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1
Swiderski. "CFRP Non-Destructive Testing Using IR Thermography Methods." Proceedings 27, no. 1 (September 25, 2019): 30. http://dx.doi.org/10.3390/proceedings2019027030.
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Multilayer composites reinforced fibres are often used in military applications as construction materials for lightweight ballistic covers that protect against fragments and projectiles. The basic fibre used in these applications is aramid fibre, but research is also conducted using carbon fibres. One of the many methods used in non-destructive testing of composites is active infrared thermography, in which different types of sources can be used to thermally stimulate the material being tested. This paper compares the results obtained with various methods of thermal stimulation in the study of samples made with CFRP with deliberately introduced defects and destructive tests.
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Hyie, Koay Mei, Noor Haznida Bakar, Ridzuan Jazlan, A. Jumahat, and Anizah Kalam. "The Compressive Properties of Kevlar/Kenaf Hybrid Composites." Applied Mechanics and Materials 763 (May 2015): 19–24. http://dx.doi.org/10.4028/www.scientific.net/amm.763.19.
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Natural fibres are aimed to replace or at least to reduce the dependence of the industrial sector against low degradability of raw material. Hence, this study is performed to investigate the effect of stacking sequence and fibre orientation on the compressive properties of Kevlar/kenaf hybrid composites. Previous study suggested that treated kenaf fibres improved the fibre’s properties. Therefore, kenaf fibres was treated with NaOH of 6% concentration for 12 hours before rinsed and dried to be used in this study. The stacking sequence was varied for different weight percentage of woven Kevlar from 0 wt% to 23 wt%, while the kenaf fibres were arranged at 0° and 90° orientation, respectively. The compressive properties of the Kevlar/kenaf fibre hybrid composites were investigated using Instron Universal Testing Machine (ASTM standard D3410M). Stereo-zoom was used to identify the fibre orientation and the bonding between the fibres and matrix. For stacking sequence, the study showed that the arrangement of kenaf fibres on the middle part, “sandwiched” between Kevlar on the outer part, gave the best compressive performance. The sample in 0° orientation exhibited better compressive strength and modulus than 90° orientation. The outcome of this research has shown significant increase of compressive strength with the addition of kenaf fibre replacing the Kevlar.
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Shalwan, A., S. Oraby, and A. Alaskari. "Mathematical Modelling of the Interfacial Adhesion of Date Palm/Epoxy." Journal of Materials Science Research 5, no. 3 (April 20, 2016): 29. http://dx.doi.org/10.5539/jmsr.v5n3p29.
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<p class="1Body">In recent years, high interests has emerged to use natural fibres as alternative reinforcements synthetic due to its unique benefits regarding renewability, recyclability, degradability, lightweight, and low cost. Recent investigations revealed that the mechanical performance of fibre reinforced polymer composites (FRPCs) is predicated mainly on the interfacial adhesion of fibre with the matrices. In the current work, an empirical approach was exploited to develop mathematical models using linear regression routines available in SPSS IBM program. Such models are established to determine the functional interrelations between, each of the fibres diameters and the percentage of chemical treatment, as independent or response variables, and the interfacial bonding between the DPF and Epoxy resin. Both single fibre tensile testing (SFTT) and single fibre fragmentation testing (SFFT) are considered to study the interfacial adhesion of fibre with matrix and to reflect the real loading conditions. Such testing procedures are carried out for Date Palm Fibres (DPFs) and Date palm fibre reinforced Epoxy composites (DPFEs) with different fibre diameter (0.3-0.7 mm) under different NaOH concentrations (0-9 wt.%). Experimental testing results indicated that the optimum interfacial adhesion and strength of the fibre can be achieved with small fibre diameter when 6 wt. % NaOH concentrations is employed. The use of higher NaOH concentration generally leads to deterioration in the fibre strength. Developed models, on one hand, proved to have the capability to qualitatively and quantitatively grasp the true relationships and, on the other hand, to emphasize the high potential to utilize natural fibres as a replacement of synthetic fibres with affirmation taking into consideration the role of diameter size and chemical treatment of fibres to reach the optimum mechanical behaviour of NFRPCs.</p>
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Fládr, Josef, and Iva Broukalová. "Testing the Long-Term Flexural Behaviour of FRC with Synthetic Fibres." Advanced Materials Research 1106 (June 2015): 136–39. http://dx.doi.org/10.4028/www.scientific.net/amr.1106.136.
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The paper describes a new methodology of investigation of long-term behaviour of fibre reinforced concrete (FRC) with of synthetic fibres. A set of tests was manufactured from FRC with synthetic fibres commonly used for production of FRC and referential set from SFRC (steel fibre reinforced concrete) and subjected to long-term loading. The testing is based on three-point flexural loading. In given time intervals deflections are measured and recorded. Results of investigations are presented and discussed.
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Adusumalli, Ramesh Babu, Karthik Chethan Venkateshan, Chandrakala Kunchi, and Surya R. Vadlamani. "Tensile testing of single fibres." Procedia Structural Integrity 14 (2019): 150–57. http://dx.doi.org/10.1016/j.prostr.2019.05.020.
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Künzel, Karel, Václav Papež, Kristýna Carrera, Petr Konrád, Michal Mára, Přemysl Kheml, and Radoslav Sovják. "Electromagnetic Properties of Steel Fibres for Use in Cementitious Composites, Fibre Detection and Non-Destructive Testing." Materials 14, no. 9 (April 22, 2021): 2131. http://dx.doi.org/10.3390/ma14092131.
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This paper deals with the description, measurement, and use of electromagnetic properties of ferromagnetic fibres used as dispersed fibre reinforcement in composite mixtures. Firstly, the fibres’ magnetic properties are shown, and a method of measuring the hysteresis loop of fibres is proposed. The results from the measurements are presented and a discussion of the influence of measured parameters on the fibres’ orientation in a magnetic field is performed. Furthermore, methods of non-destructive estimation, of their amount and orientation in the composite specimens, are discussed. The main experimental goal of this paper is to show the relationship between this non-destructive method’s results and the destructive flexural strength measurements. The method is sensitive enough to provide information related to fibre reinforcement.
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Kuclourya, Tanay, Mohit Kumar Jain, Shubham Mudliar, and Narendiranath Babu Thamba. "Statistical analysis and investigation of tensile test data of coir composites reinforced with graphene, epoxy and carbon fibre." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 10 (July 15, 2020): 1343–54. http://dx.doi.org/10.1177/1464420720939998.
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A successful attempt has been made to develop coir fibre composites reinforced with graphene, epoxy and carbon fibre. The carbon fibres were arranged in an intercalated manner, which is similar to the coir fibres. The percentage composition of graphene was varied as 1, 2, 4 and 6% by weight of the holding matrix. Suitable surface modifications were done by treating natural fibres by 5% NaOH and 0.3% KMnO4 for better adhesion of fibre and epoxy resin. Sonication and cetyl trimethyl ammonium bromide treatments were also done to achieve the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were made as per D638 American Society for Testing and Materials (ASTM) standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. Tensile testing was carried out to determine the mechanical properties of the composites. Two-way analysis of variance was used as a statistical tool to find the effect of parameters such as ‘Percentage composition of graphene’ and ‘Type of mould’ on the modulus of the composites. Fourier transform infrared spectroscopy was conducted to determine the interferential adhesion and homogeneous distribution of fibres in the composite matrix. At last, field emission scanning electron microscopy analyses were also done to the specimens before and after tensile testing to determine the morphology of different entities present in the composites.
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Schledjewski, Ralf, Luisa Medina, and Alois K. Schlarb. "Mechanical and Morphological Characterization of Selected Natural Fibres." Advanced Composites Letters 15, no. 2 (March 2006): 096369350601500. http://dx.doi.org/10.1177/096369350601500202.
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The present work aims to characterize the morphological and mechanical properties of hemp and kenaf fibres. The mechanical properties of natural fibres highly depend on many factors like soil, growth conditions, harvest time or fibre treatment. Since the mechanical properties of the composite are highly conditioned by the characteristics of the fibres, a comprehensive study of the mechanical properties of the fibres is required in order to optimize the composite's properties. The fibres were characterized by single fibre tensile testing. Due to the high standard deviation of the measurements, the tensile strength data were statistically assessed. To describe strength data the Weibull distribution function was used. It has been assumed that the fracture stresses of natural fibres are distributed according to the two-parametric Weibull distribution.
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Islam, Faisal, Sébastien Joannès, Steve Bucknell, Yann Leray, Anthony Bunsell, and Lucien Laiarinandrasana. "Investigation of tensile strength and dimensional variation of T700 carbon fibres using an improved experimental setup." Journal of Reinforced Plastics and Composites 39, no. 3-4 (September 24, 2019): 144–62. http://dx.doi.org/10.1177/0731684419873712.
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Knowledge of fibre strength is crucial for understanding the failure behaviour of fibre-reinforced composite materials and structures. Measuring the properties of technical fibres has been known to be very challenging, and the different challenges associated with single fibre characterisation are illustrated in this article. An improved and automated experimental methodology for tensile testing of single fibres is described. This process has been used to generate fibre strength data for T700 carbon fibres at three different gauge lengths of 4, 20 and 30 mm. The variability in strength and modulus of short fibres was found to be much larger than that of longer fibres. Statistical analysis of this large data set has also highlighted the limitations of the standard Weibull distribution for representing fibre strength behaviour. The need for a better statistical representation of the fibre strength data in order to provide a more accurate description of the fibre strength behaviour has been emphasized.
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Drdlová, Martina, Oldřich Sviták, and Vladan Prachař. "Slurry Infiltrated Fibre Concrete with Waste Steel Fibres from Tires - The Behaviour under Static and Dynamic Load." Materials Science Forum 908 (October 2017): 76–82. http://dx.doi.org/10.4028/www.scientific.net/msf.908.76.
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Waste fibres coming from the recycling process of the old tires were incorporated in slurry infiltrated fibre concrete (SIFCON), which is a special type of high performance fibre reinforced concrete with high fibre content. The technological feasibility (i.e. suitability of the waste fibres for SIFCON technology) was assessed using infiltration test and homogeneity test. Test specimens were prepared with three volume fractions (5; 7.5 and 10% by vol.) of waste unclassified fibres. SIFCON with industrial steel fibres (10% by vol.) and high performance fibre concrete with industrial fibres were also cast and tested for comparison purposes. Quasi-static mechanical properties were determined. The impact test was carried out by using an in-house manufactured impact testing machine based on drop test principle. Realized tests confirmed the possibility of using the waste fibres for SIFCON technology. The obtained results indicate, that the usage of waste fibres does not significantly reduce the values of SIFCON flexural and compressive strength at quasi-static load and energy absorption at dynamic load, the values were comparable to the specimens with industrially produced fibres. With increasing fibre content, the mechanical parameters and energy-absorption characteristics at dynamic load are increasing as well.
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Ilankeeran, Prasanna Kumar, Preetamkumar M. Mohite, and Sudhir Kamle. "Axial Tensile Testing of Single Fibres." Modern Mechanical Engineering 02, no. 04 (2012): 151–56. http://dx.doi.org/10.4236/mme.2012.24020.
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Wilson, D. K. "MONITORING AND TESTING OF MANUFACTURED FIBRES." Textile Progress 28, no. 2 (September 1998): 1–35. http://dx.doi.org/10.1080/00405169808688873.
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Balakrishnan, Subashini, GL Dharmasri Wickramasinghe, and UG Samudrika Wijayapala. "A novel approach for banana (Musa) Pseudo-stem fibre grading Method: Extracted fibres from Sri Lankan Banana Cultivars." Journal of Engineered Fibers and Fabrics 15 (January 2020): 155892502097176. http://dx.doi.org/10.1177/1558925020971766.
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Fibre grading systems are recognized as essential for both customers and the manufacturers of natural fibres. Identification or grading of fibre content in textiles and fibre industry has become extremely challenging even for experienced parties in the field. The increasing variety of fibres and blending techniques are the reason for this. Consequently, laboratory tests are very important for grading and verification. This research focuses on observing the surface structure of the banana pseudostem fibre in the light microscope, scanning electron microscope, fineness, strength, chemical solubility, burning behaviours, and grading for different banana varieties. Fibres and fibre bundles were inspected visually and tested. One of the focus of this research is to produce quantifiable observations such as general observation test and feeling test. So the quantitative method can lead to exploring the systemic connection between experimental observation and mathematical expression for the grading of banana fibres. Based on the testing results, a novel grading system was introduced for banana fibres varieties (Sri Lankan cultivar).
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Das, Pallab, and S. Choudhury. "Experimental Study on Fibre-Reinforced Concrete Beam-Column Joint with Ductile Detailing Under Reverse Cyclic Loading." International Journal of Engineering & Technology 7, no. 3.16 (July 26, 2018): 85. http://dx.doi.org/10.14419/ijet.v7i3.4.16189.
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The behaviour of a beam-column (BC) joint in a moment resisting framed structure is the key criteria when the structure is subjected to seismic loading. In the past many research have been carried out to grasp the mechanism of failure of beam-column joint and methods to enhance the performance of beam-column joint have been developed. The provision of ductile detailing as prescribed in IS-13920: 1993 has been followed. Improvement of the performance of joint region has been studied by using additional reinforcement with different fibres. In the present study the performance of the BC joint is studied in terms of load vs. displacement curve, stiffness degradation vs. drift angle curve and energy dissipation by the BC joint using different types of fibres in the specimen. The laboratory testing of the concrete cubes and cylinders reinforced with different percentages of fibre volume have been implemented. Based on the test results, the selection of the optimum quantity of fibre that can be used in beam-column joint for each type of fibre has been done. The testing of the specimens of BC joints is carried out in cyclic actuator of capacity 100 kN. The fibres which have been used in the present study are carbon fibre, steel fibre and glass fibre. Percentages of the fibres that had been added to the specimen are carbon fibre (0.75%), steel fibre (0.75%) and glass fibre (0.50%) respectively and the control specimen made from ordinary concrete made of M25 mix concrete. The performance of the specimens reinforced with different type of fibres is then compared and the specimen showing desirable performance under cyclic loading is found out. It has been observed that the application of carbon fibres could improve the strength and ductility of BC joints appreciably.
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Komárková, Tereza. "Design of Methodology for Non-Destructive Testing of Steel-Reinforced-Fiber-Concrete." Key Engineering Materials 714 (September 2016): 179–85. http://dx.doi.org/10.4028/www.scientific.net/kem.714.179.
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Measuring instruments used for non-destructive testing of structures thanks to advances in electronics and electrical engineering are still more frequently applied. Among the building materials with which the ability to perform quality control using non-destructive testing methods would be most welcome is indisputably steel reinforced fibre concrete (SFRC). The paper deals with the design of new methods and methodologies that enable determination of the concentration and orientation of steel fibres in steel fibre reinforced concrete. Especially the distribution of steel fibres in concrete is the quintessential aspect of this construction material. Initial results of experiments have demonstrated the applicability of the proposed methods and methodologies and the objective of the article is to introduce it to the scientific community.
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Kamps, Jan Henk, Luke Henderson, Christina Scheffler, Ruud van der Heijden, Frank Simon, Teena Bonizzi, and Nikhil Verghese. "Electrolytic Surface Treatment for Improved Adhesion between Carbon Fibre and Polycarbonate." Materials 11, no. 11 (November 12, 2018): 2253. http://dx.doi.org/10.3390/ma11112253.
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To achieve good mechanical properties of carbon fibre-reinforced polycarbonate composites, the fibre-matrix adhesion must be dialled to an optimum level. The electrolytic surface treatment of carbon fibres during their production is one of the possible means of adapting the surface characteristics of the fibres. The production of a range of tailored fibres with varying surface treatments (adjusting the current, potential, and conductivity) was followed by contact angle, inverse gas chromatography and X-ray photoelectron spectroscopy measurements, which revealed a significant increase in polarity and hydroxyl, carboxyl, and nitrile groups on the fibre surface. Accordingly, an increase in the fibre-matrix interaction indicated by a higher interfacial shear strength was observed with the single fibre pull-out force-displacement curves. The statistical analysis identified the correlation between the process settings, fibre surface characteristics, and the performance of the fibres during single fibre pull-out testing.
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Hao, Yi Fei, Hong Hao, and Gang Chen. "Experimental Tests of Steel Fibre Reinforced Concrete Beams under Drop-Weight Impacts." Key Engineering Materials 626 (August 2014): 311–16. http://dx.doi.org/10.4028/www.scientific.net/kem.626.311.
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Concrete is a brittle material, especially under tension. Intensive researches have been reported to add various types of fibres into concrete mix to increase its ductility. Recently, the authors proposed a new type of steel fibre with spiral shape to reinforce concrete material. Laboratory tests on concrete cylinder specimens demonstrated that compared to other fibre types such as the hooked-end, deformed and corrugated fibres the new fibres have larger displacement capacity and provide better bonding with the concrete. This study performs drop-weight impact tests to investigate the behaviour of concrete beams reinforced by different types of steel fibres. The quasi-static compressive and split tensile tests were also conducted to obtain the static properties of plain concrete and steel fibre reinforced concrete (FRC) materials. The quasi-static tests were carried out using hydraulic testing machine and the impact tests were conducted using an instrumented drop-weight testing system. Plain concrete and concrete reinforced by the commonly used hooked-end steel fibres and the proposed spiral-shaped steel fibres were tested in this study. The volume dosage of 1% fibre was used to prepare all FRC specimens. Repeated drop-weight impacts were applied to the beam specimens until total collapse. A 15.2 kg hard steel was used as the drop-weight impactor. A drop height of 0.5 m was considered in performing the impact tests. The force-displacement relations and the energy absorption capabilities of plain concrete and FRC beams were obtained, compared and discussed. The advantage and effectiveness of the newly proposed spiral-shaped steel fibres in increasing the performance of FRC beam elements under impact loads were examined.
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Erliawan, Gusti Alvin, and Muhammad Firdaus. "STABILISASI TANAH DENGAN MENGGUNAKAN PASIR DAN ABU SERABUT KELAPA TERHADAP NILAI CBR." Jurnal Gradasi Teknik Sipil 3, no. 2 (December 2, 2019): 31–35. http://dx.doi.org/10.31961/gradasi.v3i2.798.
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Land is a very important basic material in a construction, because basically the soil serves as the object of all types of konstruki and as a base they saw on a structure must have the nature and power of a good support, ground the sand mixture is stabilized with 10% coconut fibres 1% ash, sand mix 10% ash 3% coconut fibers, sand mix 10% coconut fibres 5% ash.
Research done in the laboratory of Geotechnical and Civil Engineering Transfortasi State Polytechnic Banjarmasin, testing is done at the programme LEVEL include: Testing water content in accordance with SNI 03-1965-2008, Heavy Type Testing in accordance with SNI 03-1964-2008, testing the limits of Liquid in accordance with SNI 03-1967-2008, testing the limits of Plastis accordance with SNI 03-1966-2008, Compaction Testing in accordance with STANDARD 03-1743-2008, and California Bearing Ratio Testing in accordance with STANDARD 03-1744-2012.
From the results obtained by testing the value of the physical properties and mechanical ground on mixed 0%: 69.15% w, Gs 2.505, LL 49.50%, PL 31.64%, PI 13.61% 27.5% opt, w, Y d max 1.268 Gr/Cm3, CBR design 3.1%. From the results obtained by testing the value of the physical properties and mechanical Sand mixture soil at 10% Coconut Fibres 1% Ash: Gs (combined), 2.369 LL 49.55%, PL 33.18% PI, 16.37%, w opt 35.25%, Yd max 1.178 Gr/Cm3, CBR design of 6.8%. From the results obtained by testing the value of the physical properties and mechanical ground on mixed Sand Ash 10% 3% Coconut Fibres: Gs (combined), 2.369 LL 49.50%, PL 34.08% PI, 15.42%, w opt 25.50%, Yd max 1.205 Gr/Cm3, CBR design of 7.3%. From the results obtained by testing the value of the physical properties and mechanical Sand mixture soil at 10% Coconut Fibres 5% Grey: Gs (combined) 2.668, LL 49.40%, PL 35.79%, 13.61% PI, w opt 20.45%, Yd max 1.315 Gr/Cm3, CBR design 8.0%.
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Hengstermann, Martin, Karl Kopelmann, Andreas Nocke, Anwar Abdkader, and Chokri Cherif. "Development of a new hybrid yarn construction from recycled carbon fibres for high-performance composites: Part IV: Measurement of recycled carbon fibre length." Journal of Engineered Fibers and Fabrics 15 (January 2020): 155892502091072. http://dx.doi.org/10.1177/1558925020910729.
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Due to the increasing application of carbon fibre–reinforced plastics, the use of recycled carbon fibres can help reduce the tremendous amount of carbon fibre waste growing worldwide. In this context, the processing of longer recycled carbon fibres (>40 mm mean length) into hybrid yarn constructions offers a promising solution. The characterisation of recycled carbon fibre length is essential for textile processes. However, to suit the atypical fibre characteristics of recycled carbon fibres compared to standard natural or man-made-fibres, the development of an adequate measuring technique is required. Investigations on the state of the art suggest that an adapted fibrograph method might pose an appropriate measuring system. Therefore, new test equipment and an alternative image analysing method based on pixel greyscale values were developed. To enable a calibration process, different samples with cut carbon fibre from carded and drafted slivers were intensively tested and compared. In addition, an adapted reference method was investigated by combining single fibre measurement and image processing techniques. In a final step, recycled carbon fibres samples with unknown fibre length were tested. Results proved that the presented measuring system is adequate for the testing of longer recycled carbon fibres in webs or slivers. All measured values were close to the measured reference length values (deviation ±4%).
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Munawar, Rose Farahiyan, Nurul Hayati Jamil, Mohd Khairul Shahril, Skh Muhammad Skh Abdul Rahim, Muhammad Zaimi Zainal Abidin, M. A. Azam, and Kok Tee Lau. "Development of Green Composite: Pineapple Leaf Fibers (PALF) Reinforced Polylactide (PLA)." Applied Mechanics and Materials 761 (May 2015): 520–25. http://dx.doi.org/10.4028/www.scientific.net/amm.761.520.
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Green composite material has become the most desired material to replace polymer composites made from fossil oil. Besides having advantages over its biodegradability and quality performances, the material sources are abundant and renewable. Therefore, this research focused on developing green composite which is derived from a combination of pineapple leaf fibers (PALF) and Polylactide (PLA). PALF is extracted from pineapple leaves which are easily found during harvesting pineapple plantation. In order to study the influences of different fibres characterization, the fibres were extracted from different types of pineapple available in Malaysia, namely Moris Gajah, Jasopine, Maspine, and N36. The main objective of this study was to investigate the physical and mechanical properties of this green composite. The physical testing was carried out to determine water absorption while the tensile and bending tests were conducted for mechanical testing. For the purpose of comparing the material properties, PALF reinforced polypropelene (PP) was developed too. Based on the result, Jasopine fibre shows the highest tensile and flexural strength for the combination of both polymers in comparison to the other types of PALF.
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Islam, Faisal, Sébastien Joannès, and Lucien Laiarinandrasana. "Evaluation of Critical Parameters in Tensile Strength Measurement of Single Fibres." Journal of Composites Science 3, no. 3 (July 9, 2019): 69. http://dx.doi.org/10.3390/jcs3030069.
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Mechanical properties of fibre reinforced composites are primarily dependent on those of fibres. Fibre properties are used for estimating the damage and strength behaviour of composite materials and structures. Tensile strength of fibres is commonly determined by single fibre tensile tests, which is challenging and is prone to measurement errors. In this study, different possible sources of errors due to experimental limitations in the fibre testing process were identified. Their effect on fibre tensile strength was analytically modelled. This model was used to evaluate the uncertainty in experimentally determined fibre strength. A sensitivity analysis was conducted to rank the relative significance of input quantities on the calculated fibre strength. Since composite models require fibre properties determined at very small gauge lengths, the results of the sensitivity analysis were extrapolated to determine critical parameters for tests done at those small gauge lengths of a few millimetres. It was shown that, for sufficiently long fibres, their strength depends mainly on the diameter and failure force; however, for shorter gauge lengths, the effects of misalignment become very significant. The knowledge of uncertainty would be useful in estimating the reliability of the predictions made by composite strength models on the damage and failure behaviour of composite materials and structures. Minimising the influence of critical parameters on fibre strength would help in designing improved single fibre testing systems capable of determining fibre strength more accurately.
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Everitt, Nicola M., Nesma T. Aboulkhair, and Mike J. Clifford. "Looking for Links between Natural Fibres’ Structures and Their Physical Properties." Conference Papers in Materials Science 2013 (November 6, 2013): 1–10. http://dx.doi.org/10.1155/2013/141204.
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Natural fibres have excited growing attention in the last decade since they offer the potential to act as candidates substituting for man-made fibres as composite reinforcements. Their superiority over synthetic fibres is that they are environmentally friendly and biodegradable. Numerous industrial sectors are interested in such composites, including but to name a few the aeronautical and the automotive fields. However natural fibres tend to suffer from large variability in properties compared to the “traditional” man-made fibres, and the performance of their composites often does not conform to that theoretically predicted from single-fibre tests. This study investigates the properties of the single fibres. The mechanical properties of the fibres were correlated to their microstructure. There are factors that were found to contribute to the reported variability, some of which are inherent in the fibres and some are related to testing parameters.
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Suresh, Harsha, Vincent Ho, and Jerry Zhou. "Rheological Characteristics of Soluble Fibres during Chemically Simulated Digestion and their Suitability for Gastroparesis Patients." Nutrients 12, no. 8 (August 17, 2020): 2479. http://dx.doi.org/10.3390/nu12082479.
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Dietary fibres are an integral part of a balanced diet. Consumption of a high-fibre diet confers many physiological and metabolic benefits. However, fibre is generally avoided by individuals with gastrointestinal motility disorders like gastroparesis due to increased likelihood of exacerbated symptoms. Low-viscosity soluble fibres have been identified as a possible source of fibre tolerable for these individuals. The aim of this study is to determine the rheological properties of 10 common commercially available soluble fibres in chemically simulated digestive conditions and evaluate their suitability for individuals with mild to moderate gastroparesis, a gastric motility disorder. Rheological testing under neutral condition (distilled water pH 7) and chemically simulated gastric digestion were evaluated to determine the yield point and relative viscosity of each fibre. Our results reveal two rheological categories of soluble fibres; pseudoplastic and dilatant. Simulated digestion was shown to significantly alter the yield-points of psyllium husk, iota-carrageenan, beta-glucan, apple-fibre pectin, and inulin. Gum Arabic and partially hydrolysed guar gum showed the lowest viscosities and were not affected under simulated digestion, characteristics that make them potential candidate fibres for patients with gastroparesis. Altogether, our results demonstrate that digestion can have a significant impact on fibre viscosity and should be taken into consideration when evaluating the suitability of fibres for patients with gastric motility disorders.
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Ravindran, S., N. Mani, M. Kannan, S. Santhosh, and R. Kamal. "Wear testing of polypropylene termina chebula fibres." IOP Conference Series: Materials Science and Engineering 912 (September 12, 2020): 052024. http://dx.doi.org/10.1088/1757-899x/912/5/052024.
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Glovinová, E., M. Kučera, and J. Pavel. "Testing hazardous asbestos fibres in animal tissues." Toxicological & Environmental Chemistry 43, no. 1-2 (April 1994): 13–17. http://dx.doi.org/10.1080/02772249409358013.
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LINDLEY, F. W. "Testing and Analysis of Fibres and Finishes." Journal of the Society of Dyers and Colourists 81, no. 5 (October 22, 2008): 206–9. http://dx.doi.org/10.1111/j.1478-4408.1965.tb02660.x.
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Adusumalli, Ramesh-Babu, Ulrich Müller, Hedda Weber, Thomas Roeder, Herbert Sixta, and Wolfgang Gindl. "Tensile Testing of Single Regenerated Cellulose Fibres." Macromolecular Symposia 244, no. 1 (December 2006): 83–88. http://dx.doi.org/10.1002/masy.200651207.
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Palanivel, S., and M. Sekar. "Experimental and Numerical Investigation on Stress-Strain Relationships of GFRP and Lateral Ties Confined Polyolefin Fibre Reinforced Concrete under Monotonic Axial Compression." Applied Mechanics and Materials 253-255 (December 2012): 466–73. http://dx.doi.org/10.4028/www.scientific.net/amm.253-255.466.
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In this investigation, the combined confinement effect of spacing of lateral ties, volume fraction of polyolefin fibres and fibre reinforced polymer(FRP) wraps was studied both experimentally and analytically from the point of deformability characteristics of concrete for seismic resistance. Low modulus synthetic fibers such as polyolefin based fibers, it is shown that polyolefin fibers with sufficient tensile strength can successfully enhance the mechanical properties of concrete. The mechanism of delaying and arresting the progressive internal cracking by the fibres can be made use in passive confinement of concrete. In this study the confinement effectiveness of GFRP wraps of single and double layer and polyolefin fibres of volume fractions 0.7% and 0.9% in addition to lateral ties of spacing 145mm and 75mm on concrete prisms of size 150 ×150 ×300 mm were investigated. Such concrete is termed as FRP confined fiber reinforced concrete(FRPCFRC).This paper presents an analytical model(profile) for predicting the constitutive behaviour of FRPCFRC based on the experimental and analytical results. A total of thirty nine prisms of size 150 ×150 ×300 mm were cast and tested under strain control rate of loading. The results of the testing demonstrate the behavioral differences between FRP confined concrete and FRP confined FRC and the ability of the synthetic macro fiber to be used as secondary reinforcement in performance based seismic resistance applications.
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Lakusic, Stjepan. "Mechanical flexural properties of concrete with melt-extract stainless steel fibres." Journal of the Croatian Association of Civil Engineers 72, no. 12 (January 2021): 1155–64. http://dx.doi.org/10.14256/jce.2992.2020.
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An experimental study is performed to evaluate the effect of melt-extract stainless steel fibres on mechanical and flexural properties of concrete. A total of seventy-two specimens are used to determine an optimum fibre dosage and mechanical properties of plain and steel fibre reinforced concrete. Twelve full-scale beam specimens are then exposed to four-point bending tests. The effect of melt-extract stainless steel fibres on flexural behaviour of beams is quantified in this testing. A beam specimen is exposed to four-point bending, after being subjected to 15000 cycles of fatigue load. Pre- and post-fatigue flexural properties of beams with melt-extract steel fibres are compared and discussed.
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Lakusic, Stjepan. "Mechanical flexural properties of concrete with melt-extract stainless steel fibres." Journal of the Croatian Association of Civil Engineers 72, no. 12 (January 2021): 1155–64. http://dx.doi.org/10.14256/jce.2992.2020.
Full textAbstract:
An experimental study is performed to evaluate the effect of melt-extract stainless steel fibres on mechanical and flexural properties of concrete. A total of seventy-two specimens are used to determine an optimum fibre dosage and mechanical properties of plain and steel fibre reinforced concrete. Twelve full-scale beam specimens are then exposed to four-point bending tests. The effect of melt-extract stainless steel fibres on flexural behaviour of beams is quantified in this testing. A beam specimen is exposed to four-point bending, after being subjected to 15000 cycles of fatigue load. Pre- and post-fatigue flexural properties of beams with melt-extract steel fibres are compared and discussed.
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Hippeli, Susanne, Kerstin Dornisch, Thorsten Wiethege, Adrian Gillissen, Klaus-Michael Müller, and Erich F. Elstner. "Biological Durability and Oxidative Potential of Man-Made Vitreous Fibres as Compared to Crocidolite Asbestos Fibres." Zeitschrift für Naturforschung C 56, no. 7-8 (August 1, 2001): 633–48. http://dx.doi.org/10.1515/znc-2001-7-825.
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In this study we investigated relationships between redox properties and biodurability of crocidolite asbestos fibres and three different man-made vitreous fibres (MMVF): traditional stone wool fibres (MMVF 21), glass fibres (MMVF 11) and refractory ceramic fibres (RCF). Each fibre type was incubated up to 22 weeks in four different incubation media: gamble solution (GS) pH 5.0 and pH 7.4, representing blood plasma without proteins, and surfactant like solution (SLS) pH 5.0 and pH 7.4. During incubation time aliquots of incubation mixtures were removed and analysed in a biochemical model reaction, mimicking activated phagocytes. In addition, changes of fibre morphology and chemical composition were examined using SEM-and EDX-technology.In the presence of crocidolite asbestos fibres and MMVF 21 the formation of OH-radicals according to the Haber-Weiss sequence could be demonstrated, whereas MMVF 11 and RCF showed no reactivity. Crocidolite asbestos fibres exhibited a significant higher activity compared with the stone wool fibres at the onset of incubation. The oxidative capacities of these fibre types were shown to depend on both specific surface area and iron content. The oxidative potentials of crocidolite asbestos fibres as well as MMVF 21 were not constant during incubation over several weeks in each incubation medium. The reactivities showed sinoidal curves including reactivities much higher than those at the onset of incubation time. These irregular changes of oxidative capacity may be explained by changes of the redox state of fibre surface-complexed iron.Furthermore our results showed clear differences between incubation of fibres in GS and SLS, respectively, indicating that phospholipids play an important part in fibre dissolution behaviour and oxidative reactivity.In conclusion we suggest, that biodurability testing procedures should not exclusively concentrate on dissolution rates of fibres. They should include fibre characteristics concerning known pathogenic mechanisms to evaluate the real toxic potential of the fibre type looking at. Secondly we suggest, that phospholipids should be constituents of incubation liquids used for standardised fibre biodurability test procedures thus representing more realistic incubation conditions
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Boulanghien, M., M. R’Mili, G. Bernhart, F. Berthet, and Y. Soudais. "Mechanical Characterization of Carbon Fibres Recycled by Steam Thermolysis: A Statistical Approach." Advances in Materials Science and Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/8630232.
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The recent development of technologies for recycling carbon fibre reinforced plastics (CFRPs) leads to the need to evaluate the mechanical response of recycled carbon fibres. As these fibres are likely to be degraded during the recycling treatment, it is very important to determine their tensile residual properties so as to evaluate their ability as reinforcement for new composite materials. Carbon fibres reclaimed by a steam-thermal treatment applied to degrade the epoxy resin matrix of a CFRP are here analysed. Two conditions were chosen so as to reach two degradation efficiency levels of the steam thermolysis. Several carbon fibre samples were selected for mechanical testing carried out either on single filaments using single fibre tensile tests or on fibre tows using bundle tensile tests. It is shown that the single fibre tensile test leads to a wide variability of statistical parameters derived from the analysis. Bundle tensile tests results were able to indicate that fibre strength of recycled carbon fibre is similar to corresponding as-received carbon fibres thanks to a statistically relevant database. Wide number of tested filaments enabled indeed to obtain low scatters.
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Hager, Izabela, and Katarzyna Mróz. "Role of Polypropylene Fibres in Concrete Spalling Risk Mitigation in Fire and Test Methods of Fibres Effectiveness Evaluation." Materials 12, no. 23 (November 23, 2019): 3869. http://dx.doi.org/10.3390/ma12233869.
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The explosive behaviour of concrete in fire is observed in rapidly heated concrete. The main factors controlling the occurrence of spalling are related to the material’s low porosity and high density as well as the limited ability to transport gases and liquids. Thus, for high-strength, ultrahigh-strength, and reactive powder concrete, the risk of spalling is much higher than for normal-strength concrete. The paper presents the discussion on the leading hypothesis concerning the occurrence of concrete spalling. Moreover, the methods for spalling prevention, such as polypropylene fibre application, which has been found to be an effective technological solution for preventing the occurrence of spalling, are presented. Various tests and testing protocols are used to screen concrete mixes propensity toward spalling and to evaluate the polypropylene fibres’ effectiveness in spalling risk mitigation. The most effective testing methods were selected and their advantages were presented in the paper. The review was based mainly on the authors’ experiences regarding high performance concrete, reactive powder concrete testing, and observations on the effect of polypropylene fibres on material behaviour at high temperature.
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Wagner, H. D., and S. Ling. "An Energy-Based interpretation of Interfacial Adhesion from Single Fibre Composite Fragmentation Testing." Advanced Composites Letters 2, no. 5 (September 1993): 096369359300200. http://dx.doi.org/10.1177/096369359300200503.
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An energy balance approach is proposed for the single fibre composite (or fragmentation) test, by which the degree of fibre-matrix bonding is quantified by means of the interfacial energy, rather than the interfacial shear strength, as a function of the fibre geometrical and mechanical characteristics, the stress transfer length, and the debonding length. The validity of the approach is discussed using E-glass fibres embedded in epoxy, both in the dry state and in the presence of hot distilled water.
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Drdlová, Martina, Radek Řídký, and René Čechmánek. "Influence of Fibre Type and Fibre Volume Fraction on Dynamic Properties of Slurry Infiltrated Fibre Concrete." Materials Science Forum 865 (August 2016): 135–40. http://dx.doi.org/10.4028/www.scientific.net/msf.865.135.
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The effect of fibre type and fibre amount on physico-mechanical properties of slurry infiltrated fibre concrete (SIFCON) at both quasi-static and dynamic load was evaluated experimentally. SIFCON is a special type of cement-based composite with high fibre volume fraction, extremely strong and ductile. Test specimens were prepared with 7 types of steel fibres (with different shape and mechanical parameters) in four volume fractions (7.5-15 vol. %). High performance fibre-reinforced concrete (HPFRC) has also been cast and tested for comparison purposes. The impact test has been carried out by using an in-house manufactured impact testing machine based on drop test principle. The test results revealed that SIFCON slab with 15 vol. % fibre content exhibits superior energy-absorption characteristics when compared to other slab specimens. Diameter of the fibres plays an important role for both strength and energy absorption capacity of SIFCON - using of low-diameter fibres with higher aspect ratio leads to the best results.
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Wiemer, Niels, Alexander Wetzel, Maximilian Schleiting, Philipp Krooß, Malte Vollmer, Thomas Niendorf, Stefan Böhm, and Bernhard Middendorf. "Effect of Fibre Material and Fibre Roughness on the Pullout Behaviour of Metallic Micro Fibres Embedded in UHPC." Materials 13, no. 14 (July 14, 2020): 3128. http://dx.doi.org/10.3390/ma13143128.
Full textAbstract:
The use of micro fibres in Ultra-High-Performance Concrete (UHPC) as reinforcement increases tensile strength and especially improves the post-cracking behaviour. Without using fibres, the dense structure of the concrete matrix results in a brittle failure upon loading. To counteract this behaviour by fibre reinforcement, an optimal bond between fibre and cementitious matrix is essential. For the composite properties not only the initial surfaces of the materials are important, but also the bonding characteristics at the interfacial transition zone (ITZ), which changes upon the joining of both materials. These changes are mainly induced by the bond of cementitious phases on the fibre. In the present work, three fibre types were used: steel fibres with brass coating, stainless-steel fibres as well as nickel-titanium shape memory alloys (SMA). SMA fibres have the ability of “remembering” an imprinted shape (referred to as shape memory effect), triggered by thermal activation or stress, principally providing for superior performance of the fibre-reinforced UHPC. However, previous studies have shown that NiTi-fibres have a much lower bond strength to the concrete matrix than steel fibres, eventually leading to a deterioration of the mechanical properties of the composite. Accordingly, the bond between both materials has to be improved. A possible strategy is to roughen the fibre surfaces to varying degrees by laser treatment. As a result, it can be shown that laser treated fibres are characterised by improved bonding behaviour. In order to determine the bond strength of straight, smooth fibres of different metal alloy compositions, the present study characterized multiple fibres in series with a Compact-Tension-Shear (CTS) device. For critical evaluation, results obtained by these tests are compared with the results of conventional testing procedures, i.e., bending tests employing concrete prisms with fibre reinforcements. The bond behaviour is compared with the results of the flexural strength of prisms (4 × 4 × 16 cm3) with fibre reinforcements.
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Hüsken, Götz, Lars-Christian Wagner, Gregor J. G. Gluth, Stephan Pirskawetz, and Hans-Carsten Kühne. "APPLICATION OF STEEL FIBRES IN ALKALI-ACTIVATED MORTARS." Acta Polytechnica CTU Proceedings 27 (June 11, 2020): 90–95. http://dx.doi.org/10.14311/app.2020.27.0090.
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Alkali-activated materials are ideal for the repair of concrete structures in harsh environmental conditions due to their high durability in chemically aggressive environments. However, slag-based mortars, in particular, are prone to shrinkage and associated cracks. In this respect, the application of steel fibres is one solution to reduce the formation of shrinkage induced cracks and to improve post cracking behaviour of these mortars. This study investigated the influence of two different types of steel fibres on the tensile properties of two alkali-activated mortars. Direct tensile tests and single fibre pull-outs were performed to analyse the determining failure modes both on macro and micro scale. Mechanical testing was accompanied by non-destructive testing methods such as digital image correlation and acoustic emission for a detailed analysis of the fracture process.
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Bakri, B., A. E. E. Putra, A. A. Mochtar, I. Renreng, and H. Arsyad. "Sodium Bicarbonate Treatment on Mechanical and Morphological Properties of Coir Fibres." International Journal of Automotive and Mechanical Engineering 15, no. 3 (October 5, 2018): 5562–72. http://dx.doi.org/10.15282/ijame.15.3.2018.12.0427.
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Natural fibres as reinforcement of composite have been applied during the last decade. One of natural fibre has been used as reinforcement is coir fibre. As reinforcement of composite, such fibre needs treatment to improve compatibility with its matrix with suitable treatment. In this paper, surface treatment of such fibre was conducted using sodium bicarbonate (NaHCO3) solution with various densities and soaking time differences. Mechanical and morphological properties of coir fibre were investigated. Coir fibres were soaked in the 8 wt.%, 10 wt.%, and 12 wt.% sodium bicarbonate solution for 24 hours and 120 hours. After treatment, coir fibres were characterized with tensile testing, scanning electron microscope (SEM), Fourier transform infrared (FTIR) and x-ray diffraction (XRD). The results suggested that mechanical properties of coir fibre after sodium bicarbonate solution changed for all densities and soaking time. The coir fibre treated in 12 wt.% sodium bicarbonate for soaking time 120 hours has highest tensile strength. The surface morphology of fibre was analyzed by using SEM. It showed micropores on the fibre surface which may influence the mechanical properties of coir fibre.
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Osorio, L., E. Trujillo, F. Lens, J. Ivens, I. Verpoest, and AW Van Vuure. "In-depth study of the microstructure of bamboo fibres and their relation to the mechanical properties." Journal of Reinforced Plastics and Composites 37, no. 17 (June 17, 2018): 1099–113. http://dx.doi.org/10.1177/0731684418783055.
Full textAbstract:
The mechanical properties of bamboo technical fibre, from the species Guadua angustifolia, have been studied showing values of strength up to 800 MPa and E-modulus up to 43 GPa, proving their adequate tensile properties that make this natural fibre suitable as reinforcement in composite materials. To fully explore the good mechanical properties and to make an adequate use of this new reinforcement, it is indispensable to comprehensively understand the fibre behaviour as a function of the microstructure. Microscopic observations have provided us with an extensive knowledge of the complex microstructure of this natural fibre from the macroscale down to the microscale level where different features like the distribution of the elementary fibres within the fibre bundle, dimensions and layering pattern of the elementary fibres and the main microfibrillar angles could be measured. The Young’s modulus of the elementary fibre is analysed based on the micromechanics of composite materials, commonly used for unidirectional short fibre composites, and the fibre microstructure. The predicted results are in reasonable agreement with experimental data, showing the appropriateness of the model for describing the elementary fibre stiffness. Also, the failure modes of single fibres after tensile testing are analysed by microscopic observations, to have an indication of the stress development in the elementary fibres and the different failure mechanisms.
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Richely, Emmanuelle, Sylvie Durand, Alessia Melelli, Alexander Kao, Anthony Magueresse, Hom Dhakal, Tatyana Gorshkova, et al. "Novel Insight into the Intricate Shape of Flax Fibre Lumen." Fibers 9, no. 4 (April 6, 2021): 24. http://dx.doi.org/10.3390/fib9040024.
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Plant fibres and especially flax can be distinguished from most synthetic fibres by their intricate shape and intrinsic porosity called lumen, which is usually assumed to be tubular. However, the real shape appears more complex and thus might induce stress concentrations influencing the fibre performance. This study proposes a novel representation of flax fibre lumen and its variations along the fibre, an interpretation of its origin and effect on flax fibre tensile properties. This investigation was conducted at the crossroads of complementary characterization techniques: optical and scanning electron microscopy (SEM), high-resolution X-ray microtomography (µCT) and mechanical tests at the cell-wall and fibre scale by atomic force microscopy (AFM) in Peak-Force Quantitative Nano-Mechanical property mapping (PF-QNM) mode and micromechanical tensile testing. Converging results highlight the difficulty of drawing a single geometric reference for the lumen. AFM and optical microscopy depict central cavities of different sizes and shapes. Porosity contents, varying from 0.4 to 7.2%, are estimated by high-resolution µCT. Furthermore, variations of lumen size are reported along the fibres. This intricate lumen shape might originate from the cell wall thickening and cell death but particular attention should also be paid to the effects of post mortem processes such as drying, retting and mechanical extraction of the fibre as well as sample preparation. Finally, SEM observation following tensile testing demonstrates the combined effect of geometrical inhomogeneities such as defects and intricate lumen porosity to drive the failure of the fibre.
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Bachtiar, Dandi, Januar Parlaungan Siregar, Ahmad Syahrizan bin Sulaiman, and Mohd Ruzaimi bin Mat Rejab. "Tensile Properties of Hybrid Sugar Palm/Kenaf Fibre Reinforced Polypropylene Composites." Applied Mechanics and Materials 695 (November 2014): 155–58. http://dx.doi.org/10.4028/www.scientific.net/amm.695.155.
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Study on hybridization of two types of natural fibres reinforced thermoplastic composites was an alternative option in research on natural composites. This paper presents the investigation on tensile properties of combining sugar palm and kenaf fibres reinforced polypropylene composites. The hybrid composites were prepared with different amounts of fibres (i.e. 10%, 20% and 30% by weight percent) while the ratios between sugar palm and kenaf fibre are 30:70, 50:50 and 70:30. The composites have been fabricated using melt mixer technique and followed by compression molding process. The specimens were cut according ASTM Standard D638 for conducting the tensile testing. The results shown that tensile strength of composites tend to decreased when the content of loading fibres increased. Among the composites with different ratios, the hybrid composites that contain more kenaf fibres exhibit the higher value in tensile strength than the composites that contain more sugar palm fibres.
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Aaditaa, Aaditaa, and Shahnaz Jahan. "Extraction and processing of Bast fibres from Ficus glomerata- A new source for non- conventional fibres." Journal of Applied and Natural Science 10, no. 2 (June 1, 2018): 661–66. http://dx.doi.org/10.31018/jans.v10i2.1759.
Full textAbstract:
The increasing global preference towards the natural products rather than synthetic products has increased the attraction of tourists to the local markets. Ficus glomerata fibres is one of the suitable source as raw material for making natural products like carrier bags, baskets, belts and some handicraft items. Fibres from F. glomerata stems were extracted by using water retting method. After retting, the fibres were scoured using sodium hydroxide (NaOH) for making them suitable to form the different produucts from the processed fibres such as yarn, nonwoven, woven and knitted fabrics. Scouring conditions such as chemical concentration and processing time were evaluated on the basis of physical properties of fibres such as tenacity, elongation and fineness. The optimization results obtained from testing of physical properties of fibres shows that, the 3% concentration of sodium hydroxide (NaOH) and 60 minutes processing time was found promising for the treatment of fibres. The improvement in F. glomerata fibres through proper processing can yield value added fibres and thus can enhance the potential utility of these fibres in diversified sectors. So, the F. glomaerata fibres has a potential to provide an important role in making space for natural fibre products in the outside market.
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Jiang, Zhaohui, Zengge Guo, Congcong Pu, Jing Wang, Zhao Jia, Changfa Xiao, and Shulin An. "Preparation and properties of melt-spinning fluorinated ethylene propylene fibres." High Performance Polymers 29, no. 4 (May 27, 2016): 476–83. http://dx.doi.org/10.1177/0954008316651689.
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In this work, a novel fibre, fluorinated ethylene propylene (FEP) filament, was fabricated by melt-spinning. In addition, the properties of FEP fibres were investigated through apparent morphological observation, tensile testing, dry-hot shrinkage, differential scanning calorimetry, thermogramitric analysis (TGA) and Fourier transform infrared spectroscopy. Apparent morphological observation shows that FEP fibres present circular cross-sections and smooth surfaces. Just like the conventional fibres prepared by melt-spinning, such as poly (ethylene terephthalate) (PET) and polyamide 6, the stress–strain curves of FEP fibres show obvious stress yield points. The elastic recovery ratio of FEP fibres (80%) is much greater than that of polytetrafluoroethylene (PTFE) fibres (40%), endowing FEP textiles good wrinkle resistance. When FEP fibres are deposited in flame, smoke and droplets do not appear but shrinkage does occur. After treatment in hot air, the breaking strength of FEP fibres decreases, but the elongation at break increases. The melting temperature of FEP fibres is as closely high as that of the PET fibres, while the crystallization temperature is much higher, which puts forward greater challenges for FEP spinning. Compared with PTFE fibres, the crystallinity and the melting temperature of FEP fibres are much lower. TGA results demonstrate that FEP fibres present excellent thermal stability that is as stable as that of the PTFE fibres.
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Pečlin, Polona, and Janez Rozman. "Alternative Paradigm of Selective Vagus Nerve Stimulation Tested on an Isolated Porcine Vagus Nerve." Scientific World Journal 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/310283.
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Alternative paradigm for spatial and fibre-type selective vagus nerve stimulation (VNS) was developed using realistic structural topography and tested in an isolated segment of a porcine cervical left vagus nerve (LVN). A spiral cuff (cuff) containing a matrix of ninety-nine electrodes was developed for selective VNS. A quasitrapezoidal stimulating pulse (stimulus) was applied to the LVN via an appointed group of three electrodes (triplet). The triplet and stimulus were configured to predominantly stimulate the B-fibres, minimizing stimulation of the A-fibres and by-passing the stimulation of the C-fibres. To assess which fibres made the most probable contribution to the neural response (NR) during selective VNS, the distribution of conduction velocity (CV) within the LVN was considered. Experimental testing of the paradigm showed the existence of certain parameters and waveforms of the stimulus, for which the contribution of the A-fibres to the NR was slightly reduced and that of the B-fibres was slightly enlarged. The cuff provided satisfactory fascicle discrimination in selective VNS as well as satisfactory fascicle discrimination during NR recording. However, in the present stage of development, fibre-type VNS remained rather limited.
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Saefkow, Martin, Matthias List, Andreas Schubert, Andreas Lohmüller, and Robert F. Singer. "Continuous Powder Extrusion for Fabrication of Carbon Fibre Reinforced Aluminium." Key Engineering Materials 742 (July 2017): 158–64. http://dx.doi.org/10.4028/www.scientific.net/kem.742.158.
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Short fibre reinforced aluminium was produced using the Temconex® process which is a continuous extrusion using a mixture of metal powder and ceramic short fibre as feedstock. The Temconex® process was derived and further developed from the ConformTM process which uses metal rod rather than powder as feedstock. In the present paper the effect of the prechamber length on the mechanical properties was examined. As material Al99.7 powder with different volume fractions of milled carbon fibres was used. Distribution, orientation and geometry of the embedded fibres were examined using light microscopy. The mechanical properties were determined via tensile testing and resonance frequency analysis. An important increase of the Young’s modulus is observed because of the introduction of fibres. It can be rationalized based on Clyne’s Shear Lag model. Results show that an extension of the prechamber enhances the Young’s modulus and the elongation of fracture due to reduced fibre fracture and better fibre alignment.
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Poh-Yap, S., U. Johnson-Alengaram, K. Hung-Mo, and M. Zamin-Jumaat. "High strength oil palm shell concrete beams reinforced with steel fibres." Materiales de Construcción 67, no. 328 (October 23, 2017): 142. http://dx.doi.org/10.3989/mc.2017.11616.
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The utilization of lightweight oil palm shell to produce high strength lightweight sustainable material has led many researchers towards its commercialization as structural concrete. However, the low tensile strength of Oil Palm Shell Concrete (OPSC) has hindered its development. This study aims to enhance the mechanical properties and flexural behaviours of OPSC by the addition of steel fibres of up to 3% by volume, to produce oil palm shell fibre-reinforced concrete (OPSFRC). The experimental results showed that the steel fibres significantly enhanced the mechanical properties of OPSFRC. The highest compressive strength, splitting tensile and flexural strengths of 55, 11.0 and 18.5 MPa, respectively, were achieved in the OPSFRC mix reinforced with 3% steel fibres. In addition, the flexural beam testing on OPSFRC beams with 3% steel fibres showed that the steel fibre reinforcement up to 3% produced notable increments in the moment capacity and crack resistance of OPSFRC beams, but accompanied by reduction in the ductility.
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Terziev, Nasko, Geoffrey Daniel, and Ann Marklund. "Dislocations in Norway spruce fibres and their effect on properties of pulp and paper." Holzforschung 59, no. 2 (February 1, 2005): 163–69. http://dx.doi.org/10.1515/hf.2005.025.
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Abstract Wood “cell-wall deformation” is a comprehensive term describing any physical dislocation in the wall caused by mechanical forces. The development and effect of fibre dislocations on wood fibres, and their ultimate impact on the mechanical properties of paper remain rather obscure and controversial. Dislocations are difficult to quantify through a lack of defined measurable features, and research is aggravated by the inherent difficulties of applying statistical tools. A direct approach for studying the effect of dislocations on the mechanical properties of paper was used in this study. Dislocations in fibre cell walls were introduced by exposing whole wood fibres in mature and juvenile wood samples to compression stress. Sapwood samples of Norway spruce (Picea abies Karst.) were loaded by compression to their ultimate strength using an Alwetron-50 universal testing machine. Failure of samples conditioned to a moisture content of 9–15% always occurred in an oblique (relative to the fibre axis) plane and all fibres in the plane were deformed. When samples were loaded in a wet condition (i.e., moisture content close to the fibre saturation point), failure occurred at one end of the samples, resulting in highly disorganised fibres. Pulp and paper from the compressed fibres were produced and the mechanical properties of the paper were tested. Results of the mechanical tests were compared statistically to results derived from paper made from matched non-compressed control samples. Morphological features of fibres and dislocations after compression failure were characterised using microscopy (scanning electron microscopy, polarised light) on the whole wood and macerated fibres before and after paper testing. The above experimental approach showed that paper made from control samples had significantly better mechanical properties than paper made from samples loaded by compression under dry or wet conditions. At a tensile index of 90 N m/g, the tear index was measured as 23.6 mN m2/g for controls, while the corresponding values for compressed wet wood samples was 12.6 and 16.3 mN m2/g for samples at 9–15% moisture content. Paper made from juvenile wood also showed lower mechanical properties compared to controls. The results prove the negative effect of dislocations on the mechanical properties of paper in the worst case scenario and are of practical importance.
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Fleet, M. R., L. Li, and Y. Ru. "Assessment of contamination of wool by dark and medullated fibres using near infrared spectroscopy." Australian Journal of Experimental Agriculture 46, no. 5 (2006): 605. http://dx.doi.org/10.1071/ea04027.
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Increased crossbreeding of Merino sheep in Australia, involving coloured or highly medullated sire breeds, has increased the risk of dark and highly medullated fibres in wool lots. Commercial implementation of the Dark and Medullated Fibre Risk Scheme, based on producer information, is identifying to buyers some of these risks and technology is sought to provide an inexpensive method for routine presale testing of greasy wool lots. One measurement concept assessed the ability of near infrared spectroscopy (NIRS) to predict variation in levels of pigmented fibres or highly medullated fibres in wool. The project used either ‘seeded’ wool samples or naturally contaminated samples with measured reference values as well as different methods of sample preparation of wool fibre (in air or immersed in benzyl alcohol) or the solutions from alkali hydrolysis of wool fibre and NIRS measurement (reflectance v. transmission). NIRS can predict variation in trace levels of pigmented fibre or highly medullated white fibres (kemp) in wool and, among the methods assessed, reflectance analysis of wool fibre in air was generally better than the other options considered. Calibration models for NIRS reflectance measurement of 5 g wool samples ‘seeded’ with 1–50 black-pigmented, tan-pigmented or white kemp fibres gave coefficients of determination (R2) of 0.96, 0.88 and 0.82 with standard errors of cross-validation (SECV) of 4.34, 6.97 and 7.17 fibres per 5 g sample, respectively. However, these calibration equations generally did not predict variations in the reference values for 3 other sets of naturally contaminated samples. New calibration equations determined for each of the sets of naturally contaminated samples also predicted variation in the pigmented fibre reference values, with the extent of agreement depending on the accuracy of the reference data as well as sample preparation and method of measurement. Calibration models for NIRS reflectance measurement of wool fibre from the 3 sets of naturally contaminated samples produced R2 = 0.99, 0.71 and 0.92 with SECV = 0.923, 6.43 and 4.54 pigmented fibres per 5 g sample, respectively. However, these calibrations and those obtained from various combinations of the wool sets also had limited ability to predict variation in pigmented fibre reference values in other independent or excluded samples. Refinement of the technique and development of calibrations with extensive and reliable reference data, representing all of the wool variation likely to be encountered, may allow this NIRS potential to become relevant in the presale testing of wool as an inexpensive measurement procedure for estimating dark and medullated fibre content.
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Aldosari, Salem Mohammed, Muhammad A. Khan, and Sameer Rahatekar. "Manufacturing Pitch and Polyethylene Blends-Based Fibres as Potential Carbon Fibre Precursors." Polymers 13, no. 9 (April 29, 2021): 1445. http://dx.doi.org/10.3390/polym13091445.
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The advantage of mesophase pitch-based carbon fibres is their high modulus, but pitch-based carbon fibres and precursors are very brittle. This paper reports the development of a unique manufacturing method using a blend of pitch and linear low-density polyethylene (LLDPE) from which it is possible to obtain precursors that are less brittle than neat pitch fibres. This study reports on the structure and properties of pitch and LLDPE blend precursors with LLDPE content ranging from 5 wt% to 20 wt%. Fibre microstructure was determined using scanning electron microscopy (SEM), which showed a two-phase region having distinct pitch fibre and LLDPE regions. Tensile testing of neat pitch fibres showed low strain to failure (brittle), but as the percentage of LLDPE was increased, the strain to failure and tensile strength both increased by a factor of more than 7. DSC characterisation of the melting/crystallization behaviour of LLDPE showed melting occurred around 120 °C to 124 °C, with crystallization between 99 °C and 103 °C. TGA measurements showed that for 5 wt%, 10 wt% LLDPE thermal stability was excellent to 800 °C. Blend pitch/LLDPE carbon fibres showed reduced brittleness combined with excellent thermal stability, and thus are a candidate as a potential precursor for pitch-based carbon fibre manufacturing.
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Nunna, Srinivas, Maxime Maghe, Rohit Rana, Russell Varley, Daniel Knorr, James Sands, Claudia Creighton, Luke Henderson, and Minoo Naebe. "Time Dependent Structure and Property Evolution in Fibres during Continuous Carbon Fibre Manufacturing." Materials 12, no. 7 (April 1, 2019): 1069. http://dx.doi.org/10.3390/ma12071069.
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Here we report on how residence time influences the evolution of the structure and properties through each stage of the carbon fibre manufacturing process. The chemical structural transformations and density variations in stabilized fibres were monitored by Fourier Transform Infrared Spectroscopy and density column studies. The microstructural evolution and property variation in subsequent carbon fibres were studied by X-ray diffraction and monofilament tensile testing methods, which indicated that the fibres thermally stabilized at longer residence times showed higher degrees of structural conversion and attained higher densities. Overall, the density of stabilized fibres was maintained in the optimal range of 1.33 to 1.37 g/cm3. Interestingly, carbon fibres manufactured from higher density stabilized fibres possessed lower apparent crystallite size (1.599 nm). Moreover, the tensile strength of carbon fibres obtained from stabilized fibres at the high end of the observed range (density: 1.37 g/cm3) was at least 20% higher than the carbon fibres manufactured from low density (1.33 g/cm3) stabilized fibres. Conversely, the tensile modulus of carbon fibres produced from low density stabilized fibres was at least 17 GPa higher than those from high density stabilized fibres. Finally, it was shown that there is potential to customize the required properties of resultant carbon fibres suiting specific applications via careful control of residence time during the stabilization stage.