Journal articles on the topic 'CFRP'
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1
Zuo, Jian Dong, and Chao Yun Luo. "Piezoresistive Property of Carbon Fiber Reinforced Plastics." Key Engineering Materials 575-576 (September 2013): 174–78. http://dx.doi.org/10.4028/www.scientific.net/kem.575-576.174.
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Carbon fiber reinforced plastics (CFRP) were prepared by manual molding technology and the effect of loading speed on the piezoresistive property of CFPR was discussed. The piezoresistive sensitivity of CFRP with the different content of carbon fibers was contrasted and the interface morphology of CFRP was observed by SEM. The results show that CFRP has the obvious piezoresistive property and it can provide early warning as a kind of strain sensor. The piezoresistive sensitivity of CFRP decreases as the increasing of the content of carbon fibers in CFRP. Moreover the piezoresistive sensitivity of CFRP reduced as the increasing of loading speed. The SEM showed that the interface was good between carbon fibers and epoxy resin.
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Sun, Jinru, Xuanjiannan Li, Xiangyu Tian, Jingliang Chen, and Xueling Yao. "Dynamic electrical characteristics of carbon fiber-reinforced polymer composite under low intensity lightning current impulse." Advanced Composites Letters 29 (January 1, 2020): 2633366X2094277. http://dx.doi.org/10.1177/2633366x20942775.
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The distribution and conduction path of lightning current inside carbon fiber-reinforced polymer (CFRP) composites subjected to lightning strikes are determined by their dynamic conductive characteristics. An experimental platform that generates lightning current impulses with variable parameters was established to obtain the equivalent conductivities of CFRPs with different laminated structures. The experimental results indicated that the through-thickness conductivity (10−3 S/mm) was much lower than the in-plane conductivity (100 S/mm). Then, the dynamic conduction model of CFRPs was analyzed based on the anisotropic nonlinear conductivities of CFRPs under lightning currents of 50–1000 A. The CFRP laminate could be regarded as a series circuit of resistance and inductance. The dynamic conductance of the CFRP laminate first increased and then decreased during the single lightning current strike process, which was closely related to the conductive properties of the interlaminar resin. The inductive properties of the CFRP material were manifested in the test results, which showed that the voltage reached the peak value prior to the current waveform and the equivalent conductivities of the CFRPs increased as the rate of increase decreased and the duration increased. In addition, the equivalent inductance of the carbon fiber network was found to be an important part of the inductive effect of CFRP laminates. This research is helpful for understanding the complicated relationships in the lightning current conducting process and can provide experimental and theoretical support for CFRP coupled electrical–thermal simulation studies of lightning direct effects.
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Okayasu, Mitsuhiro, Yuki Tsuchiya, and Hiroaki Arai. "Experimentally and analyzed property of carbon fiber reinforced thermoplastic and thermoset plates." Journal of Materials Science Research 7, no. 3 (June 30, 2018): 12. http://dx.doi.org/10.5539/jmsr.v7n3p12.
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The tensile and fatigue properties of long unidirectional (UD) and crossply (CR) carbon fiber reinforced plastics (CFRPs) were investigated. The CFRPs in this study were fabricated from 60% CF and various resins: epoxy, polyamide (PA6), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK). The ultimate tensile strength sUTS of Epoxy-CFRP was found to be about twice that of PEEK-CFRP. Relatively high tensile strengths were found for PPS- and PA6-CFRP in the thermoset resin group, although these were still only about 85% of the strength of epoxy-CFRP. The tensile and fatigue strengths of the CR-CFRPs were less than half those of the UD-CFRPs, even though high ductilities were found for the CR-CFRPs. These high ductilities can be attributed to the crosslinking fiber effect and the low proportion of CFs in the loading direction. The sUTS values of CFRPs depend not only on the tensile strengths s and volume fractions V of CF and resin (i.e., through the conventional compound law sUTS = sfiberVfiber + sresinVresin), but also on several material properties, including the wettability of the CF by the resin. On the basis of the material properties, the ultimate tensile strengths of various UD- and CR-CFRPs were well estimated numerically through a statistical analysis, which afforded better estimates than those obtained from the compound law.
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Moon, Jae Sang, Da Young Kim, Myeong Seop Ko, and Changhyuk Kim. "Performance of Reinforced Concrete Beams Strengthened by Bidirectional Carbon-Fiber-Reinforced Polymers Based on Numerical Models." Polymers 15, no. 4 (February 17, 2023): 1012. http://dx.doi.org/10.3390/polym15041012.
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The use of carbon-fiber-reinforced polymers (CFRPs) for the repair and rehabilitation of reinforced concrete (RC) structures has been receiving a lot of attention. Specifically, the shear strengthening of RC members based on CFRP materials has been treated as an effective and efficient strengthening method. Previous research projects focused on the shear strengthening of RC members with unidirectional CFRP strips. Although the effectiveness of a bidirectional CFRP layout compared to a unidirectional CFRP layout was discussed in several studies, these studies only investigated the issue based on experiments. Morever, the parameters of the bidirectional CFRP layout were not clearly defined. This study investigates the performance of RC beams strengthened by bidirectional CFRP based on numerical models. A numerical model based on finite element analysis is designed. Using the numerical model, the parameters of the horizontal CFRP strips, such as the layouts of horizontal CFRP strips and the number of horizontal CFRP strips, are studied. The results show that the effect of horizontal CFRP strips is maximized if the strips are distributed along the depth. In contrast, the number of horizontal CFRP strips does not significantly affect the shear strength of RC members.
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Shuai, Tian, and Zhang Tong. "Study on Thermal Stress of Concrete Beams with Carbon-Fiber- Reinforced Polymers at Low Temperature." Open Construction and Building Technology Journal 8, no. 1 (December 12, 2014): 182–92. http://dx.doi.org/10.2174/1874836801408010182.
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Concrete beams reinforced with carbon-fiber-reinforced polymers (CFRPs) are subjected to considerable thermal stress at low temperatures. To mitigate this problem, this study conducts a series of tests on three concrete specimens at various temperatures, analyzes the change rule of thermal stress in CFRP-reinforced concrete beams, and discusses the influence of CFRPs on thermal stress in terms of the elastic modulus, thickness, thermal expansion coefficient, beam height, and concrete grade. The results show that when the temperature decreases, CFRP has an obvious restraining effect on the thermal curve of concrete beams. The thermal stress on the interface of CFRP-reinforced concrete beams is sufficiently large and should not be ignored. In particular, in cold areas, thermal stress should be taken into account when reinforcing structures such as concrete bridges. The CFRP sheet’s elasticity modulus and thickness are the main factors affecting the thermal stress; in comparison, the expansion coefficient and beam height have lesser effect on the thermal stress; finally, the concrete grade has little effect on the thermal stress. Thermal stress can be prevented feasibly by using prestressed CFRP sheets to reinforce concrete beams. This study can serve as a reference for concrete reinforcement design.
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Yang, Yi, Zuodong Wu, Qianziyang Zhou, Jiahao Bai, and Xinyan Guo. "An Experimental Study on Shear Performance of Adhesive Interface between Steel Plates and CFRP." Stavební obzor - Civil Engineering Journal 31, no. 4 (December 31, 2022): 561–70. http://dx.doi.org/10.14311/cej.2022.04.0042.
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CFRP (Carbon Fiber Reinforced Polymer) are widely used in steel structural reinforcement. For steel structures strengthened with CFRP, except the cases the structures have defects before strengthening, the adhesive interface is the weakest part and CFRP debonding is the most common failure mode. In order to investigate the failure mechanism of CFRP strengthened steel structures, this paper presents an experimental study on shear performance of adhesive interface between steel plate and CFRP by twin shear model. Six steel plates strengthened with CFRP are divided into two groups, one has no damage, another has a gap at the mid. The specimens are tested under tensile loadings. The study results show that, the plates with a gap failed for CFRPs debonding, the cracking loading and breaking loading are 14.85kN, and 17.88kN respectively; the strain-loading curves had long linear stages, two strains decrease and other strains of another side increased rapidly at the cracking loading, then they both rose until the plates failed.
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Yang, Yujin. "Dynamic Tensile Properties of CFRP Manufactured by PCM and WCM: Effect of Strain Rate and Configurations." Crystals 11, no. 12 (December 1, 2021): 1491. http://dx.doi.org/10.3390/cryst11121491.
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Carbon fiber-reinforced plastic (CFRP) is a promising material to achieve lightweight automotive components. The effects of the strain rate and configurations of CFRP on dynamic tensile properties have not yet been fully explored; thus, its lightweight benefits cannot be maximized. In this paper, the dynamic tensile properties of CFRPs, tested using two different processes with two different resins and four different configurations, were studied with a strain rate from 0.001 to 500 s−1. The tensile strength, modulus, failure strain, and fracture mechanism were analyzed. It was found that the dynamic performance enhances the strength and modulus, whereas it decreases the failure strain. The two processes demonstrated the same level of tensile strength but via different fracture mechanisms. Fiber orientation also significantly affects the fracture mode of CFRP. Resins and configurations both have an influence on strain rate sensitivity. An analytic model was proposed to examine the strain rate sensitivity of CFRPs with different processes and configurations. The proposed model agreed well with the experimental data, and it can be used in simulations to maximize the lightweight properties of CFRP.
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Borri, Antonio, Marco Corradi, Romina Sisti, Alessio Molinari, and Chiara Quintaliani. "Local FRP-Reinforcement of Clay Hollow Block Panels under Shear Loading." Key Engineering Materials 817 (August 2019): 450–57. http://dx.doi.org/10.4028/www.scientific.net/kem.817.450.
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The use of clay hollow blocks is common for new constructions in many parts of Europe. The results of 8 full-scale shear tests of block-masonry panels (dimensions 1.60x0.90x0.25 m) are reported in this paper. Non-defective and defective wall panels were tested in shear in the laboratory. Typical failure modes are investigated, not previously reported in the scientific literature. Test results show that the lateral load capacity of the panels is highly affected by construction defects. Furthermore, CFRPs were used in this research as local reinforcement (repair) in the area around the cracks previously opened in the masonry material. The lateral capacity for CFRP-repaired panels was restored to the original value of non-defective panels, indicating that the CFRP-repair of cracked panels is viable solution. An explanation for this phenomenon is suggested, which indicates that the high tensile strength of CFRPs can be effective in repairing cracked block-masonry. It is also argued that this large stress level of the CFRPs leads to a premature tensile CFRP crisis or a splitting failure of the blocks’ shells.
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Phan Viet, Nhut, Yukio Kitano, and Yukihiro Matsumoto. "Experimental Investigations of the Strengthening Effects of CFRP for Thin-Walled Storage Tanks under Dynamic Loads." Applied Sciences 10, no. 7 (April 6, 2020): 2521. http://dx.doi.org/10.3390/app10072521.
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In this study, the strengthening effects of different lamination conditions on carbon fiber reinforced polymers (CFRPs) for thin-walled storage tanks (TSTs) subjected to internal pressure under dynamic loads were experimentally investigated. A total of three small-scale models of TSTs were used for the investigation, including non-strengthened specimens, specimens strengthened with 0° CFRP layers, and specimens strengthened with 0°/90° CFRP layers. There were two types of tests for every specimen: the static and dynamic tests. A new experimental method using small steel balls was applied to create internal pressure in the TSTs. The results show that small steel balls could be used to increase the internal pressure compared to a normal liquid. Furthermore, the similarity rules for small-scale TSTs with small steel balls inside were also studied to consider the applicability of the models. The experimental results indicated that the CFRP layer could effectively restrain both static and dynamic hoop strains in the TSTs. Moreover, the CFRP layer could also remarkably reduce the impact of sloshing on the TST shells. The 0° CFRP layer proved to have better effects than the 0°/90° CFRP layers on the strengthening of the TSTs against dynamic loads.
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OKUYAMA, Kei-ichi, Shigeru HIBINO, and Aleksander LIDTKE. "KINETIC PROPERTY OF A PRESSURE VESSEL MADE FROM CFRP FABRICATED A FILAMENT WINDING METHOD." International Journal of Research -GRANTHAALAYAH 6, no. 3 (March 31, 2018): 140–48. http://dx.doi.org/10.29121/granthaalayah.v6.i3.2018.1507.
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Since the specific strength and the specific elasticity of carbon fiber reinforced plastics (CFRPs) are the greatest in practical materials, they are used abundantly in transport structures. This CFRP can also be used for a pressure vessel which stores liquid hydrazine, the required burst pressure is approximately 22MPa. Many researchers have been studying pressure vessels made from a CFRP fabricated by a filament winding (FW) method.
In order to acquire the fundamental mechanical properties of a CFRP container, the small cylinder made from CFRP fabricated by the spiral winding type FW method is designed and manufactured. The winding angle of a carbon fiber of this cylinder is ±45 degrees. The plastic deformation of this cylinder generates from the strain range of 0.7%. So as to confirm by the analytical method that a small tank made from CFRP fabricated by the FW method can be utilized as a tank for liquid hydrazine, an analysis model is created. Since the pressure to which the strain of this CFRP tank reaches to 0.7% is approximately 35MPa, this small tank can be used as a fuel tank for micro satellites.
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Scruggs, Alexander M., Sebastian Kirmse, and Kuang-Ting Hsiao. "Enhancement of Through-Thickness Thermal Transport in Unidirectional Carbon Fiber Reinforced Plastic Laminates due to the Synergetic Role of Carbon Nanofiber Z-Threads." Journal of Nanomaterials 2019 (January 3, 2019): 1–13. http://dx.doi.org/10.1155/2019/8928917.
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This study experimentally and analytically examined the influence of carbon nanofiber (CNF) z-threads on the through-thickness (i.e., z-direction) thermal conductivity of unidirectional carbon fiber reinforced plastics (CFRPs). It was hypothesized that a network of CNF z-threads within CFRPs would provide a thermally conductive microstructure throughout the sample thickness that would increase the through-thickness thermal conductivity. The experiments showed that the through-thickness thermal conductivity of the CNF z-threaded CFRPs (9.85 W/m-K) was approximately 7.53 times greater than that of the control CFRPs (1.31 W/m-K) and 2.73 times greater than that of the unaligned CNF-modified CFRPs (3.61 W/m-K). Accordingly, the CNF z-threads were found to play a substantial role in increasing the through-thickness thermal conductivity of CFRPs. To better understand the role of the CNF z-threads in through-thickness thermal transport, simple logical models of the CFRPs were constructed and then compared with the experimental results. Through these analyses, it was determined that CNF z-threads substantially enhance the through-thickness thermal conductivity by creating carbon fiber-CNF linkages throughout the CFRP laminate; these linkages allow the heat flow to largely bypass the resistive resin that envelops the carbon fibers. In addition, thermal infrared tests illustrated that the increased through-thickness thermal conductivity of the CNF z-threaded CFRP enabled the location and visualization of defects within the laminate, which was not possible with the control CFRP.
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Reddy, D. V., Khaled Sobhan, and Jody D. Young. "Fire Resistance of Structural Concrete Retrofitted with Carbon Fiber–Reinforced Polymer Composites." Transportation Research Record: Journal of the Transportation Research Board 2522, no. 1 (January 2015): 151–60. http://dx.doi.org/10.3141/2522-15.
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This paper presents an experimental investigation for evaluating the effects of fire exposure on properties of structural elements retrofitted by carbon fiber–reinforced polymers (CFRPs). Mechanical properties of CFRP-strengthened reinforced concrete (RC) members, protected with secondary insulation, were investigated, before and after (residual) direct fire exposure. Direct fire contact resulted in a reduction in capacity of 9% to 20% for CFRP-strengthened RC beams and 15% to 34% for CFRP-strengthened RC columns. Furthermore, a similitude analysis was developed for a heat transfer relationship between full-scale and small-scale specimens, allowing a one-fourth exposure time reduction for the latter. Results from the experimental investigations demonstrated the benefits of employing secondary fire protection to CFRP-strengthened structures, despite the glass transition temperature being exceeded in the early stages of the elevated-temperature exposure. Therefore, it is suggested that fire protection is necessary for a CFRP-strengthened structure to retain integrity throughout the duration of the fire exposure and on return to ambient temperature. The conclusions of this investigation will lead to recommendations and guidelines to designers and practicing engineers for using CFRP materials in retrofitting RC structures with adequate fire resistance by contributing to the missing information for fire protection requirements not available in codes of practice.
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Guo, Yu Qin, Zhao Meng, Fu Zhu Li, Wei Chen, and Juan Guo. "An Integrated Manufacturing Process of CFRP Parts Based on RFI and Cutting Process." Applied Mechanics and Materials 365-366 (August 2013): 1090–94. http://dx.doi.org/10.4028/www.scientific.net/amm.365-366.1090.
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Due to the prominent mechanical and physical properties, CFRPs have a broad application prospects in many domains. Aiming to the problems faced by available machining processes of CFRPs, this work proposed an integrated manufacturing process of CFRP parts by combining RFI process with cutting process, which replaced machining processes of the difficult-to-machine CFRPs with cutting of the flexible carbon fiber fabrics infiltrated by melted resin matrix. And it carried out molding, cutting and curing in a press stroke by a multi-functional die whose structure is given in this paper. Furthermore, by comparing the cross-section quality of CFRP parts obtained from the proposed integrated manufacturing process with that of drilling, mechanical machining and laser cutting, the integrated manufacturing process is verified to be feasible, cost-effective and capable of avoiding subsequent machining processes of difficult-to-machine CFRPs.
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Attahu, C. Y., J. Yang, KH Wong, and C. K. Thein. "Flexural and shear strength properties of unidirectional carbon fiber reinforced polymer composite interleaved with recycled carbon fiber and short virgin aramid fiber non-woven mats." IOP Conference Series: Materials Science and Engineering 1225, no. 1 (February 1, 2022): 012005. http://dx.doi.org/10.1088/1757-899x/1225/1/012005.
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Abstract Carbon fiber reinforced polymer composites (CFRPs) are one of the most widely used composite types and wastes associated with them (CFRPs) get generated through either their manufacturing or end-of-service-life. Predominately due to environmental concerns and governmental regulations, recycling these CFRPs is needed and to make use of the recycled carbon fibers (rCFs), a wet paper-making technique was used to convert the rCFs into a 60 g/m2non-woven mat. For comparison purposes, the same technique was used to convert short virgin aramid fibers (vAFs) into a 60 g/m 2 non-woven mat. Each mat was sandwiched with two resin films and then interleaved with 12-ply unidirectional (UD) prepreg tapes (carbon/epoxy). The assemblage was molded into composite laminates using a vacuum bagging assisted compression molding technique, and the samples for the tests were cut using a waterjet machine accordingly. Compared with the control, the results indicate an increment in the flexural modulus, and the specific flexural modulus for the CFRPs with non-woven mats: the flexural modulus increased by approximately 8.2% and 12.0% for the CFRP with rCF and vAF mats, respectively; the specific flexural modulus increased around 9.5% and 13.3%, respectively for the CFRP with rCF and vAF mats. On the other hand, the shear strength approximately decreased by 6.4% and 6.0% for the CFRP with rCF and vAF mats, respectively. The negative shear strength performances of the composite laminates with non-woven mats reflected on their flexural strength performances: the flexural strength increased about 1.1% and decreased by approximately 7.9% for the CFRP with vAF and rCF mats, respectively. To resolve the negative shear strength performances, it is recommended that the surfaces of the mats be treated with a coupling agent to improve their interfacial adhesions.
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Song, Peng, Junyan Liu, Zhijie Li, Siyuan Wu, Xiaogang Sun, Honghao Yue, and Michal Pawlak. "All-optical laser ultrasonic technique for imaging of subsurface defects in carbon fiber reinforced polymer (CFRP) using an optical microphone." Journal of Applied Physics 131, no. 16 (April 28, 2022): 165106. http://dx.doi.org/10.1063/5.0087304.
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Defects, such as delamination and debonding, are critical to the performance of carbon fiber-reinforced polymer (CFRP) composites. In recent years, non-destructive testing techniques have been improved for the inspection of these defects among CFRPs. In this study, an all-optical and non-destructive laser ultrasonic technique with an optical microphone detection module has been presented to detect the artificial subsurface defects among the CFRP composites. A finite element simulation based on the thermo-mechanical coupling model was used to study the process of nanosecond pulsed laser excitation of the CFRP laminate to produce ultrasound and the propagation behavior of ultrasound among the CFRP laminate. A series of non-contact laser ultrasonic testing experiments were carried out to study the flat bottom holes of different sizes via a laser ultrasonic detection system. The artificial subsurface defects were reliably identified by the presented all-optical laser ultrasonic system imbedded in the optical microphone using four feature images.
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Ma, Ying, Denzel Bridges, Yongchao Yu, Jitai Han, Hong Li, and Anming Hu. "Joining of Carbon Fiber Reinforced Plastic to Aluminum Alloy by Reactive Multilayer Films and Low Power Semiconductor Laser Heating." Applied Sciences 9, no. 2 (January 17, 2019): 319. http://dx.doi.org/10.3390/app9020319.
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This study investigated the characteristics and strength of the dissimilar joints between carbon fiber reinforced plastic (CFRP) epoxy composites and aluminum alloys using two different heating methods, Ni/Al reactive multilayer films (RMF) and a low power continuous wave diode laser. To enhance the adhesion, the top resin layer of the CFRP and the surface of the aluminum alloy were patterned by femtosecond laser. Polycarbonate (PC) was used as a filler material during the joining processes. ANSYS simulation was applied to elucidate the thermal kinetics of the self-propagation reaction and the thermal profile, and evaluate the possibility of joining CFRP to aluminum using Ni/Al RMFs. The SEM image of the cross-section shows that melted PC flowed into the CFRP–aluminum alloy interface, suggesting strong mechanical bonding. A tensile strength of 9.5 MPa was reached using Ni/Al multilayers as heat sources, which provides a new way for joining CFRPs and aluminum alloys in space or under water.
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Shin, Yong-Chul, and Seung-Mo Kim. "Enhancement of the Interlaminar Fracture Toughness of a Carbon-Fiber-Reinforced Polymer Using Interleaved Carbon Nanotube Buckypaper." Applied Sciences 11, no. 15 (July 24, 2021): 6821. http://dx.doi.org/10.3390/app11156821.
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In this study, a carbon nanotube (CNT) buckypaper was interleaved in a carbon-fiber-reinforced polymer (CFRP) composite to improve the interlaminar fracture toughness. Interleaving the film of a laminate-type composite poses the risk of deteriorating the in-plane mechanical properties. Therefore, the in-plane shear modulus and shear strength were measured prior to estimating the interlaminar fracture toughness. To evaluate the effect of the buckypaper on the interlaminar fracture toughness of the CFRP, double cantilever beam (DCB) and end notch flexure (ENF) tests were conducted for mode I and mode II delamination, respectively. No significant change was observed for the in-plane shear modulus due to the buckypaper interleaving and the shear strength decreased by 4%. However, the interlaminar fracture toughness of the CFRP increased significantly. Moreover, the mode II interlaminar fracture toughness of the CFRP increased by 45.9%. Optical micrographs of the cross-section of the CFRPs were obtained to compare the microstructures of the specimens with and without buckypaper interleaving. The fracture surfaces obtained after the DCB and ENF tests were examined using a scanning electron microscope to identify the toughening mechanism of the buckypaper-interleaved CFRP.
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Tamura, Shoichi, and Takashi Matsumura. "Cutting Force Model in Milling of Carbon Fiber Reinforced Plastic." Key Engineering Materials 611-612 (May 2014): 1166–73. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.1166.
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The demand of carbon fiber reinforced plastics (CFRP) has been increased in aircraft and automobile industries. In milling of CFRP, the cutting parameters should be determined to finish the machining surfaces without delamination. The tool wear is also a critical issue to finish good surfaces. The paper presents a force model to study the milling process of CFRP. In order to investigate the anisotropy in milling of CFRP, the cutting tests were conducted for unidirectional CFRPs with changing the feed direction of the milling tool. The cutting force and the surface finish depend on the feed direction with respect to the fiber orientation. A force model based on the minimum cutting energy is applied to milling of CFRP. The orthogonal cutting data used in the force model is associated with the relative angle of the cutting edge rotation angle to the fiber orientation. The model was verified in comparison between the predicted and the measured cutting forces. The model also estimates the effect of the feed direction with respect to the fiber orientations on the cutting force in terms of anisotropy in the orthogonal cutting data.
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Stamopoulos, Antonios, Konstantinos Tserpes, and Argyris Dentsoras. "Prediction of mechanical properties of porous CFRP specimens by ANNs and X-ray CT data." MATEC Web of Conferences 188 (2018): 01002. http://dx.doi.org/10.1051/matecconf/201818801002.
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Carbon fiber reinforced plastics (CFRPs) have evolved into the primary material for several lightweight structures. However, despite their extensive use and the quality amelioration, CFRPs remain susceptible to a variety of manufacturing defects, the most common of which are the pores. Predictive tools capable of correlating the mechanical properties of CFRP parts with the characteristics of defects as derived from non-destructive testing (NDT) techniques or even further with the manufacturing parameters could serve as an effective tool for the quality control of CFRP structural parts. In the present paper, the characteristics of pores as evaluated by X-ray Computed Tomography (CT) have been correlated with the matrixdominated mechanical properties of unidirectional porous CFRP specimens using Artificial Neural Networks (ANN). Thirty (30) porosity scenarios have been created and given as input to the numerical model. That multi-scale numerical model, which had been validated experimentally, has been used for training the ANN model. The predictions of the ANN agree very well with results from mechanical tests. Moving one step forward, a second ANN has been developed to correlate the autoclave pressure directly with the mechanical properties of the CFRP specimens. The validity of the latter ANN depends on the accuracy of the relation between the autoclave pressure and the characteristics of the pores. The present work represents a step towards the development of effective quality control tools for composite materials.
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Zhu, Yansong, Yueke Ming, Ben Wang, Yugang Duan, Hong Xiao, Chenping Zhang, Jinru Sun, and Xiangyu Tian. "Finite Element Analysis of Lightning Damage Factors Based on Carbon Fiber Reinforced Polymer." Materials 14, no. 18 (September 10, 2021): 5210. http://dx.doi.org/10.3390/ma14185210.
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While carbon-fiber-reinforced polymers (CFRPs) are widely used in the aerospace industry, they are not able to disperse current from lightning strikes because their conductivity is relatively low compared to metallic materials. As such, the undispersed current can cause the vaporization or delamination of the composites, threatening aircraft safety. In this paper, finite element models of lightning damage to CFRPs were established using commercial finite element analysis software, Abaqus, with the user-defined subroutines USDFLD and HEAVEL. The influences of factors such as the structural geometry, laminate sequence, and intrinsic properties of CFRPs on the degree of damage to the composites are further discussed. The results showed that when a current from lightning is applied to the CFRP surface, it mainly disperses along the fiber direction in the outermost layer. As the length of the CFRP increases, the injected current has a longer residence time in the material due to the increased current exporting distance. Consequently, larger amounts of current accumulate on the surface, eventually leading to more severe damage to the CFRP. This damage can be alleviated by increasing the thickness of the CFRP, as the greater overall resistance makes the CFRP a better insulator against the imposed current. This study also found that the damaged area increased as the angle between the first two layers increased, whereas the depth of the damage decreased due to the current dispersion between the first two layers. The analysis of the electrical conductivity of the composite suggested that damage in the fiber direction will be markedly reduced if the conductivity in the vertical fiber direction increases approximately up to the conductivity of the fiber direction. Moreover, increasing the thermal conductivity along the fiber direction will accelerate the heat dissipation process after the lightning strike, but the influence of the improved thermal conductivity on the extent of the lightning damage is less significant than that of the electrical conductivity.
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NAKATA, Kazuhiro. "Joining of CFRP/CFRTP and Multi-Material." Journal of the Society of Materials Science, Japan 69, no. 6 (June 15, 2020): 479–84. http://dx.doi.org/10.2472/jsms.69.479.
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HOSOI, Atsushi. "Joining of CFRP/CFRTP and Multi-Material." Journal of the Society of Materials Science, Japan 69, no. 7 (July 15, 2020): 563–67. http://dx.doi.org/10.2472/jsms.69.563.
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Sato, Chiaki. "Joining of CFRP/CFRTP and Multi-Material." Journal of the Society of Materials Science, Japan 69, no. 8 (August 15, 2020): 626–29. http://dx.doi.org/10.2472/jsms.69.626.
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Liu, Shukui, Wei Sun, Hongwen Jing, and Zhaoxing Dong. "Debonding Detection and Monitoring for CFRP Reinforced Concrete Beams Using Pizeoceramic Sensors." Materials 12, no. 13 (July 4, 2019): 2150. http://dx.doi.org/10.3390/ma12132150.
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The bonding status between Carbon Fiber Reinforced Polymer (CFRP) and concrete is one of the key issues for the safety of CFPR-reinforced structures, thus it is of great importance to detect the debonding as early as possible. Instead of detecting the debonding which is artificially set at the very beginning, this paper investigates the feasibility of using low-cost piezoceramic sensors to detect and monitor the debonding of CFRP-reinforced concrete beams in situ. For existing debonding detection, a concrete beam reinforced with CFRP sheet was loaded through the three-point bending test till failure to induce debonding between CFRP sheet and the concrete substrate, and piezoceramic sensors were used to detect the existing debonding by analyzing the receiving ultrasonic waves. In addition, the debonding detection results were further compared with and verified by the vision-based strain testing results. For in-situ debonding monitoring, 10 piezoceramic sensors were used as an array to track the wave transmission changes during the loading process of a CFRP-reinforced concrete beam, and the debonding development process was successfully monitored. The test results show that the low-cost piezoceramic sensors are very effective to generate and receive ultrasonic waves, and are capable of detecting the existing debonding and monitoring of the in-situ debonding process as well.
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Li, Wuzhou, Liangang Zheng, Yang Gao, Yuzhe Xie, and Fujun Xu. "Interfacial Bonding Enhancement Between Cryogenic Conditioned Carbon Fiber and Epoxy Resin Characterized by the Single-Fiber Fragmentation Method." AATCC Journal of Research 8, no. 4 (July 1, 2021): 1–7. http://dx.doi.org/10.14504/ajr.8.4.1.
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Carbon fiber (CF) is an important structural material due to its favorable mechanical and physical properties. However, poor interfacial bonding with polymer resin severely affects the mechanical performance of carbon fiber reinforced polymer composites (CFRP). In this study, the single-fiber CFRPs were treated using multi-stage cryogenic approaches to optimize the interfacial shear strength (IFSS) between carbon fiber and epoxy resin. The carbon fiber was pretreated by cryogenic treatment with sharp and slow cooling rates, followed by the same treatment of the single-fiber CFRP composed of the pretreated carbon fiber to reach the optimal interfacial modification. The IFSS value was increased by 27.4% when the carbon fiber was pretreated at a slow cooling rate, and its single-fiber CFRP was treated at a sharp cooling rate.
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Wang, Zhenyu, Yang Zhao, Xu Liang, and Zhiguo He. "Analysis of the Dynamic Response in Blast-Loaded CFRP-Strengthened Metallic Beams." Advances in Materials Science and Engineering 2013 (2013): 1–13. http://dx.doi.org/10.1155/2013/521404.
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Carbon fiber-reinforced polymer composites (CFRPs) are good candidates in enhancing the blast resistant performance of vulnerable public buildings and in reinforcing old buildings. The use of CFRP in retrofitting and strengthening applications is traditionally associated with concrete structures. Nevertheless, more recently, there has been a remarkable aspiration in strengthening metallic structures and components using CFRP. This paper presents a relatively simple analytical solution for the deformation and ultimate strength calculation of hybrid metal-CFRP beams when subjected to pulse loading, with a particular focus on blast loading. The analytical model is based on a full interaction between the metal and the FRP and is capable of producing reasonable results in a dynamic loading scenario. A nonlinear finite element (FE) model is also developed to reveal the full dynamic behavior of the CFRP-epoxy-steel hybrid beam, considering the detailed effects, that is, large strains, high strain rates in metal, and different failure modes of the hybrid beam. Experimental results confirm the analytical and the FE results and show a strong correlation.
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Bliznakova, Kristina, Zacharias Kamarianakis, Aris Dermitzakis, Zhivko Bliznakov, Ivan Buliev, and Nicolas Pallikarakis. "Modelling of small CFRP aerostructure parts for X-ray imaging simulation." International Journal of Structural Integrity 5, no. 3 (August 12, 2014): 227–40. http://dx.doi.org/10.1108/ijsi-02-2014-0009.
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Purpose – The purpose of this paper is to develop a realistic computational model of carbon fibre reinforced polymer (CFRP) structures dedicated for in-silico investigations of the use of X-ray-based imaging techniques as non-destructive testing (NDT) of CFRP parts. Design/methodology/approach – CFRPs contain layers of carbon-fibres bundles within resin. Bundles’ orientation in the different layers is arranged with respect to each other at a well-defined primary direction. In the model, the bundle was simulated as a circular cylinder. The resulted model is a stack of layers of unidirectional bundles having orientation of 0°/90°/45°/−45°. Two CFRP structures were modelled: a flat CFRP part and a real shaped CFRP clip. A porous layer and non-carbon fibres were inserted within each model, respectively. X-ray projection images were generated with a dedicated simulation programme. Three setups were investigated: radiography, tomosynthesis and cone-beam CT (CBCT). Findings – Results showed that porosity and non-carbon fibres were visible with all X-ray-based techniques. Tomosynthesis and CBCT, however, provide higher quality image of defects. Practical implications – The CFRP computational model is a valuable tool in design, testing and optimization phase of X-ray-based imaging techniques for use in NDT of composite materials. Simulated images are generated within a short time; thus results from virtual optimization and testing are obtained very fast and at low cost. Originality/value – An innovative computational model of CFRP structures, dedicated for X-ray imaging simulations, has been developed. The model is characterized by simplicity in its creation and realistic visual appearance of the produced X-ray images.
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Ozkan, Dervis, Peter Panjan, Mustafa Sabri Gok, and Abdullah Cahit Karaoglanli. "Experimental Study on Tool Wear and Delamination in Milling CFRPs with TiAlN- and TiN-Coated Tools." Coatings 10, no. 7 (June 29, 2020): 623. http://dx.doi.org/10.3390/coatings10070623.
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Carbon fiber-reinforced polymers (CFRPs) have very good mechanical properties, such as extremely high tensile strength/weight ratios, tensile modulus/weight ratios, and high strengths. CFRP composites need to be machined with a suitable cutting tool; otherwise, the machining quality may be reduced, and failures often occur. However, as a result of the high hardness and low thermal conductivity of CFRPs, the cutting tools used in the milling process of these materials complete their lifetime in a short cycle, due to especially abrasive wear and related failure mechanisms. As a result of tool wear, some problems, such as delamination, fiber breakage, uncut fiber and thermal damage, emerge in CFRP composite under working conditions. As one of the main failure mechanisms emerging in the milling of CFRPs, delamination is primarily affected by the cutting tool material and geometry, machining parameters, and the dynamic loads arising during the machining process. Dynamic loads can lead to the breakage and/or wear of cutting tools in the milling of difficult-to-machine CFRPs. The present research was carried out to understand the influence of different machining parameters on tool abrasion, and the work piece damage mechanisms during CFRP milling are experimentally investigated. For this purpose, cutting tests were carried out using a (Physical Vapor Deposition) PVD-coated single layer TiAlN and TiN carbide tool, and the abrasion behavior of the coated tool was investigated under dry machining. To understand the wear process, scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS) was used. As a result of the experiments, it was determined that the hard and abrasive structure of the carbon fibers caused flank wear on TiAlN- and TiN-coated cutting tools. The best machining parameters in terms of the delamination damage of the CFRP composite were obtained at high cutting speeds and low feed rates. It was found that the higher wear values were observed at the TiAlN-coated tool, at the feed rate of 0.05 mm/tooth.
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Nie, Hong-bin, and Shuan-cheng Gu. "Ultimate Bearing Capacity Analysis of CFRP-Strengthened Shield Segments Using Bonding Slip Behavior Experiments." Materials 13, no. 18 (September 21, 2020): 4200. http://dx.doi.org/10.3390/ma13184200.
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Shield segments of subway tunnels are often exposed to the combined actions of several hygrothermal factors that could lead to accidents such as water seepage and tunnel collapse. Further, they often break and deform owing to formation pressure. In addition, uncertainties related to the stress relaxation characteristics and bonding performance of carbon-fiber-reinforced plastics (CFRPs) under a hygrothermal environment make their application in subway systems difficult. This study analyzes the effects of the slip-on-bending strength of CFRP-strengthened shield segments in a hygrothermal environment. In the study, the shield segments are damaged at ambient pressure under a combination of humidity (0%, 5%, and 10%) and temperature (20 °C, 25 °C, 30 °C, and 40 °C). An experimental procedure is designed to evaluate a CFRP-reinforced concrete arch. The method predicts the load–slip relationship and maximum shearing stress and strain. Moreover, confined compression tests are conducted on a tunnel segment lining strengthened with CFRP to evaluate the bearing capacity of the CFRP-strengthened shield segments. An equation for the latter’s ultimate bearing capacity is developed based on the elastic layer system theory, stress boundary condition, and bending stress characteristics of axisymmetric elements. It was found that the results from the developed model are compared with the experimental values of CFRP-strengthened shield segments under different humidity values (0%, 5%, and 10%) and a constant temperature. The ultimate strength—the debonding deflection of the CFRP-strengthened shield segment—can be predicted using the proposed ultimate bearing capacity equation with sufficient accuracy.
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Maccaferri, Emanuele, Laura Mazzocchetti, Tiziana Benelli, Tommaso Maria Brugo, Andrea Zucchelli, and Loris Giorgini. "Rubbery-Modified CFRPs with Improved Mode I Fracture Toughness: Effect of Nanofibrous Mat Grammage and Positioning on Tanδ Behaviour." Polymers 13, no. 12 (June 9, 2021): 1918. http://dx.doi.org/10.3390/polym13121918.
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Carbon Fiber Reinforced Polymers (CFRPs) are widely used where high mechanical performance and lightweight are required. However, they suffer from delamination and low damping, severely affecting laminate reliability during the service life of components. CFRP laminates modified by rubbery nanofibers interleaving is a recently introduced way to increase material damping and to improve delamination resistance. In this work, nitrile butadiene rubber/poly(ε-caprolactone) (NBR/PCL) blend rubbery nanofibrous mats with 60 wt% NBR were produced in three different mat grammages (5, 10 and 20 g/m2) via single-needle electrospinning and integrated into epoxy CFRP laminates. The investigation demonstrated that both mat grammage and positioning affect CFRP tanδ behaviour, evaluated by dynamic mechanical analysis (DMA) tests, as well as the number of nano-modified interleaves. Double cantilever beam (DCB) tests were carried out to assess the mat grammage effect on the interlaminar fracture toughness. Results show an outstanding improvement of GI,R for all the tested reinforced laminates regardless of the mat grammage (from +140% to +238%), while the effect on GI,C is more dependent on it (up to +140%). The obtained results disclose the great capability of NBR/PCL rubbery nanofibrous mats at improving CFRP damping and interlaminar fracture toughness. Moreover, CFRP damping can be tailored by choosing the number and positioning of the nano-modified interleaves, besides choosing the mat grammage.
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Czypionka, Stefan, and Frank Kienhöfer. "Weight reduction of a carbon fibre composite wheel." Science and Engineering of Composite Materials 26, no. 1 (January 28, 2019): 338–46. http://dx.doi.org/10.1515/secm-2019-0018.
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AbstractThe wheel of a passenger vehicle must be designed to be safe and light. Despite the tremendous potential of carbon fibre as an automotive material due to high strength and low weight, the prevalence of carbon fibre reinforced plastics (CFRPs) in vehicle wheels is limited. Manufacturing and testing CFRP prototypes is expensive. Thus it is advantageous to develop simulation models for composite weight reduction. The simulation models can provide insight into how lighter CFRP wheels can be designed. This study presents the design development of a CFRP wheel for a high-performance roadster; the CFRP wheel is offered by an automotive manufacturer as a high-performance option instead of aluminium wheels. Finite element (FE) simulations were initially conducted assuming an isotropic material. This initial model was used to eliminate stress concentrations and to design and manufacture an initial CFRP wheel. The CFRP wheel weight is 6.8 kg as compared to the original aluminium wheel which weighs 8.1 kg. This initial design passed the dynamic cornering fatigue test (the most stringent strength test for wheels). Thereafter the wheel was instrumented with strain gauges and a bending moment was applied to the hub using a custom-built test rig. The test rig produced a static load equivalent to the dynamic cornering fatigue test (in which the applied bending moment varies sinusoidally). The test rig allowed for the deflection of the load arm to be measured. The comparison of the experimentally measured strains and an FE model which includes the CFRP laminate properties showed good agreement. Two alternative laminate options were simulated using the FE model. These showed both an increase in stiffness and a calculated weight reduction. This study shows that an aluminium wheel for a high-performance roadster can be redesigned using CFRP to be 16% lighter and using a FE model a further 152 g weight reduction is possible (18% weight reduction in total when compared to the aluminium wheel).
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Oh, Hyun-Taik, Jong-Ick Won, Sung-Choong Woo, and Tae-Won Kim. "Determination of Impact Damage in CFRP via PVDF Signal Analysis with Support Vector Machine." Materials 13, no. 22 (November 18, 2020): 5207. http://dx.doi.org/10.3390/ma13225207.
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Carbon fiber reinforced plastics (CFRPs) have high specific stiffness and strength, but they are vulnerable to transverse loading, especially low-velocity impact loadings. The impact damage may cause serious strength reduction in CFRP structure, but the damage in a CFRP is mainly internal and microscopic, that it is barely visible. Therefore, this study proposes a method of determining impact damage in CFRP via poly(vinylidene fluoride) (PVDF) sensor, which is convenient and has high mechanical and electrical performance. In total, 114 drop impact tests were performed to investigate on impact responses and PVDF signals due to impacts. The test results were analyzed to determine the damage of specimens and signal features, which are relevant to failure mechanisms were extracted from PVDF signals by means of discrete wavelet transform (DWT). Support vector machine (SVM) was used for optimal classification of damage state, and the model using radial basis function (RBF) kernel showed the best performance. The model was validated through a 4-fold cross-validation, and the accuracy was reported to be 92.30%. In conclusion, impact damage in CFRP structures can be effectively determined using the spectral analysis and the machine learning-based classification on PVDF signals.
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Che, Han Qing, André Liberati, Phuong Vo, and Stephen Yue. "Cold Spray of Mixed Sn-Zn and Sn-Al Powders on Carbon Fiber Reinforced Polymers." Materials Science Forum 941 (December 2018): 1892–97. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1892.
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Carbon fiber reinforced polymers (CFRPs) have been increasingly used in the latest generations of aircraft and helicopters for lightweight purposes, but this leaves vulnerability against lightning strike. Cold spray is one coating approach to metallize the polymers, thus making them lightning strike proof. It has been reported that direct cold spray of metals onto CFRP is difficult. However, research at McGill University has shown that tin coatings can be cold sprayed on CFRP, but the deposition efficiency is very low. In this work, aluminum and zinc powders were mixed with tin to investigate the effect of mixing on deposition efficiency of the coating. The mixed metal powders were cold sprayed on CFRP with a low-pressure cold spray system at various conditions. It was found that the addition of aluminum or zinc resulted led to increased deposition efficiencies compared to pure tin, but there are many differences in the details of the effect of Al and Zn additions on the deposition characteristics. The deposition mechanism of the mixed metal powders on CFRP is discussed, and the effect of mixing powders on the deposition efficiency is evaluated.
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Yamashita, Shinnosuke, Tatsuya Furuki, Hiroyuki Kousaka, Toshiki Hirogaki, Eiichi Aoyama, Kiyofumi Inaba, and Kazuna Fujiwara. "Investigation of Optimum Grinding Condition Using cBN Electroplated End-Mill for CFRP Machining." International Journal of Automation Technology 15, no. 1 (January 5, 2021): 4–16. http://dx.doi.org/10.20965/ijat.2021.p0004.
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Recently, carbon fiber reinforced plastics (CFRP) have been used in various applications such as airplanes and automobiles. In CFRP molding, there are unnecessary portions on the outer area. Therefore, a machining process is required to remove them. Cutting and grinding are conventionally used in the finish machining of CFRPs. End-milling allows the removal of most of these portions. However, uncut fibers easily occur during end-milling. In contrast, a precise machined surface and edge are easily obtained using a grinding tool. Therefore, this research has developed a novel cubic boron nitride (cBN) electroplated end-mill that combines an end-mill and a grinding tool. This is a versatile tool that can cut and grind CFRPs by changing the direction of rotation of the tool. In this study, the effectiveness of the developed tool is investigated. First, the developed tool machined the CFRP by side milling. Consequently, cBN abrasives that were fixed on the outer surface of the developed tool did not detach in certain cutting conditions. Next, in order to generate a sharp edge on the CFRP and restrict the increase in the CFRP temperature with the cBN electroplated end-mill, the optimum abrasive size and grinding condition were investigated through the design of experiments. Moreover, the effectiveness of the developed tool was verified by comparing it with a conventional tool. As a result, smaller burrs and uncut fibers were observed after final machining with the developed tool under the derived optimum condition than those with conventional tools. However, the desired surface roughness could not be achieved as required by the airline industry. Therefore, oscillating grinding was applied. In addition, the formula of the theoretical surface roughness while using the developed tool was derived using the theory of slant grinding. As a result, the oscillating condition that led to the required surface roughness was obtained by theoretical analysis. In addition, the required value for the airline industry was achieved by oscillating grinding.
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Okada, Takumi, J. H. Quan, Naoya Tsuchikura, Tatsuya Yamamoto, Masae Kanda, Michael C. Faudree, and Yoshitake Nishi. "Cost Cut with High Impact Value of Sandwich Structure with Inexpensive ABS Core between High Strength CFRP Laminate Plies." Advanced Materials Research 922 (May 2014): 563–67. http://dx.doi.org/10.4028/www.scientific.net/amr.922.563.
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Sandwich structural composites (CFRP/ABS/CFRP) of inexpensive acrylonitrile butadiene styrene (ABS) cores (2.0 mm thickness) between carbon fiber reinforced epoxy (CFRP) laminate plies (2.5 mm thickness) were suggested and prepared, since the materials cost of ABS resin was about 8% that of CFRP. Although Young’s modulus of CFRP/ABS/ CFRP is slightly smaller than that of CFRP, Charpy impact value (auc) of the CFRP/ABS/CFRP approximately corresponded to that of CFRP composite. Furthermore, applying homogeneous low voltage electron beam irradiation (HLEBI) to both side surfaces improved theaucof CFRP/ABS/CFRP. Since the irradiated depth estimated is about 119 ± 23 μm, the irradiation effects mostly acted within the CFRP sheet. The Charpy impact value (auc) of CFRP/ABS/CFRP at mid-fracture probability (Pf) after irradiation at 0.30 MGy (kJg_1) was approximately 25 % higher than that before treatment. It was approximately equal to that for irradiated CFRP and was also about 20% higher than that of the CFRP before treatment. Although the use of ABS resin as the core reduced other mechanical properties of tensile and bending, the materials cost of CFRP/ABS/CFRP was approximately 25 % that of CFRP. Thus, the sandwich structural composites of CFRP/ABS/CFRP could be utilized for daily articles.
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Ofoegbu, Stanley, Mário Ferreira, and Mikhail Zheludkevich. "Galvanically Stimulated Degradation of Carbon-Fiber Reinforced Polymer Composites: A Critical Review." Materials 12, no. 4 (February 21, 2019): 651. http://dx.doi.org/10.3390/ma12040651.
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Carbon is used as a reinforcing phase in carbon-fiber reinforced polymer composites employed in aeronautical and other technological applications. Under polarization in aqueous media, which can occur on galvanic coupling of carbon-fiber reinforced polymers (CFRP) with metals in multi-material structures, degradation of the composite occurs. These degradative processes are intimately linked with the electrically conductive nature and surface chemistry of carbon. This review highlights the potential corrosion challenges in multi-material combinations containing carbon-fiber reinforced polymers, the surface chemistry of carbon, its plausible effects on the electrochemical activity of carbon, and consequently the degradation processes on carbon-fiber reinforced polymers. The implications of the emerging use of conductive nano-fillers (carbon nanotubes and carbon nanofibers) in the modification of CFRPs on galvanically stimulated degradation of CFRP is accentuated. The problem of galvanic coupling of CFRP with selected metals is set into perspective, and insights on potential methods for mitigation and monitoring the degradative processes in these composites are highlighted.
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Corradi, Marco, Giulio Castori, Romina Sisti, Antonio Borri, and Giovanni Luca Pesce. "Repair of Block Masonry Panels with CFRP Sheets." Materials 12, no. 15 (July 25, 2019): 2363. http://dx.doi.org/10.3390/ma12152363.
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In the 1980s, block masonry started to be widely used for new constructions in Italy’s earthquake prone areas. However, recent seismic events demonstrated that block masonry buildings may need to be repaired after earthquakes due to cracking. Construction defects are the main cause for cracking of block work masonry. Carbon fiber reinforced polymer (CFRP) sheets have been used as a local repair method for non-defective and defective wall panels. An experimental program was formulated to investigate the shear behavior of block masonry walls repaired with CFRP sheets. A total of six wall panels were constructed in the laboratory and tested in shear (in-plane lateral loading). It was found that, although the control (non-defective) wall panels had a high ultimate load capacity, the use of CFRPs reduces the effects of construction defects and restores the lateral load capacity in non-defective walls. Overall, this research suggests that the use of epoxy-bonded CFRP sheets could be used for local repair of cracked wall panels.
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Ahmad Sobri, Sharizal, Robert Heinemann, and David Whitehead. "Development of Laser Drilling Strategy for Thick Carbon Fibre Reinforced Polymer Composites (CFRP)." Polymers 12, no. 11 (November 12, 2020): 2674. http://dx.doi.org/10.3390/polym12112674.
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Composites from carbon fibre reinforced polymers (CFRPs) play a significant role in modern manufacturing. They are typically used in aerospace and other industries that require high strength-to-weight ratios. Composite machining, however, remains a challenging job and sometimes is hampered by poor efficiency. Despite considerable research being conducted over the past few years on the machining of composite materials, the material nevertheless suffers from delamination, fibre loss, and imperfect finishing of the fuselage. Laser technology is becoming increasingly popular as an alternative approach to cutting and drilling composites. Experiments have been conducted with a CFRP thickness of 25.4 mm using fibre laser to test the effect of the machining parameters on the primary performance measurements. In this study, different machining criteria are used to assess the fibre laser ability of thick CFRP composites for drilling operation. The experimental findings revealed that a fibre laser is capable of penetrating a thick CFRP to a depth of 22 mm by using a novel drilling procedure.
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Akai, Kenju, Yuji Kageyama, Kaoru Sato, Nariaki Nishino, and Kazuro Kageyama. "AHP Analysis of the Preference of Engineers for Suitable CFRP for Automobile Parts." International Journal of Automation Technology 9, no. 3 (May 5, 2015): 222–34. http://dx.doi.org/10.20965/ijat.2015.p0222.
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A questionnaire survey was conducted and analyzed with the analytic hierarchy process (AHP) to evaluate the suitability of carbon-fiber-reinforced plastic (CFRP) for use in automobile parts from an engineer’s viewpoint. The results indicated that carbon fiber has a higher potential for use in the framework than as an outer panel or exterior material. In addition, unidirectional and isotropic CFRPs can be used as alternatives to steel for higher-class automobiles. The critical evaluation criteria for carbon fiber are the material cost, safety, stiffness, and corrosion resistance. With the innovative carbon fiber project of the Ministry of Economy, Trade and Industry, CFRP has high potential as an alternative material for not only Class S but also Class A automobiles. In a dramatic innovation scenario with regard to the safety, stiffness, and thermal degradation of carbon fiber, CFRP was found to be a potential alternative material for more than half of the parts of Class A automobiles and several parts of Class C automobiles.
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Geier, Norbert. "Influence of fibre orientation on cutting force in up and down milling of UD-CFRP composites." International Journal of Advanced Manufacturing Technology 111, no. 3-4 (October 6, 2020): 881–93. http://dx.doi.org/10.1007/s00170-020-06163-3.
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Abstract Machining of carbon fibre reinforced polymer (CFRP) composites is extremely difficult, mainly due to their inhomogeneous and anisotropic properties. Predicting of cutting force during machining of CFRP is also difficult because the machinability properties of the composite are significantly orientation-dependent (fibre and machining directions). The main objective of the present study is to analyse the influence of fibre orientation on cutting force in milling of unidirectional CFRP. Up and down milling experiences were conducted based on a full factorial design. Experimental data were processed by fast Fourier transformation, regression analysis, and graphical adequate analysis. Multiple-order polynomial models were developed in order to minimise cutting force. Experimental results show that fibre orientation angle significantly influences the cutting force; furthermore, it does not have a significant effect on the passive force component, while the radial force component is more sensitive to the fibre orientation at up milling, than at down milling. An optimal condition is recommended for zig-zag milling of unidirectional CFRPs.
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Daraj, A. J., and A. H. Al-Zuhairi. "The Combined Strengthening Effect of CFRP Wrapping and NSM CFRP Laminates on the Flexural Behavior of Post-Tensioning Concrete Girders Subjected to Partially Strand Damage." Engineering, Technology & Applied Science Research 12, no. 4 (August 7, 2022): 8856–63. http://dx.doi.org/10.48084/etasr.5008.
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The studies on unbonded post-tensioned concrete members strengthened with Carbon Fiber Reinforced Polymers (CFRPs) are limited and the effect of strengthening on the strain of unbonded pre-stressed steel is not well characterized. Estimating the flexural capacity of unbound post-tensioned members using the design methodology specified in the design guidelines for FRP strengthening techniques of bonded post-tensioned members does not provide a reliable evaluation. This study investigates the behavior of unbonded post-tensioned concrete members with partial strand damage (14.3% and 28.6% damage) and strengthened with CFRP laminates using a near-surface mounted technique with and without U-wrap anchorages. The experimental results showed that the use of CFRP laminates significantly affects strand strain, especially with the use of anchors. The CFRP reinforcement affected flexural strength, crack width, and midspan deflection. However, the flexural stiffness of strengthened members during the serviceability phases is critical as strand damage ratios increase. In comparison with the nondamaged girder, the NSM-CFRP laminates enhanced the flexural capacity by 11% and 7.7% corresponding to strand damage of 14.3% and 28.6% respectively. Additionally, semiempirical equations were proposed to predict the actual strain of unbonded strands whilst considering the effects of FRP laminates. The suggested equations are simple to apply and provide accurate predictions with little variance.
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Im, Kwang-Hee, David K. Hsu, Chien-Ping Chiou, Daniel J. Barnard, Jong-An Jung, and In-Young Yang. "Terahertz Wave Approach and Application on FRP Composites." Advances in Materials Science and Engineering 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/563962.
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Terahertz (THz) applications have emerged as one of the most new powerful nondestructive evaluation (NDE) techniques. A new T-ray time-domain spectroscopy system was utilized for detecting and evaluating orientation influence in carbon fiber-reinforced plastics (CFRPs) composite laminates. Investigation of terahertz time-domain spectroscopy (THz-TDS) was made, and reflection and transmission configurations were studied as a nondestructive evaluation technique. Here, the CFRP composites derived their excellent mechanical strength, stiffness, and electrical conductivity from carbon fibers. Especially, the electrical conductivity of the CFRP composites depends on the direction of unidirectional fibers since carbon fibers are electrically conducting while the epoxy matrix is not. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (α) are derived in reflective and transmission configurations using the terahertz time-domain spectroscopy. Also, for a 48-ply thermoplastic polyphenylene-sulfide-(PPS-) based CFRP solid laminate and nonconducting materials, the terahertz scanning images were made at the angles ranged from0°to180°with respect to the nominal fiber axis. So, the images were mapped out based on the electrical field (E-field) direction in the CFRP solid laminates. It is found that the conductivity (σ) depends on the angles of the nominal axis in the unidirectional fiber.
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KOKLU, UĞUR, and SEZER MORKAVUK. "CRYOGENIC DRILLING OF CARBON FIBER-REINFORCED COMPOSITE (CFRP)." Surface Review and Letters 26, no. 09 (October 17, 2019): 1950060. http://dx.doi.org/10.1142/s0218625x19500604.
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In order to reduce the adverse effects on the environment and economy and to avoid health problems caused by the excessively used cutting lubrications, cryogenic machining is drawing more and more attention. In this work, a novel cryogenic machining approach was applied for drilling of carbon fiber-reinforced polymers (CFRPs). According to this approach, CFRP was dipped into the liquid nitrogen (LN2) and it was machined within the cryogenic coolant directly. Various machinability characteristics on thrust force, delamination damage, tool wear, surface roughness, and topography were compared with those obtained with dry condition. This experimental study revealed that the novel method of machining with cryogenic dipping significantly reduced tool wear and surface roughness but increased thrust force. Overall results showed that the cryogenic machining approach in this study improved the machinability of CFRP.
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İşleyen, Ümmü K., Rahim Ghoroubi, Ömer Mercimek, Özgür Anil, and Recep Tuğrul Erdem. "Behavior of glulam timber beam strengthened with carbon fiber reinforced polymer strip for flexural loading." Journal of Reinforced Plastics and Composites 40, no. 17-18 (April 9, 2021): 665–85. http://dx.doi.org/10.1177/0731684421997924.
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In the last 20 years, the use of wooden structures and their dimensions have gradually increased. The wood application has increased in different structures such as multistory buildings, sports, industrial facilities, road and railway bridges, power transmission lines, and towers. The widespread use and size of wood structures have increased the research on developing special types of wood products supported by composite materials. Laminated wood elements are the leading composite wood materials. Laminated wooden beams allow making much larger openings than standard solid wood structural elements. The development of the sizes and usage areas of wooden structures has increased the capacity of glulam structural elements and reveals the need to improve their performance. Carbon fiber reinforced polymers (CFRPs) are the most suitable options for increasing the bearing capacity values of glulam beams and improving general load–displacement behaviors. In this study, the use of CFRP strips in different layouts to increase glulam wooden beams and the application of CFRP fan-type anchors in the CFRP strip endpoints are the studied variables. Anchored and non-anchored glulam wooden beams reinforced with CFRP strips with different layouts were tested using a three-point bending test. The ultimate load capacity, initial stiffness, displacement ductility ratio, energy dissipation capacity, failure mechanisms, and general load–displacement behavior of wooden beam test specimens were obtained and interpreted as a result of the experiments.
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Böhnke, Philippa Ruth Christine, Iris Kruppke, David Hoffmann, Mirko Richter, Eric Häntzsche, Thomas Gereke, Benjamin Kruppke, and Chokri Cherif. "Matrix Decomposition of Carbon-Fiber-Reinforced Plastics via the Activation of Semiconductors." Materials 13, no. 15 (July 23, 2020): 3267. http://dx.doi.org/10.3390/ma13153267.
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The present study proposed a novel process for the matrix decomposition of carbon-fiber-reinforced plastics (CFRPs). For this purpose, the influence of ultraviolet (UV) radiation paired with semiconductors on CFRP was analyzed. Then, suitable process parameters for superficial and in-depth matrix decomposition in CFRP were evaluated. The epoxy resin was decomposed most effectively without damaging the embedded carbon fiber by using a UV light-emitting diode (LED) spotlight (395 nm, Semray 4103 by Heraeus Noblelight) at a power level of 66% compared to the maximum power of the spotlight. Using a distance of 10 mm and a treatment duration of only 35–40 s achieved a depth of two layers with an area of 750 mm2, which is suitable for technological CFRP repair procedures. In addition to the characterization of the process, the treated CFRP samples were analyzed based on several analytical methods, namely, light microscopy (LM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Subsequently, the prepared carbon fibers (CFs) were tested using filament tensiometry, single filament tensile tests, and thermogravimetric measurements. All analyses showed the power level of 66% to be superior to the use of 96% power. The gentle (“fiber friendly”) matrix destruction reduced the damage to the surface of the fibers and maintained their properties, such as maximum elongation and maximum tensile strength, at the level of the reference materials.
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Choi, Insung, Su-Jin Lee, Dongsig Shin, and Jeong Suh. "Green Picosecond Laser Machining of Thermoset and Thermoplastic Carbon Fiber Reinforced Polymers." Micromachines 12, no. 2 (February 17, 2021): 205. http://dx.doi.org/10.3390/mi12020205.
Full textAbstract:
There has been an increase in demand for the development of lightweight and high-strength materials for applications in the transportation industry. Carbon fiber reinforced polymer (CFRP) is known as one of the most promising materials owing to its high strength-to-weight ratio. To apply CFRP in the automotive industry, various machining technologies have been reported because it is difficult to machine. Among these technologies, picosecond laser beam-induced machining has attracted great interest because it provides negligible heat transfer and can avoid tool wear. In this work, we conducted and compared machining of 2.15 mm-thick thermoset and 1.85 mm-thick thermoplastic CFRPs by using a green picosecond laser. The optimized experimental conditions for drilling with a diameter of 7 mm led to a small taper angle (average ~ 3.5°). The tensile strength of the laser-drilled specimens was evaluated, and the average value was 570 MPa. Our study indicates that green picosecond laser processing should be considered as a promising option for the machining of CFRP with a small taper angle.
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Yu, Yaonan, and Fumio Narita. "Evaluation of Electromechanical Properties and Conversion Efficiency of Piezoelectric Nanocomposites with Carbon-Fiber-Reinforced Polymer Electrodes for Stress Sensing and Energy Harvesting." Polymers 13, no. 18 (September 19, 2021): 3184. http://dx.doi.org/10.3390/polym13183184.
Full textAbstract:
Wireless sensor networks are the future development direction for realizing an Internet of Things society and have been applied in bridges, buildings, spacecraft, and other areas. Nevertheless, with application expansion, the requirements for material performance also increase. Although the development of carbon-fiber-reinforced polymer (CFRP) to achieve these functions is challenging, it has attracted attention because of its excellent performance. This study combined the CFRP electrode with epoxy resin containing potassium sodium niobate piezoelectric nanoparticles and successfully polarized the composite sample. Furthermore, a three-point bending method was applied to compare the bending behavior of the samples. The peak output voltage produced by the maximum bending stress of 98.4 MPa was estimated to be 0.51 mV. Additionally, a conversion efficiency of 0.01546% was obtained. The results showed that the piezoelectric resin with CFRPs as the electrode exhibited stress self-inductance characteristics. This study is expected to be applied in manufacturing self-sensing piezoelectric resin/CFRP composite materials, paving the way for developing stable and efficient self-sensing structures and applications.
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Lee, Yong-Min, Kwan-Woo Kim, and Byung-Joo Kim. "High-Efficiency Carbon Fiber Recovery Method and Characterization of Carbon FIBER-Reinforced Epoxy/4,4′-Diaminodiphenyl Sulfone Composites." Polymers 14, no. 23 (December 4, 2022): 5304. http://dx.doi.org/10.3390/polym14235304.
Full textAbstract:
Globally, the demand for carbon fiber-reinforced thermosetting plastics for various applications is increasing. As a result, the amount of waste from CFRPs is increasing every year, and the EU Council recommends recycling and reuse of CFRPs. Epoxy resin (EP) is used as a matrix for CFRPs, and amine hardeners are mainly used. However, no research has been conducted on recycling EP/4,4’-diaminodiphenyl sulfone (DDS)-based CFRP. In this study, the effect of steam and air pyrolysis conditions on the mechanical properties of re-cycled carbon fiber (r-CF) recovered from carbon fiber-reinforced thermosetting (epoxy/4,4′-diaminodiphenyl sulfone) plastics (CFRPs) was investigated. Steam pyrolysis enhanced resin degradation relative to N2. The tensile strength of the recovered r-CF was reduced by up to 35.12% due to oxidation by steam or air. However, the interfacial shear strength (IFSS) tended to increase by 9.18%, which is considered to be due to the increase in functional groups containing oxygen atoms and the roughness of the surface due to oxidation. The recycling of CFRP in both a steam and an air atmosphere caused a decrease in the tensile strength of r-CF. However, they were effective methods to recover r-CF that had a clean surface and increased IFSS.
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Senu, Norsalwa Aisyah, Ruqayyah Ismail, Norlizan Wahid, Hazrina Ahmad, and Fariz Aswan Ahmad Zakwan. "Compression Behaviour of Concrete Cylinder with Carbon Fibre Reinforced Polymer (CFRP) Confinement." Scientific Research Journal 18, no. 1 (February 28, 2021): 27. http://dx.doi.org/10.24191/srj.v18i1.11394.
Full textAbstract:
Carbon fibre reinforced polymer (CFRP) confinement has always been one of the strengthening methods available for a vulnerable concrete column. This paper presents the compressive behaviour of nine circular concrete cylinders with CFRP confinement. Three different specimen conditions considered; full CFRP confinement, partial CFRP confinement and unconfined (control specimen). Nine concrete cylinders with 100 mm x 200 mm were tested under compression load. It is discovered that full and partial CFRP confinement had improved concrete cylinder ultimate load capacity by 300% and 150% respectively when compared to the unconfined concrete cylinder. With 150% strength enhancement achieved by partial CFRP confined specimen, it is proven that partial CFRP confinement does provide sufficient confinement in enhancing concrete column strength as full CFRP confinement. This finding has led to remarkable discoveries which with lesser CFRP used the functionality of CFRP as strengthening material can still be utilized. Therefore, could contribute significant input to the construction industry in using lesser CFRP for more sustainable material approach.
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Li, Xiao Ke, Guang Ping Hua, and Zhi Hao Wang. "Test of Bond Properties of CFRP with Steel Plate." Applied Mechanics and Materials 438-439 (October 2013): 399–403. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.399.
Full textAbstract:
Combined with the application of a new tensioning device for prestressed CFRP strengthening concrete structures, in order to ensure the safety and determine the reasonable adhesive length of CFRP on steel plate of the anchorage during prestress exerting of CFRP, the tests were carried out to measure the tensile strength of CFRP and the bond strength of CFRP with steel plate considering the influence of different kinds of adhesive. Based on the results, the behaviors of CFRP under tension are analyzed, and the special CFRP glue is chosen as the adhesive of CFRP bonded on steel plate.