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1
Mukhtar, Faisal M., and Olaniyi Arowojolu. "Recent developments in experimental and computational studies of hygrothermal effects on the bond between FRP and concrete." Journal of Reinforced Plastics and Composites 39, no. 11-12 (March 22, 2020): 422–42. http://dx.doi.org/10.1177/0731684420912332.
Повний текст джерелаАнотація:
The performance of fiber reinforced polymer externally bonded to concrete is greatly influenced by the environmental conditions to which it is exposed during service. Temperature and humidity are the two common environmental factors that alter the bond behavior of externally bonded fiber reinforced polymer. This paper reviews the experimental and computational approaches used to evaluate the hygrothermal effects—that is, the effect of temperature and humidity—on the durability of the fiber reinforced polymer–concrete bond, as well as on the bond’s performance under loading conditions. Some experimental testing conducted in the laboratory and in situ are critically reviewed and presented. Implemented approaches for improving bond performance under hygrothermal conditions and their modeling techniques are also presented. The paper concludes by discussing the review’s salient issues. The ongoing wide application of externally bonded fiber reinforced polymer creates opportunities for new research on improving and predicting the bond strength of fiber reinforced polymer concrete under hygrothermal conditions.
2
Ismail, Nur Farhani, Nabilah Afiqah Mohd Radzuan, Abu Bakar Sulong, Norhamidi Muhamad, and Che Hassan Che Haron. "The Effect of Alkali Treatment on Physical, Mechanical and Thermal Properties of Kenaf Fiber and Polymer Epoxy Composites." Polymers 13, no. 12 (June 19, 2021): 2005. http://dx.doi.org/10.3390/polym13122005.
Повний текст джерелаАнотація:
The use of kenaf fiber as a reinforcement material for polymer composites is gaining popularity, especially in the production of automotive components. The main objective of this current work is to relate the effect of alkali treatment on the single fiber itself and the composite material simultaneously. The effect of temperature condition during mechanical testing is also investigated. Composite materials with discontinuous natural kenaf fibers and epoxy resin were fabricated using a compression moulding process. The epoxy composites were reinforced with 50 wt% untreated and treated kenaf fibers. The kenaf fiber was treated with NaOH solution (6% by weight) for 24 h at room temperature. Kenaf fiber treated with NaOH treatment had a clean surface and no impurities. For the first time we can see that alkali treatment had a damaging effect on the mechanical properties of kenaf fibers itself and the treated kenaf/epoxy composites. The composite reinforced with untreated kenaf fiber and treated kenaf fiber showed increased tensile strength (72.85% and 12.97%, respectively) compared to the neat epoxy. Reinforcement of the composite with treated kenaf fiber decreased the tensile strength due to the fiber pull out and the formation of voids which weakens the adhesion between the fibers and matrix. The temperature conditions also play an important role in composites with a significant impact on the deterioration of composite materials. Treated kenaf fiber has thermal stability and is not sensitive to temperature and as a result reinforcement with treated kenaf gives a lower loss value of 76%.
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Anis, Arfat, Shan Faiz, and Saeed M. Al-Zahrani. "Effects of extrusion parameters on tensile strength of polybenzimidazole fiber-reinforced high density polyethylene composites." Journal of Polymer Engineering 36, no. 2 (March 1, 2016): 113–18. http://dx.doi.org/10.1515/polyeng-2015-0006.
Повний текст джерелаАнотація:
Abstract The objectives of this study were to examine the effects of fiber content and extrusion parameters on polybenzimidazole (PBI) fiber-reinforced polyethylene composites and to determine the optimum values for the tensile strength. The PBI fiber was physically mixed with high density polyethylene (HDPE) and then extruded through a twin screw extruder. The extrusion parameters were studied at different levels, barrel temperatures at 240°C, 250°C and 260°C and screw speeds at 12 rpm, 15 rpm and 18 rpm. The tensile strength was measured using a universal testing machine. A response surface experimental design using Design-Expert was applied to investigate the effect of fiber loading and extrusion parameters (barrel temperature, screw speed) on tensile properties of the resulting composite and consequently analyzing the optimized value for these parameters to yield maximum tensile strength. The analysis predicted a linear model which suggests that in order to achieve maximum tensile strength the screw speed should be 18 rpm, the barrel temperature at 240°C and at a fiber loading of 2%.
4
Xiao, Kai Tao, Jia Zheng Li, and Hua Quan Yang. "Study of Crack Resistance Property of Polyvinyl Alcohol Fiber Reinforced Concrete." Advanced Materials Research 287-290 (July 2011): 178–82. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.178.
Повний текст джерелаАнотація:
The strength, ultimate tensile value, compressive elastic modulus and drying shrinkage of polyvinyl alcohol fiber reinforced concrete were studied by tests, and its crack resistance property was also studied by plate method and temperature stress testing machine. The test results showed that PVA fiber could improve the tensile strength and ultimate tensile value of concrete, lower its compressive elastic modulus and drying shrinkage, restrain its early plastic shrinkage and drying shrinkage cracks, reduce its cracking temperature and improve the crack resistance property of concrete, moreover, the effect of long PVA fiber was better.
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Valle, Vladimir, Alex Aguilar, Jeronimo Kreiker, Belén Raggiotti, and Francisco Cadena. "Oil Palm Empty Fruit Bunch (OPEFB) Fiber-Reinforced Acrylic Thermoplastic Composites: Effect of Salt Fog Aging on Tensile, Spectrophotometric, and Thermogravimetric Properties." International Journal of Polymer Science 2022 (April 15, 2022): 1–18. http://dx.doi.org/10.1155/2022/6372264.
Повний текст джерелаАнотація:
The prioritization of agroindustry fiber wastes as raw materials in development of composites has become a challenge to obtain higher value-added products with targeted applications. In this study, natural fiber-reinforced polymer matrix composites were elaborated using two fiber sizes (605 μm and 633 μm) of oil palm empty fruit bunch (OPEFB) and acrylic thermoplastic resin. In doing so, resin and fibers were mixed at room temperature by maintaining filler content of 42 wt. % for all formulations. In addition, thermomechanical compression moulding was used as composite manufacturing process at four processing temperatures (80, 100, 120, and 140°C). All formulations were subsequently exposed to salt fog spray aging for 330 hours. The effects of accelerated aging process on mechanical, spectrophotometric, and thermogravimetric characteristics were studied. On the whole, results have shown feasibility to use a facile method to elaborate composites based on waterborne acrylic matrix and OPEFB fibers. After salt spray testing, it was observed detectable levels of Aspergillus spp. of fungi in all samples, as a result of phylogenetic organization of microbial activity. Tensile behavior of composites was significantly influenced by processing temperature and fiber size. In broad terms, their overall mechanical properties were improved by the increase of temperature. Additionally, infrared spectroscopy results showed important bands mainly associated to biodegradation of cellulose, hemicellulose, and lignin. On the other hand, two degradation stages were mainly identified in thermogravimetric evaluation. Noteworthy, aging had no significant effect on the thermal properties of composites.
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Adeniran, Olusanmi, Norman Osa-uwagboe, Weilong Cong, and Monsuru Ramoni. "Fabrication Temperature-Related Porosity Effects on the Mechanical Properties of Additively Manufactured CFRP Composites." Journal of Composites Science 7, no. 1 (January 5, 2023): 12. http://dx.doi.org/10.3390/jcs7010012.
Повний текст джерелаАнотація:
The use of additive manufacturing in fabricating composite components has been gaining traction in the past decade. However, some issues with mechanical performance still need to be resolved. The issue of material porosity remains a pertinent one which needs more understanding to be able to come up with more viable solutions. Different researchers have examined the subject; however, more research to quantitatively determine fabrication temperatures effects at the micro-scale are still needed. This study employed micro-CT scan analysis to quantitatively compare fabrication temperatures effect at 230 °C, 250 °C, 270 °C, and 290 °C on the mechanical properties of AM fabricated carbon-fiber-reinforces plastic (CFRP) composites, testing carbon fiber-reinforced polyamide (CF-PA) and carbon fiber-reinforced acrylonitrile butadiene styrene (CF-ABS) samples. This micro-CT examination followed an SEM evaluation, which was used to determine temperature effects on interlayer and intralayer porosity generation. The porosity volume was related to the mechanical properties, in which it was determined how temperatures influence porosity volumes. It was also determined that fabrication temperature generally affects semicrystalline composites more than amorphous composites. The overall porosity volumes from the interlayer and intralayer voids were determined, with the interlayer voids being more influential in influencing the mechanical properties.
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Miyano, Yasushi, Masayuki Nakada, and Yo Yoshikoshi. "Statistical creep failure time of unidirectional carbon fiber reinforced plastic under bending load." Journal of Composite Materials 56, no. 8 (February 8, 2022): 1153–64. http://dx.doi.org/10.1177/00219983211072959.
Повний текст джерелаАнотація:
Our developed accelerated testing methodology (ATM) based on the matrix resin viscoelasticity for the creep and fatigue failure life prediction of fiber reinforced polymers (FRP) was applied to the statistical prediction of long-term creep failure life for the longitudinal bending of unidirectional Carbon fiber reinforced plastic (CFRP) laminates which is an important basic item for the durability design of CFRP structures used for aircraft and others. As results, the statistical creep failure times measured under several constant bending loads at an arbitrary temperature for unidirectional CFRP laminates were agreed with the predicted results obtained by substituting the matrix resin viscoelasticity and the flexural static strengths of CFRP laminates statistically and easily measured at various temperatures into the formulation of ATM. The long-term creep strength under bending load at an arbitrary temperature predicted were compared with that under tension load obtained by our previous paper. It was clear that the creep strength under bending load degreases drastically with increase in time and temperature comparing with that under tension load; therefore, the effect of time and temperature on the creep failure life under bending load is larger than that under tension load.
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Patel, Himanshu V., and Harshit K. Dave. "The effect of stacking sequence and fiber orientation on tensile and flexural strength of fiber reinforced composite fabricated by VARTM process." Engineering Solid Mechanics 11, no. 1 (2023): 47–62. http://dx.doi.org/10.5267/j.esm.2022.9.001.
Повний текст джерелаАнотація:
In this study, Carbon, Glass, and Aramid fiber reinforced composite and their hybridized forms were fabricated using five different stacking sequences of the fabrics. Using the Vacuum Assisted Resin Transfer Molding (VARTM) procedure, epoxy resin was injected into these fabrics and allowed to cure at room temperature. From these five stacking sequences, a standard specimen with four different orientations viz. 0/90°, 15/75°, 30/60°, 45/-45° orientations were obtained using the Abrasive Water Jet Machining(AWJM) Process. The influence of stacking order and fiber orientation on tensile and flexural properties of composite was investigated. From the result of tensile testing, the highest and lowest tensile strength values were observed for neat carbon fiber reinforced composite at 0/90° orientation and at 45/-45° orientation respectively. The highest flexural strength was achieved in a hybrid combination of two layers of carbon, glass and aramid fabric for 0/90° whereas the lowest flexural strength was found in glass reinforced composite for the 45/-45° orientation.
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Song, You, Jiangang Deng, Zhuolin Xu, Yu Nie, and Zhenbo Lan. "Effect of Thermal Aging on Mechanical Properties and Color Difference of Glass Fiber/Polyetherimide (GF/PEI) Composites." Polymers 14, no. 1 (December 24, 2021): 67. http://dx.doi.org/10.3390/polym14010067.
Повний текст джерелаАнотація:
This research study is aimed at evaluating the mechanical characteristics in terms of tensile strength and flexural strength of glass fiber reinforced Polyetherimide (GF/PEI) under different thermal aging. Tensile testing and bending testing were performed on the thermally aged polyetherimide composites. The mechanical properties of the thermally aged samples were also correlated with their color difference. The experimental results showed that both the tensile strength and flexural strength of the GF/PEI composite samples decreased with increasing aging temperature. However, the elastic modulus of the composite samples is nearly independent on the thermal aging. The thermally aged samples exhibited brittle fracture, resulting in low strength and low ductility. The loss in strength after thermal aging could be also linked to the change of their color difference, which can indirectly reflect the change of the strength for the composites after thermal aging.
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Tefera, Getahun, Sarp Adali, and Glen Bright. "Mechanical Behavior of GFRP Laminates Exposed to Thermal and Moist Environmental Conditions: Experimental and Model Assessment." Polymers 14, no. 8 (April 9, 2022): 1523. http://dx.doi.org/10.3390/polym14081523.
Повний текст джерелаАнотація:
This paper presents an experimental and analytical study about the mechanical response at a different temperature on glass fiber-reinforced polymer laminates. The effect of different environmental conditions on compressive, tensile, stiffness, and viscoelastic behavior (storage modulus, loss modulus and damping ratio) of laminates were investigated. Before testing, laminates were preserved in a deep freezer at −80 °C, −20 °C, 0 °C, and room temperature (25 °C) for up to 60 days. Results confirmed that temperatures ranging from −80 to 50 °C, which were below the glass transition temperature of the epoxy resin, did not significantly affect the compressive, tensile, and stiffness performance of all laminates. When the testing temperature increased to 100 °C, the properties were decreased significantly due to the damaging of the fiber/matrix interface. Additionally, results obtained from dynamic mechanical analyses tests showed a drop-in storage modulus, high peaks in loss modulus and high damping factor at the glass transition region of the epoxy resin. The highest storage modulus, two phases of glassy states and highest damping ratio on the −80/G group of laminates were obtained. The accuracy of experimental results was assessed with empirical models on the storage modulus behavior of laminates. The empirical model developed by Gibson et al. provided accurate estimates of the storage modulus as a function of temperature and frequency. The remaining empirical models were less accurate and non-conservative estimations of laminates stiffness.
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Budiyantoro, Cahyo, Heru S. B. Rochardjo, and Gesang Nugroho. "Design, Manufacture, and Performance Testing of Extrusion–Pultrusion Machine for Fiber-Reinforced Thermoplastic Pellet Production." Machines 9, no. 2 (February 17, 2021): 42. http://dx.doi.org/10.3390/machines9020042.
Повний текст джерелаАнотація:
This study aimed to develop an extrusion and pultrusion system for producing carbon fiber-filled thermoplastic pellets. The extruder delivers a plastic melt to an impregnation die in sufficient volume and is pulled out along with the fibers. The fibers pass in a sideways stretched condition through spreader pins attached in the melt pool, which can then be wetted optimally. The wetting effect was also improved by immersing fiber in a coupling agent solution at an elevated temperature before feeding to the extruder die. For machine performance testing, polypropylene was used as a matrix resin with the following parameters: a screw speed of 5 rpm, a die temperature of 210 °C, and a pulling speed of 56 mm/s. The pull-out test was conducted to assess the interfacial shear strength (IFSS) between fibers and matrix. Scanning electron microscopy (SEM) was applied to characterize the quality of fiber impregnation. SEM characterized a good bonding performance between carbon fiber and the matrix. The average IFSS of the results indicated a good resistance of fiber–matrix bonding against a pulling force. It proved that the combination of the extrusion–pultrusion system can produce high-quality filaments as a raw material of composite pellets.
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Labasan, Kristin B., Aldrine Jay G. Espinosa, and Rebecca C. Nueva Espana. "Fabrication and characterization of bamboo fiber- reinforced polyethylene-polystyrene composites using glycerol as plasticizer." World Journal of Environmental Research 5, no. 1 (November 17, 2015): 137. http://dx.doi.org/10.18844/wjer.v5i1.97.
Повний текст джерелаАнотація:
<p>Fiber-reinforced polymer composites are composed of a polymer matrix (PE-PS) combined with a fiber (bamboo fibers) to provide conspicuous reinforcement. In light of recycling plastic and natural fibers, the research aim to fabricate and characterize bamboo fiber-reinforced polyethylene-polystyrene composites using glycerol as plasticizer. Specifically, the study investigated the effect on the physical and mechanical properties and water absorption of the composites by varying the following parameters: substitution of glycerol instead of the usual cooking oil in fabrication of DRM, and bamboo fiber loading. Using 1:3 PE-PS ratio, glycerol incorporation was done in DRM by melting together plastic and styrofoam wastes using a densifying machine at 150˚C. DRM samples with 70% (w/w) glycerol incorporation were then compared to the original DRM samples with 70% (w/w) cooking oil. The modified DRM were then loaded with 1, 2 and 3% bamboo fiber-reinforcement using a two-roll mill at 200˚C and compression molding machine at 200˚C and 50 kg/cm2 for 5 mins in the aluminium mold. The composites were characterized by Universal Testing Machine (tensile strength) following the ASTM standard D638. In addition, water absorption of the fabricated composites was tested using the standard method specified by ASTM D570.The bamboo fiber-reinforced polyethylene-polystyrene composites at 1:3 PE: PS ratio rendered better tensile strength and less water absorbed using 70% (w/w) glycerol as plasticizer and at 1% bamboo fiber loading. For future studies, it is recommended to study the impact of different parameters (glycerol percentage, time, temperature, pressure, fiber type and dimensions, fiber extraction, etc.) in the fabrication of the fiber-reinforced recycled plastic composites. Other characterizations of the fabricated plastic composite including thermal properties, leaching and biodegradation experiments and compressive and flexural strengths can also be done.</p><p>Keywords: Fiber-reinforced polymer, plasticizer, composites.</p>
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Zhu, Jihua, Yangjian Deng, Piyu Chen, Gang Wang, Hongguang Min, and Wujun Fang. "Prediction of Long-Term Tensile Properties of Glass Fiber Reinforced Composites under Acid-Base and Salt Environments." Polymers 14, no. 15 (July 26, 2022): 3031. http://dx.doi.org/10.3390/polym14153031.
Повний текст джерелаАнотація:
This study investigates the effects of deionized water, seawater, and solutions with various concentrations (5% and 10% by mass) of HCl and NaOH on the physical and mechanical properties of glass fiber reinforced polymers (GFRPs) through aging tests at 20 °C, 50 °C, and 80 °C. The tensile properties of GFRP were assessed by tensile testing at room temperature, and the strain during the tensile process was observed using digital image correlation. Additionally, the degradation mechanism was analyzed using scanning electron microscopy, and long-term tensile properties were predicted based on the Arrhenius model. The results indicated that the tensile strength of the GFRP decreased by 22%, 71%, and 87% after 56 d of exposure to 5% NaOH solutions at 20 °C, 50 °C, and 80 °C, respectively. The alkaline solutions had a more severe effect on the GFRP than deionized water, seawater, and acidic solutions. The experimental values and Arrhenius model predictions were found to be in good agreement with each other.
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Sabarinathan, P., VE Annamalai, K. Rajkumar, and K. Vishal. "Effects of recovered brown alumina filler loading on mechanical, hygrothermal and thermal properties of glass fiber–reinforced epoxy polymer composite." Polymers and Polymer Composites 29, no. 9_suppl (September 23, 2021): S1092—S1102. http://dx.doi.org/10.1177/09673911211046780.
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This study investigates the efficiency of recovered brown alumina (RBA) particles filled in epoxy glass-fiber composites. The RBA particles were obtained from grinding wheel rejects with the help of the mechanical crushing process. Recovered particles finer than 120 grit were used as particulate filler for composite preparation. Composites were processed through a hand-layup technique by varying RBA filler loading percentages (0, 5, 10, 15, and 20 wt.%) in a glass fiber–reinforced epoxy matrix. Physical, mechanical, water absorption, and thermal properties of the composites were tested experimentally. By suitable addition of RBA, it is possible to tailor the shore-D hardness, tensile modulus, flexural strength, flexural modulus, and maximum degradation temperature. The 20%-filled RBA composite shows the maximum flexural strength of 382 MPa, and the shore-D hardness value was 85. The fracture surface shows a failure mechanism dominated by matrix cracking and debonding of fiber/particles from the interface. Hygrothermal testing of the RBA20-filled composite reveals 9% and 4% reduction in tensile and flexural properties. The thermal stability of the glass fiber–reinforced composite improves as the filler percentage increases. Maximum thermal stability of 435°C was observed in 20%-filled RBA polymer composite.
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Raja, Thandavamoorthy, Vinayagam Mohanavel, Thanikodi Sathish, Sinouvassane Djearamane, Palanivel Velmurugan, Alagar Karthick, Omaima Nasif, et al. "Thermal and Flame Retardant Behavior of Neem and Banyan Fibers When Reinforced with a Bran Particulate Epoxy Hybrid Composite." Polymers 13, no. 22 (November 9, 2021): 3859. http://dx.doi.org/10.3390/polym13223859.
Повний текст джерелаАнотація:
Awareness of environmental concerns influences researchers to develop an alternative method of developing natural fiber composite materials, to reduce the consumption of synthetic fibers. This research attempted testing the neem (Azadirachta indica) fiber and the banyan (Ficus benghalensis) fiber at different weight fractions, under flame retardant and thermal testing, in the interest of manufacturing efficient products and parts in real-time applications. The hybrid composite consists of 25% fiber reinforcement, 70% matrix material, and 5% bran filler. Their thermal properties—short-term heat deflection, temperature, thermal conductivity, and thermal expansion—were used to quantify the effect of potential epoxy composites. Although natural composite materials are widely utilized, their uses are limited since many of them are combustible. As a result, there has been a lot of focus on making them flame resistant. The thermal analysis revealed the sample B was given 26% more short-term heat resistance when the presence of banyan fiber loading is maximum. The maximum heat deflection temperature occurred in sample A (104.5 °C) and sample B (99.2 °C), which shows a 36% greater thermal expansion compared with chopped neem fiber loading. In sample F, an increased chopped neem fiber weight fraction gave a 40% higher thermal conductivity, when compared to increasing the bidirectional banyan mat of this hybrid composite. The maximum flame retardant capacity occurred in samples A and B, with endurance up to 12.9 and 11.8 min during the flame test of the hybrid composites.
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Jang, Joon-Hyeok, Seok-Bin Hong, Jin-Gyun Kim, Nam-Seo Goo, and Woong-Ryeol Yu. "Accelerated Testing Method for Predicting Long-Term Properties of Carbon Fiber-Reinforced Shape Memory Polymer Composites in a Low Earth Orbit Environment." Polymers 13, no. 10 (May 17, 2021): 1628. http://dx.doi.org/10.3390/polym13101628.
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Carbon fiber-reinforced shape memory polymer composites (CF-SMPCs) have been researched as a potential next-generation material for aerospace application, due to their lightweight and self-deployable properties. To this end, the mechanical properties of CF-SMPCs, including long-term durability, must be characterized in aerospace environments. In this study, the storage modulus of CF-SMPCs was investigated in a simulation of a low Earth orbit (LEO) environment involving three harsh conditions: high vacuum, and atomic oxygen (AO) and ultraviolet (UV) light exposure. CF-SMPCs in a LEO environment degrade over time due to temperature extremes and matrix erosion by AO. The opposite behavior was observed in our experiments, due to crosslinking induced by AO and UV light exposure in the LEO environment. The effects of the three harsh conditions on the properties of CF-SMPCs were characterized individually, using accelerated tests conducted at various temperatures in a space environment chamber, and were then combined using the time–temperature superposition principle. The long-term mechanical behavior of CF-SMPCs in the LEO environment was then predicted by the linear product of the shift factors obtained from the three accelerated tests. The results also indicated only a slight change in the shape memory performance of the CF-SMPCs.
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Bakošová, Dana, and Alžbeta Bakošová. "Testing of Rubber Composites Reinforced with Carbon Nanotubes." Polymers 14, no. 15 (July 27, 2022): 3039. http://dx.doi.org/10.3390/polym14153039.
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Carbon nanotubes (CNTs) have attracted growing interest as a filler in rubber nanocomposites due to their mechanical and electrical properties. In this study, the mechanical properties of a NR/BR/IR/SBR compound reinforced with single-wall carbon nanotubes (SWCNTs) were investigated using atomic force microscopy (AFM), tensile tests, hardness tests, and a dynamical mechanical analysis (DMA). The tested materials differed in SWCNT content (1.00–2.00 phr) and were compared with a reference compound without the nanofiller. AFM was used to obtain the topography and spectroscopic curves based on which local elasticity was characterized. The results of the tensile and hardness tests showed a reinforcing effect of the SWCNTs. It was observed that an addition of 2.00 phr of the SWCNTs resulted in increases in tensile strength by 9.5%, Young’s modulus by 15.44%, and hardness by 11.18%, while the elongation at break decreased by 8.39% compared with the reference compound. The results of the temperature and frequency sweep DMA showed higher values of storage and loss moduli, as well as lower values of tangent of phase angle, with increasing SWCNT content.
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Lin, Jeng-Shyong. "Effect of Heat Treatment on the Impact Strength of Glass Fibre Reinforced Polypropylene." Polymers and Polymer Composites 10, no. 8 (November 2002): 607–18. http://dx.doi.org/10.1177/096739110201000804.
Повний текст джерелаАнотація:
The improvement of the interfacial adhesion of glass fibre reinforced polypropylene composites by heat treatment was studied. Polypropylene blended with short glass fibres was injection moulded. The moulded specimens were heat treated at various temperatures and for various times. Characterization of the mechanical properties of the samples was performed, including measurement of the critical fibre length. Impact tests were performed. The fracture surfaces were examined using a scanning electron microscope. The results show that the impact strength increased with the testing temperature. At 25°C, the impact strength was dominated by the fibre fracture mechanism. At temperatures above 120°C, it was strongly influenced by the PP matrix. At higher temperatures, the impact strength increased significantly because of the formation of extra cracks.
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Lin, Jeng-Shyong. "Effect of Heat Treatment on the Tensile Strength of Glass Fibre Reinforced Polypropylene." Polymers and Polymer Composites 11, no. 5 (July 2003): 369–81. http://dx.doi.org/10.1177/096739110301100503.
Повний текст джерелаАнотація:
Improvement of the interfacial adhesion by heat treatment of glass fibre reinforced polypropylene composite was studied. Polypropylene blended with glass fibres was injection-molded. The molded parts were heat treated at various temperatures for various times. Characterization of the mechanical properties of the resulting samples was performed including measurement of the critical fibre length, and differential scanning calorimetry. The results show that the critical fibre length increases while the tensile strength decreases with increasing testing temperature. At 25 and 80°C, heat treatment can improve the tensile strength. At or above 120°C, certain treatment conditions cause the tensile strength to drop significantly.
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Valente, Bruno F. A., Armando J. D. Silvestre, Carlos Pascoal Neto, Carla Vilela, and Carmen S. R. Freire. "Improving the Processability and Performance of Micronized Fiber-Reinforced Green Composites through the Use of Biobased Additives." Polymers 14, no. 17 (August 24, 2022): 3451. http://dx.doi.org/10.3390/polym14173451.
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Green composites made of bioplastics reinforced with natural fibers have gained considerable attention over recent years. However, the use of natural fibers in composites usually compromise some key properties, such as the impact strength and the processability of the final materials. In the present study, two distinct additives, namely an epoxidized linseed oil (ELO) and a sugar-based surfactant, viz. GlucoPure® Sense (GPS), were tested in composite formulations of poly(lactic acid) (PLA) or poly(hydroxybutyrate) (PHB) reinforced with micronized pulp fibers. Both additives showed a plasticizing effect, which led to a decrease in the Young’s and flexural moduli and strengths. At the same time, the elongation and flexural strain at break were considerably improved on some formulations. The melt flow rate was also remarkably improved with the incorporation of the additives. In the PHB-based composites, an increment of 230% was observed upon incorporation of 7.5 wt.% ELO and, in composites based on PLA, an increase of around 155% was achieved with the introduction of 2.5 wt.% GPS. ELO also increased the impact strength to a maximum of 29 kJ m−2, in formulations with PLA. For most composites, a faster degradation rate was observed on the formulations with the additives, reaching, in the case of PHB composites with GPS, a noteworthy weight loss over 75% under burial testing in compost medium at room temperature.
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Chicos, Lucia-Antoneta, Mihai Alin Pop, Sebastian-Marian Zaharia, Camil Lancea, George Razvan Buican, Ionut Stelian Pascariu, and Valentin-Marian Stamate. "Fused Filament Fabrication of Short Glass Fiber-Reinforced Polylactic Acid Composites: Infill Density Influence on Mechanical and Thermal Properties." Polymers 14, no. 22 (November 17, 2022): 4988. http://dx.doi.org/10.3390/polym14224988.
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Fused Filament Fabrication (FFF) is one of the frequently used material extrusion (MEX) additive manufacturing processes due to its ability to manufacture functional components with complex geometry, but their properties depend on the process parameters. This paper focuses on studying the effects of process parameters, namely infill density (25%, 50%, 75%, and 100%), on the mechanical and thermal response of the samples made of poly(lactic acid) (PLA) reinforced with short glass fibers (GF) produced using FFF process. To perform a comprehensive analysis, tensile, flexural, compression, differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA) tests were used. The paper also aims to manufacture by FFF process of composite structures of the fuselage section type, as structural elements of an unmanned aerial vehicle (UAV), and their testing to compression loads. The results showed that the tensile, flexural and compression strength of the additive manufactured (AMed) samples increased with the increase of infill density and therefore, the samples with 100% infill density provides the highest mechanical characteristics. The AMed samples with 50% and 75% infill density exhibited a higher toughness than samples with 100% infill. DSC analyses revealed that the glass transition (Tg), and melting (Tm) temperature increases slightly as the infill density increases. Thermogravimetric analyses (TGA) show that PLA-GF filament loses its thermal stability at a temperature of about 311 °C and the increase in fill density leads to a slight increase in thermal stability and the complete degradation temperature of the AMed material. The compression tests of the fuselage sections manufactured by FFF made of PLA-GF composite showed that their stiffening with stringers oriented at an angle of ±45° ensures a higher compression strength than the stiffening with longitudinal stringers.
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Novais, Veridiana Resende, Paulo Cézar Simamotos Júnior, Regina Maria Puppin Rontani, Lourenço Correr-Sobrinho, and Carlos José Soares. "Bond strength between fiber posts and composite resin core: influence of temperature on silane coupling agents." Brazilian Dental Journal 23, no. 1 (2012): 08–14. http://dx.doi.org/10.1590/s0103-64402012000100002.
Повний текст джерелаАнотація:
This study evaluated the effect of air drying temperature and different silane coupling agents on the bond strength between glass fiber posts and composite resin core. The post surface was cleaned with alcohol and treated with different silane coupling agents, being three prehydrolyzed silanes [Silano (Angelus), Prosil (FGM), RelyX Ceramic Primer (3M ESPE)] and one two-component silane [Silane Coupling Agent (Dentsply)]. Two post-silanization air drying temperatures, 23ºC and 60ºC, were applied. A cylindrical plastic matrix was placed around the silanized post and filled with composite resin. Each bonded post provided 7 slices for push-out testing. Each slice was loaded to failure under compression at a cross-head speed of 0.5 mm/min. Data were analyzed by two-way ANOVA and Scott-Knott tests (α=0.05). Dunnett's test was used to compare the mean of the control group with that of each experimental group. Scanning electron microscopy (SEM) was used to evaluate the interface of the fractured slices. For the 23ºC air drying temperature, the use of RelyX Ceramic Primer resulted in significantly lower bond strength than the other silane coupling agents, while the bond strength with Silane Coupling Agent was the highest of all groups. Only with Silane Coupling Agent, the bond strength for the 23ºC air drying temperature was significantly higher than that for 60ºC air drying. In conclusion, the use of warm air drying after silane application produced no increase in the bond strength between the fiber-reinforced composite post and the composite core. The two-component silane produced higher bond strength than all prehydrolyzed silanes when it was used with air drying at room temperature.
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Hamada, H., S. Ramakrishna, and H. Sato. "Effect of Testing Temperature on the Energy Absorption Behavior of Carbon Fiber/PEEK Composite Tubes." Journal of Reinforced Plastics and Composites 15, no. 1 (January 1996): 30–47. http://dx.doi.org/10.1177/073168449601500103.
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Muna, Isyna Izzal, Magdalena Mieloszyk, Ruta Rimasauskiene, Nabeel Maqsood, and Marius Rimasauskas. "Thermal Effects on Mechanical Strength of Additive Manufactured CFRP Composites at Stable and Cyclic Temperature." Polymers 14, no. 21 (November 2, 2022): 4680. http://dx.doi.org/10.3390/polym14214680.
Повний текст джерелаАнотація:
Additive manufacturing (AM) techniques can be applied to produce carbon-fiber-reinforced polymer (CFRP) elements. Such elements can be exposed to different environmental factors, e.g., temperature, moisture, and UV radiation, related to their operational conditions. From a variety of environmental factors, the temperature is one of the most typical. Temperature strongly influences matrix material joining together CFRP components, resulting in material strength reduction. Therefore, it is important to understand processes in the composite material caused by temperature. This experimental work investigated the thermal effects on the performances of AM CFRP composites. Specimens with unidirectional (UD) alignments of the fiber reinforcement were printed using the fused deposition modeling (FDM) technique. The printed specimens were subjected to two different thermal conditions: stable continuous at 65 ∘C and cyclic temperature between 50 and 70 ∘C. Tensile testing was performed to study the mechanical strength and Young’s modulus of AM UD-CFRPs. In order to investigate the morphological structure on the surface of AM specimens, an optical microscope, scanning electron microscope (SEM), and digital microscope were utilized. Untreated (intact) samples attained the highest average tensile strength value of 226.14 MPa and Young’s modulus of 28.65 GPa. The ultimate tensile strength of the sample group subjected to stable heat treatment decreased to 217.99 MPa, while the thermal cycling group reduced to 204.41 MPa. The Young’s modulus of the sample group subjected to stable thermal exposure was decreased to 25.39 GPa, while for the thermal cycling group, it was reduced to 20.75 GPa. The visual investigations revealed that the intact or untreated specimen group exhibited lateral damage in top failure mode (LAT), the thermally stable group underwent edge delamination in the middle (DGM) as the nominated failure mode, and the explosive breakage at gauge in the middle (XGM) failure mode occurred in the sample from the thermal cycling group. Based on morphological observations at the microscale, the delamination, fiber pull-out, and matrix cracking were the dominant damages in the 3D-printed tensile-tested specimens. The molecular chains of the polymer changed their structure into an amorphous one, and only local motions of stretching occurred when the specimens were exposed to stable heating (prolonged). In the case of thermal cycling, the strain gradients were accumulated in the matrix material, and the local stresses increased as a result of the reheating and re-cooling exposure of the polymeric composites; the molecular motion of the long-range polymer structure was reactivated several times. Micro-cracking occurred as a result of internal stresses, which led to material failure and a reduction of the mechanical properties.
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Chokka, Syam Kumar, B. Satish Ben, and KV Sai Srinadh. "Parametric optimization for rehabilitation of pipes with adhesive bonding." High Performance Polymers 32, no. 5 (November 29, 2019): 588–99. http://dx.doi.org/10.1177/0954008319889091.
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This work deals with the optimization of process parameters for rehabilitation of the pipe through-wall hole defects using adhesive bonding. Epoxy-based nonstructural adhesive (NSA) and structural adhesive (SA) combination, precure temperature, bond length, and surface preparation were considered as the parameters. The optimization of parameters directly on pipes is an expensive and time-consuming process. Hence, stainless steel and carbon fiber-reinforced polymer (SS-CFRP) composite single-strap joint was considered. The equivalent loads that were acting during the hydrostatic pressure test were applied to the SS-CFRP joint and its parametric effect on bond strength was studied. The stress distribution along the adhesive layer length has been derived analytically. The surface roughness of prebond surfaces was measured using a 3-D microscope. The quality of the adhesive bond was evaluated using nondestructive testing (digital radiography). The damaged pipe was rehabilitated with optimized parameters and its hydrostatic pressure resistance was tested according to ISO/TS 24817 standards. From the results, it is observed that the rehabilitated pipe with optimized parameters was able to sustain a maximum of 79% of its allowable pressure.
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Pisanu, Luciano, Leonardo Costa Santiago, Josiane Dantas Viana Barbosa, Valter Estevão Beal, and Marcio Luis Ferreira Nascimento. "Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding." Polymers 13, no. 7 (March 26, 2021): 1039. http://dx.doi.org/10.3390/polym13071039.
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The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP–coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP–coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.
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Gohel, Goram, Chun Zhi Soh, Kah Fai Leong, Pierre Gerard, and Somen K. Bhudolia. "Effect of PMMA Coupling Layer in Enhancing the Ultrasonic Weld Strength of Novel Room Temperature Curable Acrylic Thermoplastic to Epoxy Based Composites." Polymers 14, no. 9 (May 2, 2022): 1862. http://dx.doi.org/10.3390/polym14091862.
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The joining of composites can be performed in an extremely short time with more energy-efficient ultrasonic welding techniques. The current research investigated the performance optimization of ultrasonic welding of carbon/Elium® composite to carbon/epoxy composite using a polymethyl methacrylate (PMMA) coupling interlayer. The weld strength was quantified by static lap shear strength (LSS) testing. A new methodology was used by creating a PMMA coupling layer on the epoxy composite adherend to achieve an improved interphase and thus enhance the weld properties. The LSS of Elium (EL)-Epoxy (EP) _0.25_0.25 was found to be 190% higher compared to that of EL-EP, confirming the effectiveness of the strategy used for creating an interlayer thermoplastic coupling layer. The time required for welding was optimized to be 2s as compared to 10 min required for adhesive bonding. Scanning electron microscopic images of epoxy and PMMA/Elium matrix interphase were observed to have a rough surface and remained largely unaffected by welding. There was an interphase change further away from the interphase to a rougher texture. There was little to no effect on the penultimate layer on the weld strength, as no interphase change could be observed after welding. Fractography investigation revealed shear cusps, matrix plastic deformation, fiber imprints, fiber pull-out, and good adhesion between matrix and fiber, features seen for configuration with maximum LSS. The current research findings present a way to join Elium® with epoxy composites that could be used in applications that require a selective strengthening, such as in sporting goods and consumer products. Furthermore, a detailed investigation is ongoing to use different filler particles and coupling layers to reach the maximum welding performance.
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Gregory, Shawn Alan, Keshav Swarup, Christopher Lo, Ryan Dwyer, Michael Davidson, Timothy Monroe, Colten Spivey, and Mary Lynn Realff. "Understanding thermomechanical failure of athletic textiles via the pendulum skid method." Textile Research Journal 89, no. 10 (June 11, 2018): 1825–34. http://dx.doi.org/10.1177/0040517518779994.
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Fiber textiles worn by some athletes and basketball and volleyball players experience higher than usual thermomechanical stresses compared to everyday garments because these athletes slide and dive on hardwood courts. Common textile testing procedures, such as the Martindale abrasion tester, effectively test textiles under modest loads and thousands of cycles, but this methodology does not suffice for athletic textiles. In addition, there is not a robust model nor a repeatable test that mimics high thermomechanical stress on fabrics and provides insights on fabric abrasion resistance. We present a model to calculate the temperatures and strain rates that are seen by fabrics undergoing thermomechanical deformation. To enable validation of the model, a fabric pendulum abrasion tester, an adaptation of the Cooper pendulum skid tester, was developed. The tester characterizes high-strain fabric abrasion deformation. This adaptation is statistically reliable and induces repeatable and realistic fabric failure within tens to hundreds of cycles, proving to be analogous to the loads athletes place on their textiles. Analog electronics on the pendulum abrasion tester generate real-time temperature and velocity profiles. A series of 11 unique athletic fabrics were abrasion tested, and it was found that fabrics with macroporosity experience the largest abrasion degradation. Significant degradation sites were further explored using scanning electron microscopy and X-ray diffraction analysis, and it was shown that thermomechanical loading’s effect on fiber microstructure is a function of the fabric construction. This novel abrasion tester and quantitative relationships between fabric structure and degradation mechanisms will enable more data-driven decisions when designing textiles for thermomechanical loads.
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Singh, Daler, and Sukhjinder Singh Sandhu. "Effect of Laser Power on Component Strength in Laser Sintering." International Journal of Advance Research and Innovation 4, no. 1 (2016): 162–67. http://dx.doi.org/10.51976/ijari.411625.
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Prototyping or model making is one of the important steps to finalize a product design. It helps in conceptualization of a design. Before the start of full production a prototype is usually fabricated and tested. RP processes namely Stereo-lithography (SL), Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM) and Laminated Object Manufacturing (LOM) are described. In Selective Laser Sintering (SLS) process, fine polymeric powder like polystyrene, polycarbonate or polyamide etc. (20 to 100 micrometer diameter) is spread on the substrate using a roller. Before starting CO2 laser scanning for sintering of a slice the temperature of the entire bed is raised just below its melting point by infrared heating in order to minimize thermal distortion (curling) and facilitate fusion to the previous layer. The laser is modulated in such a way that only those grains, which are in direct contact with the beam, are affected. Once laser scanning cures a slice, bed is lowered and powder feed chamber is raised so that a covering of powder can be spread evenly over the build area by counter rotating roller. In this process support structures are not required as the un-sintered powder remains at the places of support structure. It is cleaned away and can be recycled once the model is complete. This research has examined the effect of Laser power as well as processing parameters on the mechanical properties of selective laser sintered parts from DURAFORM PA In this research tensile specimens of Polyamide (DURAFORM PA) material as per the test standard ‘ASTM D638’ are fabricated. This test method covers the determination of the tensile properties of unreinforced and reinforced plastics in the form of standard dumbbell-shaped test specimens when tested under defined conditions of pre-treatment, temperature, humidity, and testing machine speed. The effects of varying the Laser power, generated by the laser, on the physical and mechanical properties of produced specimens. The energy density is varied by changing the laser power at a fixed value of laser scan spacing. Knowing the relationship between SLS parameter settings and material properties will make it possible to manufacture parts with predetermined properties, customized for various applications.
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Mashayekhi, Fatemeh, Julien Bardon, Stephan Westermann, and Frédéric Addiego. "Adhesion Optimization between Incompatible Polymers through Interfacial Engineering." Polymers 13, no. 24 (December 7, 2021): 4273. http://dx.doi.org/10.3390/polym13244273.
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Additive manufacturing technologies such as fused filament fabrication (FFF) open many possibilities in terms of product functionality, including the possibility to integrate a sensor in FFF parts to perform structural health monitoring. In this context, embedding fiber Bragg grating (FBG) sensors into 3D-printed polymeric structures for strain or temperature measurements has attracted increasing attention in recent years. Indeed, offering structural health monitoring functionality can optimize the maintenance cost and increase security compared with conventional materials. However, the transmission of strain and temperature between the polymeric matrix and the FBG polymer jacket requires optimal bonding between them. In this work, the two polymers of interest are polyimide (PI) and poly(lactic acid) (PLA) for the FBG jacket and printed polymer, respectively. The current study investigates the influence of different surface treatment methods on the adhesion between a PI film and a plate of PLA, with PLA and PI being incompatible polymers. The adhesion promotion applied to the PI surface relies on cleaning, plasma activation, roughness modification, or the use of adhesive nanocoating. Bilayer samples of PI-PLA are processed by welding PLA against the treated PI by heating, whereas the adhesion between PI and PLA is measured by peel testing. It is observed that the highest adhesion between PI and PLA is achieved by a combination of mechanical abrasion increasing roughness and the use of polydopamine as an adhesive. This finding is discussed based on a synergetic effect between mechanical interlocking and chemical interaction between the two counterfaces.
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Yongfu, Xu, and Yi Zhang. "Study on modification of rabbit hair fibers with L-cysteine." Textile Research Journal 90, no. 13-14 (December 3, 2019): 1628–38. http://dx.doi.org/10.1177/0040517519891449.
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Rabbit hair fibers were modified by L-cystine under the action of ultrasound and a kind of modified rabbit hair fiber was obtained. An orthogonal test of four factors and three levels was designed. The range analysis was analyzed using a comprehensive score method of friction factor and fiber strength, and the variance analysis was carried out by Statistical Package for Social Science statistical software. The optimal modification conditions were obtained: a concentration of L-cystine (A) of 0.05 mol/L, ultrasonic power (B) of 90 W, a water bath temperature (C) of 75℃, and ultrasonic treatment time (D) of 1 hour. Univariate analysis showed the L-cystine concentration had the most significant effect on the modification of rabbit hair fibers, and the regression equation is y = 74.423 + 1300.267 A−1.818 C−9092A2 + 0.019C2. The surface brightness of the modified rabbit hair fibers was enhanced and the scale angle was increased 20° by setting up the angle of the scale model and the electron microscope. The internal structure of rabbit hair fibers was characterized by Fourier transform infrared spectroscopy, peak separation, and differential scanning calorimetry. The results showed that L-cystine reduced the disulfide bond in the macromolecular chain by 3%, resulting in a change in the secondary structure of the rabbit hair, a decrease in the α-helix structure content, and an increase in β-folding structure content. Ellman’s reagent was used to determine that the content of the sulfhydryl group consumed in the modification was 0.211 mol/L. Testing the dye adsorption capacity and spinnability (adding 20%) of modified rabbit hair fibers showed an obvious improvement.
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Widyotomo, Sukrisno. "Performance of a Big Scale Green House Type Dryer for Coffee Drying Process." Pelita Perkebunan (a Coffee and Cocoa Research Journal) 30, no. 3 (December 30, 2014): 240–57. http://dx.doi.org/10.22302/iccri.jur.pelitaperkebunan.v30i3.69.
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Dying is one of important steps in coffee processing to produce good quality. Greenhouse is one of artificial drying alternatives that potential for coffee drying method cause of cleans environmental friendly, renewable energy sources and chippers. Indonesian Coffee and Cocoa Research Institute has developed and testing a big scale greenhouse type dryer for fresh coffee cherries and wet parchment coffee drying process. Greenhouse has 24 m length, 18 m width, also 3 m high of the front side and 2 m high of the rear side. The maximum capacity of greenhouse is 40 tons fresh coffee cherries. Fiber Reinforced Plastic (FRP) used as greenhouse roof that combined with I and C profile of steel. Fresh coffee cherries and wet parchment coffee from Robusta variety use as main materials in this research. The treatment of this research was 30 kg/m2, 60 kg/m2 and 90 kg/m2 for coffee density. String process has done by manual, two times a day in the morning and in the afternoon. As control, fresh coffee cherries and wet parchment coffee has dried by fully sun drying method. The result showed that a big scale greenhouse has heat drying efficiency between 29.9-58.2% depend on type and density of coffee treatments. On the full sunny day, greenhouse has produced maximum drying air temperature up to 52oC. In radiation cumulative level 4-5 kW-jam/m2 per day, 12.9-38.8 tons fresh coffee cherries or wet parchment coffee with 58-64% moisture content can be dried to 12% moisture content for 6 up to 14 days drying process. Slowly drying mechanism can be avoided negative effect to degradation of quality precursor compound. Capacity of the dryer can be raise and fungi can be reduce with application of controllable mechanical stirring in the greenhouse. Keywords: greenhouse, coffee, drying, quality
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Wang, Yongqiang, Changhui Feng, Ruoyu Fei, and Yu Luo. "Thermal-ageing characteristics of dry-type transformer epoxy composite insulation." High Performance Polymers 32, no. 7 (February 26, 2020): 741–52. http://dx.doi.org/10.1177/0954008320906439.
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To study the ageing characteristics of epoxy resin composite insulation in dry-type transformers in high-temperature environments, glass fibre-reinforced epoxy resin samples were placed in a hot air ageing environment at 130°C for testing. Dielectric properties, partial discharge (PD), microscopic morphology, three-dimensional morphology and Fourier transform infrared spectroscopy of aged samples were periodically tested. The results show that during the ageing process, the change in the surface morphology of the sample leads to an overall upward trend in surface roughness, and the older the sample, the faster the surface roughness increases; changes in the surface morphology and three-dimensional morphology of the material constitute the basis for judging the condition of the insulating surface and the state of ageing development. Microcracks are the direct cause of debonding of glass fibres and epoxy matrix. Degradation of the sample during the ageing process generates many free radicals, which enhances the polarisation ability of the sample and increases both the dielectric constant and the dielectric loss factor. The real part of the complex dielectric constant is more sensitive to the ageing response of the sample. The older the sample, the greater the effect on the results of the dielectric spectrum test. Since the aged sample generates more hot electrons during the PD process and makes it easier to inject electrons into the material, the PD of the sample is rendered more intense by thermal ageing. There is a significant difference between the degradation mechanism of the thermal ageing and PD. The samples subjected to PD after thermal ageing produce new groups, and the degradation of the samples is more severe than that caused by thermal ageing, or PD, alone.
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Siddikali, Palaiam, and P. S. Rama Sreekanth. "Performance Evaluation of CNT Reinforcement on Electroless Plating on Solid Free-Form-Fabricated PETG Specimens for Prosthetic Limb Application." Polymers 14, no. 16 (August 18, 2022): 3366. http://dx.doi.org/10.3390/polym14163366.
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The utility of polymers in the present decade is consistently increasing, giving scope to many applications from automobiles to prosthetics. Polymers used for solid free-form fabrication (SFFF), also known as 3D printing, comprise a quick fabrication process adopted by many industries to increase productivity and decrease the run time to cope with the market demands. In this research work, pure polyethylene terephthalate glycol (PETG) and multi-walled carbon nanotube (MWCNT)-PETG with an electroless metal layer coating and without a coating are discussed. The effect of the electroless metal layer coating on the reinforced PETG-MWCNT results in improved mechanical, tribological, and other surface properties. Pure PETG was incorporated with MWCNT nanofillers at 0.3 wt.% and extruded as a filament through a twin screw extruder with a 1.75 mm diameter and printed on ASTM standards. Tensile testing was performed on all four types of un-coated pure PETG, PETG-MWCNT, and metal-layer-coated PETG and PETG-MWCNT with a coating thickness of 26, 32, 54, and 88 μm. Dynamic mechanical analysis (DMA) showed that the coated PETG-MWCNT had the highest storage and loss modulus. The heat deflection temperature was improved to 88 °C for the coated PETG-MWCNT. The wear volume against the sliding distance at a load of 40, 50, and 60 N showed that the coefficient of friction decreased with an increase in the load. The scratch test results revealed the lowest penetration depth and lowest friction coefficient for the coated PETG-MWCNT sample. The water contact angle test showed that a greater coating thickness makes the sample surface more hydrophobic, and the microhardness test indicated that the indentation hardness value for the PETG-MWCNT was 92 HV. The study revealed that the metal-layer-coated PETG-MWCNT had better performance compared to the other specimens due to a good metal layer bonding on the PETG substrate. It was concluded that adding MWCNTs to a metal layer electroless coating improved the surface and mechanical properties of the PETG, and this may be suitable for many applications.
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Li, Zhaoqian, Xiaodong Zhou, and Chonghua Pei. "Effect of Sisal Fiber Surface Treatment on Properties of Sisal Fiber Reinforced Polylactide Composites." International Journal of Polymer Science 2011 (2011): 1–7. http://dx.doi.org/10.1155/2011/803428.
Повний текст джерелаАнотація:
Mechanical properties of composites are strongly influenced by the quality of the fiber/matrix interface. The objective of this study was to evaluate the mechanical properties of polylactide (PLA) composites as a function of modification of sisal fiber with two different macromolecular coupling agents. Sisal fiber reinforced polylactide composites were prepared by injection molding, and the properties of composites were studied by static/dynamic mechanical analysis (DMA). The results from mechanical testing revealed that surface-treated sisal fiber reinforced composite offered superior mechanical properties compared to untreated fiber reinforced polylactide composite, which indicated that better adhesion between sisal fiber and PLA matrix was achieved. Scanning electron microscopy (SEM) investigations also showed that surface modifications improved the adhesion of the sisal fiber/polylactide matrix.
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Li, Baoan, and Han Han Fan. "A High-Performance Heat Exchanger Using Modified Polyvinylidene Fluoride-Based Hollow Fibers." Advanced Materials Research 479-481 (February 2012): 115–19. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.115.
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Plastic heat exchangers has the shortcomings of bulky, thick pipe wall with large thermal resistance, poor heat transfer, aging of plastic and a narrow temperature range. The key to increase the heat transfer performance of heat exchanger is improving thermal performance of heat conduction.To enhance heat transfer effects and expand the temperature range of using plastic heat exchanger, PVDF with good temperature resistance is used as matrix and modification with graphite fillers to prepare composite hollow fiber which has the advantage of small diameter, thin wall and good thermal conductivity. Also, composite materials hollow fibers are used to prepare shell and tube hollow fiber heat exchanger.The testing of "water - water" system for our heat exchanger module has been done, and the results indicate that adding graphite is helpful to improve thermal conductivity of PVDF-based heat conductive hollow fiber heat exchanger to a certain extent.hen the content of graphite is 3%, the heat transfer effect is the best.
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Bazhenov, S. L., and A. A. Berlin. "Temperature effect on fracture mechanisms in organic-fiber-reinforced plastics under compression." Doklady Physics 46, no. 7 (July 2001): 488–90. http://dx.doi.org/10.1134/1.1390403.
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M J, Raghu, and Govardhan Goud. "Effect of Water Absorption on Mechanical Properties of Calotropis Procera Fiber Reinforced Polymer Composites." Journal of Applied Agricultural Science and Technology 4, no. 1 (February 28, 2020): 3–11. http://dx.doi.org/10.32530/jaast.v4i1.137.
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The present work investigates the effect of water absorption on mechanical properties of calotropis procera fiber reinforced epoxy polymer composites. The calotropis procera fiber chemical and mechanical testing was done to evaluate chemical composition and strength of the fiber. The composites are fabricated by reinforcing calotropis procera fiber in epoxy matrix by varying the fiber wt. % by traditional hand layup method. The water absorption of calotropis procera reinforced epoxy polymer composites at room temperature was found to increase with increasing fiber loading. The mechanical testing results of moisture exposed composites indicated decreased strength which may be due to degraded bonding between fiber and matrix.
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Onitiri, M. A., and S. M. Adedayo. "Compressive behaviour of polypropylene filled with iron ore tailings." Journal of Engineering, Design and Technology 13, no. 2 (May 5, 2015): 198–212. http://dx.doi.org/10.1108/jedt-12-2012-0056.
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Purpose – This paper aims to produce iron ore tailings reinforced polypropylene composites (ITR-PPCs) from conventional compo-casting (CC) and a proposed compo-indirect squeeze casting (C-ISC) processes. It intends to quantify the compressive behaviour of ITR-PPC with respect to production process, iron ore tailings volume and particle size inclusion in polypropylene (PP) through controlled material and compressive testing. The study aims to provide useful information on possibility of the use of ITR-PP for compressive applications which will culminate to judicious use of iron ore tailings that is been piled up as waste material at the iron ore beneficiation sites. Design/methodology/approach – ITR-PPC compression specimens were produced using C-ISC and CC processes. Prior to production, the iron ore tailings was dried at room temperature according to ASTM 618, ASTM 171 and ASTM E 41. The different particle sizes were generated using standard laboratory sieves. Uniaxial compressive test procedure according to ASTM D 695 was carried out on ITR-PPC compression specimens with length/diameter ratio equal to 2.0 under standard laboratory atmosphere on an Instrom 3,369 machine. Findings – It was discovered that pure PP produced using the C-ISC process exhibited better compressive strength and Young’s modulus of about 12 and 4.5 per cent, respectively, while a reduction of 9.2 per cent in yield strength was recorded. ITR-PPCs with 150-μm fillers produced from C-ISC process have lower yield stress, compressive strength and Young’s modulus at volume contents above 10 per cent. It also exhibited lower strain at fracture at volume content above 15 per cent, while composites filled with 212- and 300-μm particle size iron ore tailings using the C-ISC process had better strain at fracture. Research limitations/implications – The present work cannot ascertain the compressive behaviour of ITR-PPC produced from other production processes, hence the need for further work in this area. Practical implications – The paper provides an avenue to address the pollutant effect of iron ore tailings by putting it to judicious use through addition as fillers in plastics. It also removes the need for expensive and repeated experimentation to determine the compressive behaviour of ITR-PPCs. Originality/value – This paper has brought to fore the need to study iron ore tailings as filler in plastics and other material matrices.
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Guo, Fucheng, Rui Li, Shuhua Lu, Yanqiu Bi, and Haiqi He. "Evaluation of the Effect of Fiber Type, Length, and Content on Asphalt Properties and Asphalt Mixture Performance." Materials 13, no. 7 (March 27, 2020): 1556. http://dx.doi.org/10.3390/ma13071556.
Повний текст джерелаАнотація:
Fiber-reinforced asphalt mixture has been widely used in pavement engineering to not only prevent asphalt binder leakage but also improve engineering properties of asphalt mixture. However, the research on three key parameters, namely fiber type, fiber length, and fiber content, which significantly affect the performance of fiber-reinforced asphalt mixture, have seldom been conducted systematically. To determine these three key parameters in the support of the application of fibers in mixture scientifically, three commonly used fibers were selected, basalt fiber, polyester fiber, and lignin fiber, and the testing on fibers, fiber-reinforced asphalt binders, and fiber-reinforced asphalt mixtures was conducted afterwards. The results showed: the favorable fiber type was basalt fiber; the favorable basalt fiber length was 6mm; the engineering properties including high temperature stability, low temperature crack resistance, and water susceptibility were clearly improved by the added basalt fiber, and the optimum basalt fiber content was 0.4 wt.%. The obtained results may be valuable from a practical point of view to engineers and practitioners.
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Gao, Hang, H. L. Ma, Yong Jie Bao, H. P. Yuan, and Ren Ke Kang. "Theoretical Analysis of Grinding Temperature Field for Carbon Fiber Reinforced Plastics." Advanced Materials Research 126-128 (August 2010): 52–57. http://dx.doi.org/10.4028/www.scientific.net/amr.126-128.52.
Повний текст джерелаАнотація:
A three-dimensional finite difference method (FDM) model of grinding temperature field for carbon fiber reinforced plastics (CFRP) was established, based on the homogenization of the thermal properties of the CFRP material. The effect of the fiber direction on grinding temperature distribution at different workpiece velocity was numerically simulated and analyzed. It is found that the effect of the fiber direction on grinding temperature field is remarkable in lower workpiece velocity but unapparent in higher workpiece velocity due to the anisotropy of CFRP material and the velocity of moving heat source. More than 230 °C surface grinding temperature, which will badly damage CFRP performance, may be produced in dry grinding according to the simulated analysis. During grinding the heat affected zone of CFRP is about 0.22 mm in depth direction. Furthermore, experimental results are well in agreement with those of the theoretical analysis.
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Unal, Engin. "Temperature and thrust force analysis on drilling of Glass fiber reinforced plastics." Thermal Science 23, no. 1 (2019): 347–52. http://dx.doi.org/10.2298/tsci180117181u.
Повний текст джерелаАнотація:
Composite materials are widely used today in many sectors. Glass fiber reinforced plastic composite materials are one of those. Glass fiber reinforced plastic composite materials are preferred due to their high thermal and tensile strength. Although consist of glass fiber reinforced composite materials from multiple layers reduces the machinability of these materials, drilling is a common method of machining for these materials. However, when the drilling parameters are not carefully selected, the material integrity is deteriorated and the desired drilling quality cannot be obtained. In this study, the effect of drilling temperature and thrust force on the material integrity was investigated. The drill bit angle, spindle speed and feedrate parameters are used for the temperature and thrust force analysis.
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Jacobson, Kohl, Sam Strassler, Courtney Spalt, Sara Henry, Arthur Powers, and Donald W. Radford. "Effect of Fiber/Matrix Interface Modification on Basalt Fiber Reinforced Geopolymer Composites." Recent Progress in Materials 3, no. 1 (December 22, 2020): 1. http://dx.doi.org/10.21926/rpm.2101008.
Повний текст джерелаАнотація:
Continuous fiber reinforced geopolymer matrix composites offer the potential for use in structural applications at temperatures up to 700°C, while enabling the manufacture at temperatures below 100°C. Studies have investigated a variety of high temperature structural fiber reinforcements, including carbon, SiC and Al2O3. While there has been active research into various grades of Al2O3 fibers, SiC is most commonly used for high temperature reinforcement of geopolymers in oxidizing environments. Both families of reinforcement are relatively expensive and are capable of use temperatures which exceed those of the geopolymer. Basalt fibers have the potential to be a good match for the geopolymer matrix, both in terms of upper use temperature and cost. In this study, Basalt fabric reinforced geopolymer composites were prepared with fibers having three different surface conditions, as-received (silane sized), cleaned, and carbon-coated, to investigate the effect of fiber-matrix interface on the mechanical properties. All specimens were fabricated, cured at 80°C and conditioned at 250°C for 5 hours to create the baseline specimens. More than half of the 70 specimens manufactured were exposed to an additional 5 hours at 650°C. Flexural strength, strain-to-failure and modulus were determined at ambient temperature via 4-point bend testing. The as-received and cleaned specimens showed moduli approaching theoretical predictions, indicating a strong interfacial bond, resulting in brittle failures at low loads. The carbon coating resulted in a three-fold increase in strength after the 250°C conditioning and retained a strength higher than the other specimens, even after the 650°C treatment. This strength increase did come with a reduced modulus, suggesting that the stress transfer between fiber and matrix in the carbon-coated basalt fiber reinforced geopolymer composites had also been reduced. While the carbonaceous interphase was not expected to be stable at the higher temperatures in an oxidizing environment, the results do indicate that significant Basalt fiber reinforced geopolymer strength gains are possible through the implementation of a tailored fiber/matrix interface as a crack blunting mechanism.
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Ashir, Moniruddoza, and Chokri Cherif. "Development of shape memory alloy-based adaptive fiber-reinforced plastics by means of open reed weaving technology." Journal of Reinforced Plastics and Composites 39, no. 15-16 (April 21, 2020): 563–71. http://dx.doi.org/10.1177/0731684420920941.
Повний текст джерелаАнотація:
The functionalization of fiber-reinforced plastics has been improved continuously in recent years in order to broaden their application potential. By using shape memory alloys in fiber-reinforced plastics, adaptive fiber-reinforced plastics can be developed, which in turn can change their shape depending on the activation of shape memory alloys. In order to ensure the proper force transmission from shape memory alloys to fiber-reinforced plastic, these shape memory alloys need to be integrated into the reinforcing fabric. Hence, this paper presents the application of open reed weaving technology for the development of functionalized preforms for adaptive fiber-reinforced plastics. For an optimized shape memory effect during their thermal induced activation, the shape memory alloys were coated with release agent and then integrated into the woven fabric by open reed weaving technology. The hinged width of functionalized preforms was varied from 50 mm to 150 mm. These preforms were infused by a thermosetting resin matrix system with a modifier. Subsequently, the electro-mechanical testing of adaptive fiber-reinforced plastics was executed. Results show that the maximum deformation of adaptive fiber-reinforced plastics was proportional to their hinged width.
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Kwon, Junbeom, Jaeyoung Choi, Hoon Huh, and Jungju Lee. "Evaluation of the effect of the strain rate on the tensile properties of carbon–epoxy composite laminates." Journal of Composite Materials 51, no. 22 (December 12, 2016): 3197–210. http://dx.doi.org/10.1177/0021998316683439.
Повний текст джерелаАнотація:
This paper is concerned with evaluation and prediction of the tensile properties of carbon fiber-reinforced plastics laminates considering the strain rate effect at intermediate strain rates. Uniaxial tensile tests of carbon fiber-reinforced plastics laminates were conducted at various strain rates ranging from 0.001 s–1 to 100 s–1 using Instron 8801 and a high speed material testing machine to measure the variation of the elastic modulus and the ultimate tensile strength. Tensile test specimens were designed based on the ASTM standards and stacked unidirectionally such as [0°], [90°] and [45°] to predict the elastic modulus of carbon fiber-reinforced plastics laminates with various stacking sequences. The axial strain was measured by the digital image correlation method using a high speed camera and ARAMIS software to enhance the accuracy of the strain measurement. A prediction model of the elastic modulus of carbon fiber-reinforced plastics laminates is newly proposed in consideration of the laminate theory and the tensile properties of unidirectional carbon fiber-reinforced plastics laminates. The prediction model was utilized to predict the tensile properties of [0°/90°]s laminates, [±45°]s laminates, and [0°/±45/90°]T laminates for validation of the model. The elastic moduli predicted were compared with the static and dynamic tensile test results to confirm the accuracy of the prediction model.
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Koutsomichalis, Aggelos, Thomas Kalampoukas, and Dionysios E. Mouzakis. "Mechanical Testing and Modeling of the Time–Temperature Superposition Response in Hybrid Fiber Reinforced Composites." Polymers 13, no. 7 (April 6, 2021): 1178. http://dx.doi.org/10.3390/polym13071178.
Повний текст джерелаАнотація:
The purpose of this study was to manufacture hybrid composites from fabrics with superior ballistic performance, and to analyze their viscoelastic and mechanical response. Therefore, composites in hybrid lay-up modes were manufactured from Vectran, Kevlar and aluminum fiber-woven fabrics through a vacuum assisted resin transfer molding. The specimens were consequently analyzed using static three-point bending, as well as by dynamic mechanical analysis (DMA). Apart from DMA, time–temperature superposition (TTS) analysis was performed by all available models. It was possible to study the intrinsic viscoelastic behavior of hybrid ballistic laminates, with TTS analysis gained from creep testing. A polynomic mathematical function was proposed to provide a high accuracy for TTS curves, when shifting out of the linearity regimes is required. The usual Williams–Landel–Ferry and Arrhenius models proved not useful in order to describe and model the shift factors of the acquired curves. In terms of static results, the highly nonlinear stress–strain curve of both composites was obvious, whereas the differential mechanism of failure in relation to stress absorption, at each stage of deformation, was studied. SEM fractography revealed that hybrid specimens with Kevlar plies are prone to tensile side failure, whereas the hybrid specimens with Vectran plies exhibited high performance on the tensile side of the specimens in three-point bending, leading to compressive failure owing to the high stress retained at higher strains after the maximum bending strength was reached.
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Lee, Cheong Cheon, and Akira Shimamoto. "Control Effect on Fatigue Crack Propagation of TiNi Fiber Reinforced PMMA Composites." Key Engineering Materials 297-300 (November 2005): 2929–0. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2929.
Повний текст джерелаАнотація:
In this paper, the TiNi fiber reinforced/PMMA (Poly methyl methacrylate) composite is developed, and its effectiveness of controlling fatigue crack growth is studied. The TiNi fiber reinforced/PMMA composite’s mechanical property enhancement and deformation resistance are also studied. The fatigue behavior and crack propagation are observed with a SEM servo-pulser (fatigue testing instrument with scanning electron microscope) while increasing temperature. As the results, it is confirmed that the fatigue life and resistance are improved. How the shape memory effect and expansion behavior of the matrix caused by temperature increasing affect the fatigue crack propagation control is examined. It is verified that the control of fatigue crack growth is attributed to the compressive stress field in the matrix due to shrinkage of the TiNi fibers above austenitic finishing temperature (Af).
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Kudrin, A. M., K. S. Gabriel’s, and O. A. Karaeva. "The Temperature Effect on Mechanical Properties of Carbon Fiber Reinforced Plastics for Aviation Purposes." Inorganic Materials: Applied Research 9, no. 4 (July 2018): 763–66. http://dx.doi.org/10.1134/s2075113318040196.
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Xue, Di, Jin Bo Zhang, and Cai Hua Li. "Analysis of Influencing Factors of Ultrasonic Nondestructive Testing with Carbon Fiber Reinforced Plastics." Advanced Materials Research 430-432 (January 2012): 41–44. http://dx.doi.org/10.4028/www.scientific.net/amr.430-432.41.
Повний текст джерелаАнотація:
In order to research the influenced factors of sensitivity of ultrasonic nondestructive testing, the compared experiments using water immersion and contact method were carried out and the experimental results of sensitivities were obtained. The results showed that the limited sensitivities of probes with 1MHz and 2.25 MHz is very low. And the defects ofφ1mm, which distance not exceeding 1mm, can be detected by probes of 5 MHz and 10 MHz. The defects ofφ0.5mm can be detected by probes of 15 MHz and 20 MHz. The definition of defects apperance will be further improved for the probes with their frequency more than 15 MHz when the scanning step enough small. The distance of probes and defects has little effect on the detecting sensitivity.
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Subha, S., Battu Sai Krishna, Dalbir Singh, and R. Gokulnath. "Effect of Graphene Platelets/Fiber on Plastics Nanocomposites under Low-Velocity Impact Response." Applied Mechanics and Materials 852 (September 2016): 23–28. http://dx.doi.org/10.4028/www.scientific.net/amm.852.23.
Повний текст джерелаАнотація:
In this study, an attempt has made to explore the low-velocity impact response of a Carbon/epoxy laminate (CFRP) and E-Glass/epoxy laminates (GFRP). The composite was reinforced with Graphene Nanoplatelets (GnPs) and impact energy absorption capacity was studied. The plain GFRP and plain CFRP were served as a baseline for comparison. These composite laminate plates were fabricated using hand layup technique. The tests were carried out on the laminate plate as per ASTM D5628 FD. Impact tests were performed using a specially designed vertical drop-weight testing machine with an impactor mass of 1.926 kg. The result shows that laminate plate reinforced with GnPs reinforcement enhances the impact energy absorption capacity of the composites almost 4.5 % in the case Carbon/epoxy laminate and 3.5 % in the case of and E-glass/epoxy laminate. The enhanced impact resistance could be attributed to increased interlaminar fracture toughness of the fibres.