling system, with enhanced Cu-LSF-rubber interactions and increased cross-linking density, which reflected on the improved rheological and mechanical properties of the resulting EPDM composites. From the various investigations performed in the current study, the authors can suggest 7–11 phr is the optimal effective concentration of Cu-LSF complex loading. Interestingly, EPDM composites containing Cu-LSF complex showed better antiaging performance, thermal stability and fluid resistance, when compared with those containing the commercial antioxidants (2,2,4-trimethyl-1,2-dihydroquinoline and N-isopropyl-N’-phenyl-p-phenylenediamine). These findings are in good agreement with our previous study on polar nitrile butadiene rubber.
Originality/value
The current study suggests the green biomass-derived Cu-LSF complex to be a promising low-cost and environmentally safe alternative filler and antioxidant to the hazardous commercial ones.
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P. Gunasekar, Anderson A. and Praveenkumar T.R.
Composite materials have revolutionized the aerospace industry by offering superior structural qualities over traditional elements. This study aims to focus on the development and…
Abstract
Purpose
Composite materials have revolutionized the aerospace industry by offering superior structural qualities over traditional elements. This study aims to focus on the development and testing of bamboo natural fiber-based composites enhanced with SiO2 nanoparticles.
Design/methodology/approach
The investigation involved fabricating specimens with varying nanoparticle compositions (0, 10 and 20%) and conducting tensile, flexural, impact and fracture toughness tests. Results indicated significant improvements in mechanical properties with the addition of nanoparticles, particularly at a 10% composition level.
Findings
This study underscores the potential of natural fiber composites, highlighting their environmental friendliness, cost-effectiveness and improved structural properties when reinforced with nanoparticles. The findings suggest an optimal ratio for nanoparticle integration, emphasizing the critical role of precise mixing proportions in achieving superior composite performance.
Originality/value
The tensile strength, flexural strength, impact resistance and fracture toughness exhibited notable enhancements compared with the 0 and 20% nanoparticle compositions. The 10% composition showed the most promising outcomes, showcasing increased strength across all parameters.
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Fukang Yang, Wenjun Wang, Yongjie Yan and YuBing Dong
Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to…
Abstract
Purpose
Polyethylene terephthalate (PET) as a fiber molding polymer is widely used in aerospace, electrical and electronic, clothing and other fields. The purpose of this study is to improve the thermal insulation performance of polyethylene terephthalate (PET), the SiO2 aerogel/PET composites slices and fibers were prepared, and the effects of the SiO2 aerogel on the morphology, structure, crystallization property and thermal conductivity of the SiO2 aerogel/PET composites slices and their fibers were systematically investigated.
Design/methodology/approach
The mass ratio of purified terephthalic acid and ethylene glycol was selected as 1:1.5, which was premixed with Sb2O3 and the corresponding mass of SiO2 aerogel, and SiO2 aerogel/PET composites were prepared by direct esterification and in-situ polymerization. The SiO2 aerogel/PET composite fibers were prepared by melt-spinning method.
Findings
The results showed that the SiO2 aerogel was uniformly dispersed in the PET matrix. The thermal insulation coefficient of PET was significantly reduced by the addition of SiO2 aerogel, and the thermal conductivity of the 1.0 Wt.% SiO2 aerogel/PET composites was reduced by 75.74 mW/(m · K) compared to the pure PET. The thermal conductivity of the 0.8 Wt.% SiO2 aerogel/PET composite fiber was reduced by 46.06% compared to the pure PET fiber. The crystallinity and flame-retardant coefficient of the SiO2 aerogel/PET composite fibers showed an increasing trend with the addition of SiO2 aerogel.
Research limitations/implications
The SiO2 aerogel/PET composite slices and their fibers have good thermal insulation properties and exhibit good potential for application in the field of thermal insulation, such as warm clothes. In today’s society where the energy crisis is becoming increasingly serious, improving the thermal insulation performance of PET to reduce energy loss will be of great significance to alleviate the energy crisis.
Originality/value
In this study, SiO2 aerogel/PET composite slices and their fibers were prepared by an in situ polymerization process, which solved the problem of difficult dispersion of nanoparticles in the matrix and the thermal conductivity of PET significantly reduced.
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Ravikantha Prabhu, Sharun Mendonca, Pavana Kumara Bellairu, Rudolf D'Souza and Thirumaleshwara Bhat
This study explores how titanium oxide (TiO2) filler influences the specific wear rate (SWR) in flax fiber-reinforced epoxy composites (FFRCs) through a Taguchi approach. It aims…
Abstract
Purpose
This study explores how titanium oxide (TiO2) filler influences the specific wear rate (SWR) in flax fiber-reinforced epoxy composites (FFRCs) through a Taguchi approach. It aims to boost abrasive wear resistance by incorporating TiO2 filler, promoting sustainable and eco-friendly materials.
Design/methodology/approach
This study fabricates epoxy/flax composites with TiO2 particles (0–8 wt%) using hand layup. Composites were tested for wear following American Society for Testing and Materials (ASTM) G99-05. Statistical analysis used Taguchi design of experiments (DOE), with ANOVA identifying key factors affecting SWR in abrasive sliding conditions.
Findings
The study illuminates how integrating TiO2 filler particles into epoxy/flax composites enhances abrasive wear properties. Statistical analysis of SWR highlights abrasive grit size (grit) as the most influential factor, followed by normal load, wt% of TiO2 and sliding distance. Grit size has the highest effect at 43.78%, and wt% TiO2 filler contributes 15.61% to SWR according to ANOVA. Notably, the Taguchi predictive model closely aligns with experimental results, validating its reliability.
Originality/value
This paper integrates TiO2 filler and flax fibers to form a novel hybrid composite with enhanced tribological properties in epoxy composites. The use of Taguchi DOE and ANOVA offers valuable insights for optimizing control variables, particularly in natural fiber-reinforced composites (NFRCs).
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The purpose of this paper is to explore the geometric parameter difference of the terrace-like structural transfer film under different working parameters [pressure and velocity…
Abstract
Purpose
The purpose of this paper is to explore the geometric parameter difference of the terrace-like structural transfer film under different working parameters [pressure and velocity (PV) values] and filled particle types (three fillers: SiO2, TiO2 and ZnO), and find the geometric parameter related to the wear of polytetrafluoroethylene (PTFE)-based composites.
Design/methodology/approach
PTFE composites were filled with SiO2, TiO2 and ZnO particles, and the morphology parameter of the PTFE composite transfer film under different PV values obtained from the rotary reciprocating pin-on-disk frictional tester was quantified by using a three-dimensional laser scanning microscope.
Findings
The results showed that the effective layer coverage rate and effective thickness of the transfer film had a good relationship with the wear of the three PTFE composites. On the whole, increasing the speed or load was helpful to increase the effective thickness of the three PTFE composite transfer films, but reduced the effective layer coverage rate. The greater the effective layer coverage rate and effective thickness of the transfer film, the better the wear resistance of the PTFE composites in the entire speed and load range.
Originality/value
This work will promote further understanding of the transfer film and lay a foundation for realizing its morphology regulation and improving the wear of the PTFE composites.
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Wei Zhang, Seiji Yamashita, Takeshi Kumazawa, Fumihito Ozeki, Hideki Hyuga and Hideki Kita
This study aims to investigate the friction behavior of SiC-B4C composite ceramics treated by annealing in air sliding against SiC balls.
Abstract
Purpose
This study aims to investigate the friction behavior of SiC-B4C composite ceramics treated by annealing in air sliding against SiC balls.
Design/methodology/approach
The dry sliding tests were performed with a ball-on-disk tribometer in ambient air condition. Analysis of friction coefficient, phase compositions of the surfaces, morphologies of worn surfaces of disks and wear scars of balls and surface profiles of wear tracks for disks were carried out using Raman spectroscope, microscope and surface profilometer.
Findings
The results show that a self-lubricating layer with the main composition of H3BO3 was successfully fabricated on the surface of SiC-B4C composite ceramics by the annealing treatment in air. When the mass fraction of SiC is more than that of B4C, SiC-B4C composite ceramics show higher friction coefficients, the values of which are 0.38 for 80 Wt.%SiC-20 Wt.%B4C and 0.72 for 60 Wt.%SiC-40 Wt.%B4C, respectively. SiC-B4C composite ceramics show lower friction coefficients when the mass fraction of B4C is more than that of SiC. The low friction coefficients of 40 Wt.%SiC-60 Wt.% B4C composite ceramics (0.16) and 20 Wt.%SiC-80 Wt.% B4C composite ceramics (0.20) are attributed to the formation of a sufficient amount of H3BO3 layer, rather than the layer of silicon oxides.
Originality/value
This study will help to understand the friction behavior of SiC-B4C composite ceramics with different ratios of SiC to B4C treated by annealing in air.
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Muhammet Çağrı Ayan, Serap Kiriş, Ahmet Yapici, Muharrem Karaaslan, Oğuzhan Akgöl, Olcay Altıntaş and Emin Ünal
The purpose of this paper is to investigate cotton fabric behavior that is exposed to radar waves between selected operation frequencies as an alternative radar-absorbing material…
Abstract
Purpose
The purpose of this paper is to investigate cotton fabric behavior that is exposed to radar waves between selected operation frequencies as an alternative radar-absorbing material (RAM) response. Cotton fabric biocomposite materials were compared with carbon fabric composite materials, which are good absorbers, in terms of mechanical and electromagnetic (EM) properties for that purpose.
Design/methodology/approach
The laminated composite plates were manufactured by using a vacuum infusion process. The EM tests were experimentally performed with a vector network analyzer to measure reflection, transmission and absorption ability of cotton fabric, carbon fabric and cotton–carbon fabric (side by side) composite plates between 3 and 18 GHz. The tensile and low-velocity impact tests were carried out to compare the mechanical properties of cotton fabric and carbon fabric composite plates. A scanning electron microscope was used for viewing the topographical features of fracture surfaces.
Findings
The cotton fabric composite plate exhibits low mechanical values, but it gives higher EM wave absorption values than the carbon fabric composite plate in certain frequency ranges. Comparing the EM absorption properties of the combination of cotton and carbon composites with those of the carbon composite alone, it appears that the cotton–carbon combination can be considered as a better absorber than the carbon composite in a frequency range from 12 to 18 GHz at Ku band.
Originality/value
This paper shows how cotton, which is a natural and easily supplied low-cost raw material, can be evaluated as a RAM.
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Zhen Pan and Fenglian Sun
The purpose of this paper is to design a novel die-attach composite joint for high-temperature die-attach applications based on transient liquid phase bonding. Moreover, the…
Abstract
Purpose
The purpose of this paper is to design a novel die-attach composite joint for high-temperature die-attach applications based on transient liquid phase bonding. Moreover, the microstructure, shear strength, electrical property, thermal conductivity and aging property of the composite joint were investigated.
Design/methodology/approach
The composite joint was made of microporous copper and Cu3Sn. Microporous copper was immersed into liquid Sn to achieve Sn-microporous copper composite structure for die attachment. By the thermo-compression bonding, the Cu3Sn-microporous copper composite joint with a thickness of 100 µm was successfully obtained after bonding at 350 °C for 5 min under a low pressure of 0.6 MPa.
Findings
After thermo-compression bonding, the resulting interconnection could withstand a high temperature of at most 676 °C, with the entire Sn transforming into Cu3Sn with high remelting temperatures. A large shear strength could be achieved with the Cu3Sn-microporous copper in the interconnections. The formed bondlines demonstrated a good electrical and thermal conductivity owing to the large existing amount of copper in the interconnections. Furthermore, the interconnection also exhibited excellent reliability under high temperature aging at 300 °C.
Originality/value
This die-attach composite joint was suitable for power devices operating under high temperatures or other harsh environments.
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