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1
Shen, De Jun, Zi Sheng Lin, and Yan Fei Zhang. "Study on the Mechanical Properties of Carbon Fiber Composite Material of Wood." Advanced Materials Research 1120-1121 (July 2015): 659–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1120-1121.659.
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through the use of domestic carbon fiber cloth and combining domestic fast-growing wood of Larch and poplar wood, the CFRP- wood composite key interface from the composite process, stripping bearing performance, Hygrothermal effect, fracture characteristics and shear creep properties to conducted the system research . Fiber reinforced composite (Fiber Reinforced Plastic/Polymer, abbreviation FRP) material by continuous fibers and resin matrix composite and its types, including carbon fiber reinforced composite (Carbon Fiber Reinforce Plastic/Polymer, abbreviation CFRP), glass fiber reinforced composite (Glass Fiber Reinforced Plastic/Polymer, abbreviation GFRP) and aramid fiber reinforced composite (Aramid Fiber Reinforced Plastic/Polymer, abbreviation AFRP). PAN based carbon fiber sheet by former PAN wires, PAN raw silk production high technical requirements, its technical difficulty is mainly manifested in the acrylonitrile spinning technique, PAN precursor, acrylonitrile polymerization process with solvent and initiator ratio. Based on this consideration, the subject chosen by domestic PAN precursor as the basic unit of the CFRP as the object of study.
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Wu, Bo, Shuo Zhang, Fentao Liu, and Ting Gan. "Effects of salt solution on mechanical behaviors of aramid fiber–reinforced polymer (AFRP) sheets and AFRP-to-concrete joints." Advances in Structural Engineering 19, no. 12 (2016): 1855–72. http://dx.doi.org/10.1177/1369433216649389.
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In this article, the mechanical behaviors of four kinds of specimens (i.e. aramid fiber–reinforced polymer sheets, steel-epoxy adhesive joints, concrete cubes, and aramid fiber–reinforced polymer-to-concrete joints) were evaluated, respectively, after the specimens were immersed in 35 g/L NaCl solution for up to 360 days. Test results show that (a) except for the tensile strength of the aramid fiber–reinforced polymer sheet related to an immersion time of 45 days being 5.0% higher than that of the control sheet, the change in the sheet’s tensile strength with the immersion time is not obvious, and the tensile strength of the sheet related to an immersion time of 360 days is almost the same as that of the control sheet; (b) the effect of the salt solution on the modulus of elasticity of the aramid fiber–reinforced polymer sheet is more significant than that on the tensile strength of the sheet, and the elastic modulus of the sheet related to an immersion time of 360 days is 11.1% lower than that of the control sheet; (c) the shear strength of the steel-epoxy adhesive joint experiences severe degradation after being immersed in the salt solution, but the compressive strength of the aged concrete cube is generally larger than that of the control cube; and (d) the maximum local shear stress in the aramid fiber–reinforced polymer-to-concrete joint generally shows a fluctuating increase with the increase in the immersion time, meanwhile the fracture energy of the joint generally increases with the increase in the immersion time, but the failure pattern of the joint with shorter immersion time is different from that with longer immersion time.
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BIN MANDA, MUHAMAD SOFFI, MOHD RUZAIMI BIN MAT REJAB, SHUKUR ABU HASSAN, et al. "Tin Slag Polymer Concrete Strengthening by Basalt and Aramid Fiber Reinforced Polymer Confinement." JOURNAL OF POLYMER MATERIALS 39, no. 3-4 (2023): 241–53. http://dx.doi.org/10.32381/jpm.2022.39.3-4.5.
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This study investigates the potential of Tin Slag Polymer Concrete (TSPC) strengthening through confinement using basalt fiber reinforced polymer (BFRP) and aramid fiber reinforced polymer(AFRP) confinement. TSPC short cylindrical column samples have been wrapped with BFRP and AFRP in a single layer (30 mm overlap) using Sikadur-330 epoxy and final samples were coded as TSPC-UC, TSPC-BF and TSPC-AF for unconfined, BFRP and AFRP for confined respectively. After curing for 30 days at room temperature, compressive test has been performed to know the strength, modulus, strain, fracture energy and failure modes of unconfined and confined TSPC.
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Lee, Jeong Hwan, Jun Cong Ge, and Jun Hee Song. "Study on Burr Formation and Tool Wear in Drilling CFRP and Its Hybrid Composites." Applied Sciences 11, no. 1 (2021): 384. http://dx.doi.org/10.3390/app11010384.
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As contemporary emerging materials, fiber-reinforced plastics/polymers (FRP) are widely used in aerospace automotive industries and in other fields due to their high strength-to-weight ratio, high stiffness-to-weight ratio, high corrosion resistance, low thermal expansion and other properties. Drilling is the most frequently used process in industrial operation for polymer composite laminates, owing to the need for joining structures. However, it is a great challenge for operators to drill holes in FRP materials, due to the non-homogenous and anisotropic properties of fibers. Various damages, such as delamination, hole shrinkage, and burr and tool wear, occur due to the heterogeneous and anisotropic nature of composite laminates. Therefore, in this study, carbon fiber reinforced polymer (CFRP)/aramid fiber reinforced polymer (AFRP) hybrid composites (C-AFRP) were successfully synthesized, and their drilling characteristics, including burr generation and tool wear, were also mainly investigated. The drilling characteristics of CFRP and C-AFRP were compared and analyzed for the first time under the same operating conditions (cutting tool, spindle speed, feed rate). The experimental results demonstrated that C-AFRP had higher tensile strength and good drilling characteristics (low thrust and less tool wear) compared with CFRP. As a lightweight and high-strength structural material, C-AFRP hybrid composites have great potential applications in the automobile and aerospace industries after the slight processing of burrs generated during drilling.
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Karvanis, Konstantinos, Soňa Rusnáková, Ondřej Krejčí, and Alena Kalendová. "Thermal analysis of postcured aramid fiber/epoxy composites." REVIEWS ON ADVANCED MATERIALS SCIENCE 60, no. 1 (2021): 479–89. http://dx.doi.org/10.1515/rams-2021-0036.
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Abstract In this study, aramid fiber-reinforced polymer (AFRP) composites were prepared and then postcured under specific heating/cooling rates. By dynamic mechanical analysis, the viscoelastic properties of the AFRP composites at elevated temperatures and under various frequencies were determined. Thermomechanical analysis (TMA), in the modes of creep-recovery and stress–relaxation tests, was also performed. Furthermore, differential scanning calorimetry was also used, and the decomposition of the AFRP composites, aramid fibers, and pure postcured epoxy, in two different atmospheres, namely, air atmosphere and nitrogen (N2) atmosphere, was explored by the thermogravimetric analysis (TGA). From this point of view, the aramid fibers showed remarkably thermal resistance, in N2 atmosphere, and the volume fraction of fibers (Φf) was calculated to be Φf = 51%. In the TGA experiments, the postcured AFRP composites showed very good thermal resistance, both in air and N2 atmosphere, and this characteristic in conjunction with their relatively high T g, which is in the range of 85–95°C, depending on the frequency and the determination method, classifies these composites as potential materials in applications where the resistance in high temperatures is a required characteristic.
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Karaman, Abdurrahman, Mehmet Nuri Yildirim, and Onder Tor. "BENDING CHARACTERISTICS OF LAMINATED WOOD COMPOSITES CONSTRUCTED WITH BLACK PINE WOOD AND ARAMID FIBER REINFORCED FABRIC." WOOD RESEARCH 66(2): 2021 66, no. 2 (2021): 309–20. http://dx.doi.org/10.37763/wr.1336-4561/66.2.309320.
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The aim of this study was to determine the 4-point bending strength and modulus of elasticity in bending of Black pine wood laminated materials reinforced with aramid fiber was bonded using epoxy or polyurethane glues separately. The samples were prepared in accordance with the TS 5497 EN 408 (2006). The results of the study determined that the highest value for static bending strength was found in the laminated wood samples (83.94 N.mm-2) that were prepared using inter-layer aramid fiber reinforced polymer (AFRP) and epoxy glue. The highest value of modulus of elasticity in bending was found in the samples prepared with inter-layer epoxy and AFRP (10311.62 N.mm-2). It was observed that the samples parallel to the glue line of the laminated material showed higher performance compared to those perpendicular to the glue line. The data obtained as a result of this study demonstrated that aramid fiber reinforced Black pine wood laminated materials can be used in the building industry as building materials.
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Benmokrane, Brahim, Burong Zhang, Adil Chennouf, and Radhouane Masmoudi. "Evaluation of aramid and carbon fibre reinforced polymer composite tendons for prestressed ground anchors." Canadian Journal of Civil Engineering 27, no. 5 (2000): 1031–45. http://dx.doi.org/10.1139/l00-090.
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This paper presents the tension and bond properties of commercially available Aramid fibre reinforced polymer (AFRP) and carbon fibre reinforced polymer (CFRP) rods and their uplift and sustained loading behaviour as ground anchor tendons. Variables for the tests were tendon type and constituent, grout type, and bond or fixed anchor length. Test results indicated that the tension properties of fibre reinforced polymer (FRP) rods were close to the reported data. The surface geometry of FRP rods and the properties of filling grouts influenced the pullout behaviour and bond strength of grouted FRP rods. CFRP Carbon Fiber Composite Cable and Leadline anchors had a higher uplift capacity but lower creep displacement than AFRP Arapree and Technora anchors. The tested CFRP monorod and FRP multirod anchors with a 1000 mm fixed anchor length exhibited an acceptable uplift behaviour according to existing codes. Creep behaviour appeared to control the long-term uplift capacity of prestressed FRP ground anchors. The recommended working load for post-tensioned FRP ground anchors is 0.40 fpu for AFRP rods and 0.50fpu for CFRP rods, where fpu is the ultimate load or strength of the anchor tendon.Key words: FRP, tendon, bond stress, anchorage, grouted anchor, fixed anchor length, free anchor length, slip, creep.
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P, Gnanamoorthy, Butti Venkatesh, D. Rajesh, Vittel Rao, Ram Subbiah, and Aanchal Dhawan. "Effect of Aramid Fiber reinforced polymer and Carbon Fiber reinforced polymer Wrappings on the Mechanical Properties of M30 Concrete." E3S Web of Conferences 588 (2024): 03023. http://dx.doi.org/10.1051/e3sconf/202458803023.
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Fiber-reinforced polymer is an advanced composite material composed of fibers and resin. It is a cost-effective and efficient material for repairing both existing and new structures. Additionally, these composite materials exhibit exceptional mechanical properties, including strength, Impact resistance, stiffness, load-bearing capacity and flexibility. This experimental research aims to investigate the behaviour of AFRP and CFRP materials wrapped in different layers when subjected to mechanical and non- destructive testing. Concrete confirming to the M30 grade is used for this experimental study. To ensure consistent concrete quality throughout the study, various test specimens were cast and subjected to standard tests, including compression tests, split tensile tests, modulus of rupture, modulus of elasticity, and impact tests on hardened concrete. Additionally, Rebound hammer and UPV test are two important NDT methods used to determine the quality of concrete. The tests were conducted using various specimens, including cubes (150mmx150mm), cylinders (150mmx300mm), prisms (100mmx100mmx500mm), and discs (63.5mm x 152.4mm). The experimental results indicate that concrete specimens confined with CFRP exhibit higher strength compared to those confined with AFRP and unconfined specimens, in both single and double ply wrappings.
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Bellini, Costanzo, Rosario Borrelli, Vittorio Di Cocco, et al. "Titanium/FRP hybrid sandwich: in-plane flexural behaviour of short beam specimens." Frattura ed Integrità Strutturale 18, no. 69 (2024): 18–28. http://dx.doi.org/10.3221/igf-esis.69.02.
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Adopting novel sandwich structures with FRP (Fibre Reinforced Polymer) skins and a metallic lattice core, both of which have high specific strength and stiffness, is one way to achieve better mechanical performance while remaining lightweight. Flexural stress is a load pattern that frequently occurs in the structural frame components of automobiles; nonetheless, while the in-plane load scheme has scarcely been examined, the out-of-plane load one has. As a result, the former configuration received consideration in this work. Moreover, short beam specimens were taken into account. The mechanical response of specimens with three different kinds of composite materials as skin material was analysed. The skins were made of CFRP (Carbon Fiber Reinforced Polymer), with two different weaving styles, and AFRP (Aramid Fiber Reinforced Polymer). All-titanium specimens were studied, too. Similar maximum loads and maximum displacement at break were recorded for both CFRP and AFRP specimens, while the all-titanium one resulted stronger. In terms of the load-displacement curves, the first section featured an initial linear phase, followed by a minor load drop, likely attributed to the breakage of fibres. The CFRP specimens showed a sharp fracture of the skin fibres, while for the AFRP, a fraying was observed.
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Jokūbaitis, Aidas, and Juozas Valivonis. "Transfer Length vs. Slip of Prestressed Fiber-Reinforced Polymer Reinforcement." Polymers 15, no. 5 (2023): 1190. http://dx.doi.org/10.3390/polym15051190.
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A comprehensive analysis of the relationship between transfer length and slip of different types of prestressed fiber reinforced polymer (FRP) reinforcement is provided. The results of the transfer length and slip together with the main influencing parameters of approximately 170 specimens prestressed with different FRP reinforcement were collected. After the analysis of a larger database of transfer length versus slip, new bond shape factors were proposed for carbon fiber composite cable (CFCC) strands (α = 3.5) and carbon fiber reinforced polymer (CFRP) bars (α = 2.5). It was also determined that the type of prestressed reinforcement has an influence on the transfer length of the aramid fiber reinforced polymer (AFRP) bars. Therefore, α = 4.0 and α = 2.1 were proposed for AFRP Arapree bars and AFRP FiBRA and Technora bars, respectively. Moreover, the main theoretical models are discussed together with the comparison of theoretical and experimental transfer length results based on the slip of reinforcement. Additionally, the analysis of the relationship between transfer length and slip and the proposed new values of the bond shape factor α have the potential to be introduced in the production and quality control processes of precast prestressed concrete members and to stimulate additional research that increases the understanding of the transfer length of FRP reinforcement.
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Hou, Min, Jiangfeng Dong, Lang Li, Shucheng Yuan, and Qingyuan Wang. "Experimental Research on AFRP Reinforced Recycled Steel Tube Columns Subjected to Axial Compression." Advanced Composites Letters 26, no. 6 (2017): 096369351702600. http://dx.doi.org/10.1177/096369351702600605.
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In order to make an effective use of the recycled aggregate concrete (RAC), a total of six steel tube RAC columns and six basalt fiber (BF) reinforced RAC columns, including six columns that were externally strengthened with aramid fiber reinforced polymer (AFRP) sheets, were fabricated and tested. This were to provide a strengthening solution to upgrade the load carrying capacity, ductility and rigidity of the RAC filled steel tube columns. Besides, the recycled coarse aggregate (RCA) replacement ratios for production of RAC was analyzed. The results show that the load carrying capacity and ultimate displacements of the RAC filled ST columns could be improved greatly by adding of basalt fiber, especially for the specimens with 50% and 100% RCA replacement ratio. The similar result was also found for the specimens strengthened with AFRP reinforcement, along with the stiffness of the columns were enhanced obviously. Moreover, the highest improving on the load carrying capacity, stiffness and ultimate displacement was found in the specimens both reinforced by adding of BF and strengthening of AFRP. However, the failure modes of the specimens with BF reinforced RAC gave a higher deformability than the one with AFRP strengthening arrangement.
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Zhang, Shuo, Chun Lin Liu, Wen Zhu, et al. "Durability Performances of Aramid Fiber Reinforced Polymer as Reinforcement Material for Concrete Structures in Cold Regions." Key Engineering Materials 853 (July 2020): 171–76. http://dx.doi.org/10.4028/www.scientific.net/kem.853.171.
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A series of tests were conducted to investigate the mechanical performances of aramid fiber reinforced polymer (AFRP) and its epoxy resin matrix after 0, 20, 40, 60 and 80 freeze-thaw cycles in the dry air, respectively. After a given number of freeze-thaw cycles, the residual tensile strength and elastic modulus of AFRP specimens were measured, and the lap-shear strength of epoxy resin adhesive specimens was gained. Test results show that: (1) Variation of the elastic modulus of AFRP with the increasing of the freeze-thaw cycles exhibits the same tendency as the tensile strength did. They increase in the first 20 to 40 cycles and then decrease till the end of 80 cycles; (2) The tensile strength and elastic modulus of AFRP decreases by 5.1% and 8.2%, respectively, after 80 cycles as compared with that kept in the laboratory environments. However, the effect of the freeze-thaw cycling in the dry air on the tensile properties of CFRP is very limited within 80 cycles; (3) The freeze-thaw cycling in the dry air of this study has an adverse effect on the adhesive property of the epoxy resin, which could be regarded as the evidence for the degradation of the interface between aramid/carbon fiber and matrix.
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Bakalarz, Michał Marcin, and Paweł Grzegorz Kossakowski. "Ductility and Stiffness of Laminated Veneer Lumber Beams Strengthened with Fibrous Composites." Fibers 10, no. 2 (2022): 21. http://dx.doi.org/10.3390/fib10020021.
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The paper presents the results of experimental research on unstrengthened and strengthened laminated veneer beams subjected to 4-point bending. Aramid, glass and carbon sheets with high tensile strength (HS) and ultra-high modulus of elasticity (UHM) glued to external surfaces with an epoxy resin adhesive were used as reinforcement. Two reinforcement layouts were used: (1) sheets glued along the bottom surface and (2) sheets glued to the bottom and side surfaces. Based on the test results, the flexural strength, flexural ductility and stiffness were estimated. Compared to the reference beams, the maximum bending moment was higher by 15%, 20%, 30% and by 16%, 22% and 35% for the Aramid Fiber Reinforced Polymers (AFRP), Glass Fiber Reinforced Polymers (GFRP) and Carbon Fiber Reinforced Polymers (CFRP) HS sheets, respectively. There was no significant increase in the flexural bending capacity for beams reinforced with UHM CFRP sheets. Similar values of bending ductility indices based on deflection and energy absorption were obtained. Higher increases in ductility were observed for AFRP, GFRP and CFRP HS sheets in “U” reinforcement layout. The average increase in bending stiffness coefficient ranged from 8% for AFRP sheets to 33% for UHM CFRP sheets compared to the reference beams.
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Liu, Yi, Yue Ting Yang, Jing Zeng, and Ling Chen. "Experimental Study of AFRP-Confined Square and Circular Concrete Columns Using Fiber Bragg Grating Sensors." Materials Science Forum 982 (March 2020): 175–80. http://dx.doi.org/10.4028/www.scientific.net/msf.982.175.
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An experimental investigation on square and circular high-strength concrete short columns confined with aramid fiber-reinforced polymer (AFRP) sheets was conducted in this study. Fiber Bragg grating sensors have been applied successfully in monitoring of the strains of the AFRP-confined square and circular concrete columns. The experimental results demonstrate that two types of axial force-strain curves were observed depending on the form of the column. Results show fiber Bragg grating sensors have good repeatability and the ultimate load of the circular concrete column is larger than that of the square concrete column. The interlaminar strains of AFRP and high-strength concrete have also been attained. It helps to analyze the constraint effect of the concrete column and compute the ultimate load of the square and circular concrete column.
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Kim, Min Sook, Young Hak Lee, Heecheul Kim, Andrew Scanlon, and Junbok Lee. "Flexural behavior of concrete beams reinforced with aramid fiber reinforced polymer (AFRP) bars." Structural Engineering and Mechanics 38, no. 4 (2011): 459–77. http://dx.doi.org/10.12989/sem.2011.38.4.459.
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Jokūbaitis, Aidas, and Juozas Valivonis. "An Analysis of the Transfer Lengths of Different Types of Prestressed Fiber-Reinforced Polymer Reinforcement." Polymers 14, no. 19 (2022): 3931. http://dx.doi.org/10.3390/polym14193931.
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The main aim of this paper is to provide a broader analysis of the transfer lengths of different types of fiber-reinforced polymers (FRPs) and to provide corrections to the existing theoretical models. Therefore, this paper presents a description of the main factors that influence the transfer lengths of different types of FRPs based on experimental results found in the literature. A database of more than 300 specimens was compiled with the results of the transfer lengths of different FRPs and the main influencing parameters. The analysis of the database results showed that the transfer length of the carbon fiber composite cable (CFCC) strands depends on the type of prestressed reinforcement release. Therefore, in this article, the new coefficient αt = 2.4 is proposed for the transfer length of suddenly released CFCC strands. Additionally, the transfer length of the aramid fiber reinforced polymer (AFRP) depends on its surface conditions. Therefore, new coefficients αt = 1.5 and αt = 4.0 are also proposed for the transfer lengths of smooth braided and sanded and rough AFRP bars, respectively. Furthermore, the proposed coefficients αt = 2.6, αt = 1.9, and αt = 4.8 found in the literature were validated with the analysis of a larger database of the transfer lengths of glass fiber-reinforced polymer (GFRP) bars, carbon fiber-reinforced polymer (CFRP) bars, and gradually released CFCC strands, respectively. Moreover, the main existing theoretical models are presented, and the comparison of theoretical and experimental transfer length results is discussed. However, the low number of specimens prestressed with basalt fiber-reinforced polymer (BFRP) bars prevented the deeper analysis of the results. the analysis of the transfer length and the proposed new values of the coefficient αt provides possibilities for adapting it to design codes for engineering applications and performing additional research that fills the missing gaps in the field.
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Djafar-Henni, Imane, and Amina Sadouki. "Predictive modeling of aramid fiber reinforced polymer confinement for improved compressive strength in circular concrete columns." STUDIES IN ENGINEERING AND EXACT SCIENCES 5, no. 2 (2024): e5582. http://dx.doi.org/10.54021/seesv5n2-018.
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Fiber Reinforced Polymers (FRPs) have gained significant attention in the field of structural engineering due to their high strength-to-weight ratio, corrosion resistance, and ease of application. Among various types of FRPs, Aramid Fiber Reinforced Polymers (AFRP) stand out for their exceptional tensile strength and durability, making them ideal for confining concrete columns to enhance their compressive strength. This study aims to leverage these benefits by predicting the compressive strength of circular concrete columns confined with AFRP using Artificial Neural Networks (ANNs). To develop and validate the ANN model, a comprehensive dataset consisting of 190 samples was employed during the training phase, while an additional set of 33 samples was used for validation. The performance and predictive capabilities of the ANN model were thoroughly assessed through extensive testing and direct comparison with experimental results, which demonstrated the model’s high accuracy and reliability. Moreover, a detailed parametric study was conducted to examine the influence of various input parameters on the compressive strength prediction. The findings from this study offered significant insights into the effects of various parameters on the predicted outcomes, including column diameter, unconfined concrete strength and strain, as well as AFRP confinement parameters such as thickness, tensile strength, elastic modulus, and strain. Notably, the sensitivity analysis underscored the profound impact of the tensile strength of AFRP on the ANN model's predictive accuracy. The research offers a robust tool for engineers, enabling them to estimate the compressive strength of AFRP-confined circular concrete columns accurately. Additionally, it provides crucial insights that are instrumental in optimizing the design and application of AFRP wrapping or tube-encased methods within the realm of structural engineering. Overall, this research marks a significant step forward in the field of structural engineering, providing a valuable predictive tool and offering insights that can lead to the development of more resilient and sustainable infrastructure.
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Sinh, Le Huy, Masato Komuro, Tomoki Kawarai, and Norimitsu Kishi. "Failure Modes of Reinforced Concrete Beams Strengthened in Flexure with Externally Bonded Aramid Fiber-Reinforced Polymer Sheets under Impact Loading." Buildings 12, no. 5 (2022): 584. http://dx.doi.org/10.3390/buildings12050584.
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This paper focuses on the aramid fiber-reinforced polymer (AFRP) sheet bonding method to investigate the influences of the sheet volume and input impact energy on the failure modes of strengthened RC beams. The drop-weight impact loading tests were conducted on RC beams strengthened with AFRP sheets. The sheet volume was investigated, varying from 415 to 1660 g/m2. The impact force was generated by dropping a 300 kg steel weight onto the midspan of the beams from different heights (0.5, 1.0, 2.0, 2.5, 3.0, and 3.5 m), and the weight’s drop height was raised until the sheets were debonded or ruptured. As a reference beam, nonstrengthened beams were also evaluated. The following are the findings of this research. (1) In the event of impact loading, the impact resistance capacity of strengthened beams can be enhanced by up to 85% by applying the AFRP sheet bonding method; however, (2) in the case of relatively large impact energy, the impact resistance capacity may not always be remarkable. (3) Depending on the sheet volume, the failure mechanism of the AFRP-strengthened beams was classified into two types: sheet debonding and sheet rupturing. Furthermore, (4) increasing the sheet volume may not improve the debonding of the AFRP sheet of the strengthened beams.
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Song, Hengwen, Hui Yang, and Shi Zhang. "Study on Dynamic Behavior of AFRP-Wrapped Circular Concrete Specimens under Repeated Impacts." Polymers and Polymer Composites 25, no. 1 (2017): 103–12. http://dx.doi.org/10.1177/096739111702500114.
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A series of damage tests and axially repeated compressive tests with high strain rates were conducted to investigate the behavior of aramid fiber reinforced polymer (AFRP) wrapped concrete under repeated impacts. The relation between damage condition and variables such as impact number and polymer thickness were examined. The tests were performed using a 100 mm diameter Split Hopkinson Pressure Bar (SHPB) apparatus and a nonmetal supersonic test meter. Various AFRP layers were applied to produce varied confinement ratios. The experimental results indicated that the AFRP-wrapped concrete exhibited excellent performance in resisting repeated impacts. Also, the specimens maintained their shapes and bearing capacity after multiple impacts with a mean strain rate of 50 s−1. No distinct decline was observed from the history of peak stress and impact toughness in AFRP-wrapped concrete. Moreover, additional AFRP layers significantly decreased the impact damage on the core concrete, as reflected by the different strain rate histories in damage progression.
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Durga Prasada Rao, V., Sk R. S. Mahaboob Ali, Sk M. Z. M. S. Ali, and B. S. Santhoshi. "Analysis Of Delamination During Drilling Process Of Aramid Fibre Reinforced Polymers." Journal of Physics: Conference Series 2765, no. 1 (2024): 012016. http://dx.doi.org/10.1088/1742-6596/2765/1/012016.
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Abstract Aramid Fibre Reinforced Polymer (AFRP) is a modern engineering material which is highly versatile in nature. These materials are usually used to produce impact resistant structures. Aramids have high modulus, tensile strength, stiffness, and low weight density. AFRP, under cyclic loading, shows good performance. As far as textiles and concrete structures are considered, AFRP is one of the best fiber-reinforced composites. Delamination is a failure mode that causes fracture of a variety of materials including concrete and laminate composites. A material, in general, fractures into layers due to delamination effect, i.e., separation into its constituent layers. In the present study, the AFRP polymer is prepared by hand layup method, drilling operation is done on the composite under different machining conditions, measurements regarding delamination are taken using a tool room microscope, and delamination factor is calculated by using a suitable equation. Rate of feed, spindle speed and diameter of drill are the drilling parameters under consideration. Each of these parameters are considered at three different levels. A fully crossed design consisting of 27 tests is considered to conduct experiments. The results of different experiments are analyzed statistically using Fisher variance analysis (ANOVA) to determine the impact of variables of drilling on the delamination factor. The main effects plots disclose that the lowest delamination factor is obtained for a rate of feed of 0.4 mm/rev, a speed of spindle of 1000 rpm and for a drill diameter of 15 mm. It is also noted that the delamination factor increases as the speed of spindle and diameter decreases. The interaction plot of rate of feed-spindle speed indicates that the interaction has moderate effect on delamination factor, whereas interaction plot of rate of feed-diameter represents that the rate of feed on delamination factor banks on level of drill diameter, and interaction plot of speed of spindle speed-diameter of drill demonstrates that the interaction has moderate impact on delamination factor. Also, regression analysis is done to establish the general linear model relating delamination factor and the drilling parameters under consideration.
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Lin, Ye, Junying Min, Hao Teng, Jianping Lin, Jiahao Hu, and Nanjie Xu. "Flexural Performance of Steel–FRP Composites for Automotive Applications." Automotive Innovation 3, no. 3 (2020): 280–95. http://dx.doi.org/10.1007/s42154-020-00109-x.
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AbstractThe design of hybrid structure offers an attractive solution to enhance strength and structural stiffness as well as to achieve lightweight effect and cost reduction. The applications of steel–FRP (fiber-reinforced polymer) composites in transportation and civil engineering have been comprehensively reviewed. In order to apply hybrid structures to car body parts such as B-pillar, flexural performance of steel–FRP composites is investigated by means of three-point bending test in this study. An analytical model is deduced to calculate the initial stiffness, the bending load and the energy absorption of steel–FRP composites. Steel–CFRP (carbon fiber-reinforced polymer) and steel–AFRP (aramid fiber-reinforced polymer) composites are experimentally studied and discussed. The results demonstrate that the steel–FRP composites exhibit significantly higher load-carrying capabilities and initial stiffnesses along with larger energy absorptions in the bending process compared to the single steel sheet.
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Deng, Zong Cai, Jian Hui Li, and He Fei Lin. "Experimental Study on Flexural Performance of Corroded RC Beams Strengthened with AFRP Sheets." Key Engineering Materials 405-406 (January 2009): 343–49. http://dx.doi.org/10.4028/www.scientific.net/kem.405-406.343.
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In order to investigate the strengthening effects of aramid fiber reinforced polymer (AFRP) sheets on the flexural performance of the corroded beams, the flexural behaviors of corroded RC beams strengthened with AFRP sheets under different degrees of corrosion (minor: reinforcement mass loss is 2.0％, medium: reinforcement mass loss is 6.0％) are researched experimentally in this paper, and compared with that of the control beams (un-corroded) and un-strengthened corroded beams. The results show that，compared with un-strengthened corroded beams under same degrees of corrosion, the cracking load, yield load and ultimate load of minor corroded RC beam strengthened with AFRP sheets is respectively increased by 20%, 27% and 60%, and increased by 15%, 36% and 83% for medium corroded RC beam strengthened with AFRP sheets respectively; The ultimate deflection of the medium corroded beam strengthened with AFRP sheets is 166% larger than that of corroded un-strengthened beam. AFRP sheets can improve significantly the bearing capacity and deformation for corroded RC beams.
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Zhang, Huizhong, Haitao Li, Ileana Corbi, et al. "AFRP Influence on Parallel Bamboo Strand Lumber Beams." Sensors 18, no. 9 (2018): 2854. http://dx.doi.org/10.3390/s18092854.
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The mechanical properties of parallel bamboo strand lumber beams could be improved by aramid fiber reinforced polymer (AFRP). So far, no investigation has been conducted on the strengthening of engineering bamboo beams using AFRP. In order to study the efficiency of AFRP reinforcement on parallel bamboo strand lumber beams, 13 beams had been tested and analyzed. Strain gauges and Laser Displacement Sensors were used for the tests. By sensing the strain and deformation data for the specimens under the applied loads, the results showed that AFRP can effectively improve the flexural mechanical properties of parallel bamboo strand lumber beams. However, this reinforcement cannot increase the deflection of bamboo beams indefinitely. When the cloth ratio was 0.48, the deflection of the specimens reached its maximum. With the increase of cloth ratio, the stiffness of parallel bamboo strand lumber beams was increasing. When the cloth ratio reached 0.72%, compared with the un-reinforced specimen, the stiffness increased by 15%. Therefore, it can be inferred that bonding AFRP on the considered specimens can increase the stiffness of parallel bamboo strand lumber beams. The ductility of the specimen can be effectively enhanced by adopting the AFRP provision.
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Akıncıoğlu, Sıtkı. "Investigation of effect of abrasive water jet (AWJ) machining parameters on aramid fiber-reinforced polymer (AFRP) composite materials." Aircraft Engineering and Aerospace Technology 93, no. 4 (2021): 615–28. http://dx.doi.org/10.1108/aeat-11-2020-0249.
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Purpose The purpose of this study was to optimize the surface roughness (Ra), delamination damage at the hole entrance (FdT) and at the hole exit (FdB) and kerf angle (K) in the drilling of aramid fiber-reinforced polymer (AFRP) composite material using abrasive water jet (AWJ) machining. Design/methodology/approach The AFRP composite was produced by the vacuum infusion method. The drilling experiments were performed on an AWJ machine using a three-axis computerized numerical control system. Machine processing parameters were determined as water pressure (2,000, 3,000 and 4,000 bar), stand-off distance (2, 4 and 6 mm) and traverse feed rate (150, 250 and 350 mm/min). Optimization of processing parameters in the drilling experiments was carried out according to the Taguchi L27 (33) orthogonal array. In addition, gray relational analysis (GRA) was used to analyze the complex uncertainty affecting the results. Findings Results of the drilling operations demonstrated that water pressure (P) was the most effective parameter, with 65.3%, 65.2%, 49.8% and 52.1% contribution rates for Ra, FdT, FdB and K, respectively. Practical implications Reliable results have been obtained with Taguchi-based GRA while drilling AFRP composite material using AWJ. Significant results have been achieved to increase the hole quality in the drilling of AFRP composite material. Originality/value The new approach is to present more detailed analysis by using Taguchi method and multi-decision Taguchi-based gray relation analysis in AFRP composite material drilling using AWJ. Thus, time and experiment costs are saved.
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Vincent, Thomas, and Togay Ozbakkaloglu. "Influence of Fiber Type on Behavior of High-Strength Concrete-Filled FRP Tubes under Concentric Compression." Applied Mechanics and Materials 438-439 (October 2013): 240–45. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.240.
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This paper presents results from an experimental study on the behavior of circular high-strength concrete (HSC)-filled fiber reinforced polymer (FRP) tubes (HSCFFTs). Concrete-filled FRP tubes (CFFTs) have received significant research attention over the last two decades and experimental investigations into the axial behavior are abundant for normal-strength concretes (NSC) confined by either carbon FRP (CFRP) or class FRP (GFRP). However, the same cannot be said for CFFTs filled with HSC or manufactured with other fiber types such as aramid or high-modulus carbon FRP (AFRP and HMCFRP), where experimental testing is very limited. To address this research gap, this study examined the compressive behavior of 24 test specimens prepared with three different fiber types (CFRP, HMCFRP and AFRP) and manufactured with HSC. The experimentally recorded stress-strain relationships are presented graphically and the influence of fiber type and other key experimental outcomes are discussed. The results indicate that fiber type has a significant influence on the axial compressive behavior of HSCFFTs.
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Saafi, Mohamed, and Houssam Toutanji. "Flexural capacity of prestressed concrete beams reinforced with aramid fiber reinforced polymer (AFRP) rectangular tendons." Construction and Building Materials 12, no. 5 (1998): 245–49. http://dx.doi.org/10.1016/s0950-0618(98)00016-6.
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Joyklad, Panuwat, Ekkachai Yooprasertchai, Pongsak Wiwatrojanagul, Krisada Chaiyasarn, Nazam Ali, and Qudeer Hussain. "Use of Natural and Synthetic Fiber-Reinforced Composites for Punching Shear of Flat Slabs: A Comparative Study." Polymers 14, no. 4 (2022): 719. http://dx.doi.org/10.3390/polym14040719.
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Over the last two decades, considerable attention has been devoted to the strengthening of sub-standard flat-slab constructions. With the evolution of composite materials and an increasing emphasis on the economical and sustainable use of natural fibers, many researchers have utilized them in the strengthening of flat flabs mitigating punching failures. This study aims at investigating and comparing the behavior of flat slabs strengthened with post-installed composite and natural reinforcements. An experimental program was devised consisting of eight flat-slab specimens. One specimen was tested in as-built condition to provide a reference. The remaining specimens were strengthened with Carbon Fiber-Reinforced Polymer (CFRP), Aramid Fiber-Reinforced Polymer (AFRP), and sisal rods. The pattern of post-installed rods was varied as single line, double line, and star shapes around the column. The results indicated that the single-line pattern could only enhance the maximum sustained load by up to 6% compared to that of the reference specimen. On the contrary, double line and star shape configurations resulted in a substantial increase in the maximum sustained load. An analytical assessment of ACI 318-19 provisions resulted in an over-estimation of the shear strengths of CFRP- and AFRP-strengthened slabs. Furthermore, the same provisions led to lower yields than experimental shear strengths for sisal-strengthened slabs.
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Mirdarsoltany, Mohammadamin, Farid Abed, Reza Homayoonmehr, and Seyed Vahid Alavi Nezhad Khalil Abad. "A Comprehensive Review of the Effects of Different Simulated Environmental Conditions and Hybridization Processes on the Mechanical Behavior of Different FRP Bars." Sustainability 14, no. 14 (2022): 8834. http://dx.doi.org/10.3390/su14148834.
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When it comes to sustainability, steel rebar corrosion has always been a big issue, especially when they are exposed to harsh environmental conditions, such as marine and coastal environments. Moreover, the steel industry is to blame for being one of the largest producers of carbon in the world. To supplant this material, utilizing fiber-reinforced polymer (FRP) and hybrid FRP bars as a reinforcement in concrete elements is proposed because of their appropriate mechanical behavior, such as their durability, high tensile strength, high-temperature resistance, and lightweight-to-strength ratio. This method not only improves the long performance of reinforced concrete (RC) elements but also plays an important role in achieving sustainability, thus reducing the maintenance costs of concrete structures. On the other hand, FRP bars do not show ductility under tensile force. This negative aspect of FRP bars causes a sudden failure in RC structures, acting as a stumbling block to the widespread use of these bars in RC elements. This research, at first, discusses the effects of different environmental solutions, such as alkaline, seawater, acid, salt, and tap water on the tensile and bonding behavior of different fiber-reinforced polymer (FRP) bars, ranging from glass fiber-reinforced polymer (GFRP) bars, and basalt fiber-reinforced polymer (BFRP) bars, to carbon fiber-reinforced polymer (CFRP) bars, and aramid fiber-reinforced polymer (AFRP) bars. Furthermore, the influence of the hybridization process on the ductility, tensile, and elastic modulus of FRP bars is explored. The study showed that the hybridization process improves the tensile strength of FRP bars by up to 224% and decreases their elastic modulus by up to 73%. Finally, future directions on FRP and hybrid FRP bars are recommended.
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Shawki Ali, Noura Khaled, Sameh Youssef Mahfouz, and Nabil Hassan Amer. "Flexural Response of Concrete Beams Reinforced with Steel and Fiber Reinforced Polymers." Buildings 13, no. 2 (2023): 374. http://dx.doi.org/10.3390/buildings13020374.
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This paper numerically investigates the flexural response of concrete beams reinforced with steel and four types of Fiber-Reinforced Polymers (FRP), i.e., Carbon FRP (CFRP), Glass FRP (GFRP), Aramid FRP (AFRP), and Basalt FRP (BFRP). The flexural responses of forty beams with two boundary conditions (simply supported and over-hanging beams) were determined using ABAQUS. Subsequently, the finite element models were validated using experimental results. Eventually, the impact of the reinforcement ratios ranging between 0.15% and 0.60% on the flexural capacity, crack pattern, and fracture energy were investigated for all beams. The results revealed that, for the low reinforcement ratios, the flexural performance of CFRP significantly surpassed that of steel and other FRP types. As the reinforcement ratio reached 0.60%, the steel bars exhibited the best flexural performance.
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Li, Yeou-Fong, Bo-Yu Chen, Jin-Yuan Syu, et al. "A Constitutive Model for Circular and Square Cross-Section Concrete Confined with Aramid FRP Laminates." Buildings 13, no. 11 (2023): 2895. http://dx.doi.org/10.3390/buildings13112895.
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Fiber-reinforced polymer (FRP) has been used for seismic retrofitting and structural reinforcement over recent decades. Numerous researchers have created stress–strain models based on experimental data to predict the mechanical properties of FRP-confined concrete. In this study, circular and square cross-section specimens with different design concrete strength were prepared, and the compressive strength of the specimens confined with different layers of aramid FRP (AFRP) were measured in compressive tests. A constitutive model was proposed to simulate the uniaxial compressive stress–strain relationship of the AFRP-confined concrete, which was derived from the Mohr–Coulomb failure envelope theory, and the corresponding axial strain was determined from the regression analysis. The internal friction angle of the proposed constitutive model was determined for the cylindrical concrete specimens confined with one and two layers of AFRP. The compressive strength of one and two layers of AFRP-confined concrete specimens were used to obtain the parameters of the constitutive model; the absolute average error between experimental and predicted compressive strength was 7.01%. Then, the constitutive model was used to predict the strength of a three-layer AFRP-confined concrete specimen, and the absolute average error was 4.95%. The cross-sectional shape coefficient of the square concrete specimen was obtained analytically. Substituting the cross-sectional shape coefficient into the proposed constitutive model, the average absolute error of the square cross-section concrete specimen was about 3.84%. The results indicated that the proposed constitutive model can predict the compressive strength of circular and square cross-section concrete specimens confined with AFRP.
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Seyhan, Engin, Caglar Goksu, Ahmet Uzunhasanoglu, and Alper Ilki. "Seismic Behavior of Substandard RC Columns Retrofitted with Embedded Aramid Fiber Reinforced Polymer (AFRP) Reinforcement." Polymers 7, no. 12 (2015): 2535–57. http://dx.doi.org/10.3390/polym7121527.
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Oprişan, Gabriel, Ioana-Sorina Enţuc, Petru Mihai, et al. "Behaviour of Rubberized Concrete Short Columns Confined by Aramid Fibre Reinforced Polymer Jackets Subjected to Compression." Advances in Civil Engineering 2019 (February 20, 2019): 1–11. http://dx.doi.org/10.1155/2019/1360620.
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The paper presents experimental and numerical investigations on the behaviour of rubberized concrete short columns confined with aramid fibre reinforced polymer (AFRP) subjected to compression. Additionally, the possibilities to substitute fine aggregate with crumb rubber granules, obtained from discarded worn tires, in structural concrete is also assessed. Because replacing traditional concrete aggregates by rubber particles leads to a significant loss in compressive strength, the authors highlight the use of AFRP confinement to partially or fully restore the compressive strength by applying a number of 1, 2, and 3 layers. Analytical models available for confined regular concrete are used to predict the peak stresses and the corresponding peak strains. Some analytical models give accurate results in terms of peak stress while others better approximate the ultimate strain. The full stress-strain curve of rubberized concrete and the experimentally obtained values for the material properties of AFRP are used as input data for the numerical modelling. A good agreement is found between the results obtained for the peak stress and corresponding axial strain from both the numerical simulations and the experimental investigations.
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Bakalarz, Michał Marcin, and Paweł Grzegorz Kossakowski. "Application of Transformed Cross-Section Method for Analytical Analysis of Laminated Veneer Lumber Beams Strengthened with Composite Materials." Fibers 11, no. 3 (2023): 24. http://dx.doi.org/10.3390/fib11030024.
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Due to the high cost of laboratory testing, many researchers are considering developing methods to predict the behavior of unreinforced and reinforced wood beams. This work aims to create either numerical or analytical models useful for extrapolating already conducted tests to other schemes/materials used as reinforcement. In the case of timber structures, due to the complexity of timber, this task is difficult. The first part of the article presents an analysis of the suitability of using a simplified mathematical model based on the equivalent cross-section method to describe the behavior of unreinforced and reinforced with carbon-fibre-reinforced polymer (CFRP) composite full-size laminated veneer lumber (LVL) beams. The theoretical results were compared with the results of conducted experimental tests. The scope of the analysis includes the estimation of modulus of rupture, bending stiffness, and determination of the neutral axis position. The equivalent cross-section method showed good agreement in determining the bending stiffness and neutral axis position of the strengthened sections. However, the suitability of using the equivalent cross-section method to estimate the load-carrying capacity of a cross-section reinforced with fiber composites still needs to be confirmed, which, according to the authors, is due to the differences between the assumed (linear) and actual (nonlinear) strain distribution in the compression zone. The second part uses the equivalent cross-section method to estimate the predicted bending stiffness of LVL beams strengthened with aramid-fibre-reinforced polymer (AFRP), glass-fibre-reinforced polymer (GFRP), and ultra-high modulus carbon-fibre-reinforced polymer (CFRP UHM) sheets. The proposed method can be used for preliminary evaluation of strengthening effectiveness of LVL beams.
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Vincent, Thomas, and Togay Ozbakkloglu. "Axial Compressive Behavior of High- and Ultra High-Strength Concrete-Filled AFRP Tubes." Advanced Materials Research 671-674 (March 2013): 626–31. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.626.
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Concrete-filled FRP tubes (CFFTs) have received significant research attention over the last two decades. However, the experimental studies on the behavior of CFFTs filled with high- and ultra high-strength concretes (HSC and UHSC) remain very limited. This paper presents the results of an experimental study on the compressive behavior of circular HSC- and UHSC-filled fiber reinforced polymer (FRP) tubes (HSCFFTs and UHSCFFTs). A total of 24 aramid fiber made CFFTs were tested under uniaxial compression to investigate the influences of concrete strength, amount of confinement and manufacturing method of FRP tubes. The influence of tube manufacturing method was investigated with specimens manufactured with either automated filament winding or manual wet lay-up techniques. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the manufacturing method of the FRP tubes significantly influence the compressive behavior of CFFTs.
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Dutu, Andreea, Hiroyasu Sakata, Yoshihiro Yamazaki, and Tomoki Shindo. "Retrofit solution for timber framed masonry system using aramid fiber reinforced polymers (AFRP)." IABSE Symposium Report 104, no. 22 (2015): 1–8. http://dx.doi.org/10.2749/222137815815774601.
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Vinod, Vawadra. "Pushover Analysis of a Reinforced Cement Concrete (RCC) Structure Incorporating Fibre-Reinforced Polymers to Address Vertical Irregularities." International Journal of Innovative Technology and Exploring Engineering (IJITEE) 14, no. 1 (2024): 14–19. https://doi.org/10.35940/ijitee.L1007.14011224.
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<strong>Abstract:</strong> India has had four of the world's most destructive earthquakes in the past ten years, and our country is often rocked by earthquakes of low to moderate intensity. Since many buildings were severely damaged or collapsed, it has sparked debate whether framed constructions are sufficiently sturdy to withstand significant vibrations. As a result, the strength or ability of existing reinforced concrete structures to withstand seismic loads can be evaluated. The performance level of earthquake-prone buildings is evaluated using a performance-based design. One seismic technique for assessing a building's performance level is push-over analysis. It is possible to determine whether damage occurs at the member or structure level using pushover analysis. The study employs pushover analysis by Applied Technology Council (ATC) – 4), a seismic assessment technique, to evaluate the ability of 20-story buildings in seismic Zone III (with hard soil characteristics) to resist earthquake-induced forces. The primary objective was to assess the performance of structures reinforced with different fiber-reinforced polymer (FRP) materials, including aramid, glass, and carbon fibers, known for their high flexibility and strength in seismically active regions. To determine the best fiber-reinforced polymer configuration, the study considers the following parameters: pushover curve, target displacement, story shear, time period, maximum story displacement, and story drift based on pushover analysis independently. Through the pushover analysis method, the research discovers that FRP wrapping can significantly improve the seismic performance of reinforced concrete buildings. The findings aim to improve building design practices by recommending fiber-reinforced polymer configurations for better earthquake resistance, ensuring that future constructions are better equipped to handle seismic activity.
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Alam, M. S., M. Arifuzzaman, M. K. Islam, A. F. Al-Fuhaid, and A. Al-Mamun. "Sustainable Solution for Deteriorated and Aged RCC Structures: A Review of Buildings, Bridges and Pavements." IOP Conference Series: Earth and Environmental Science 1026, no. 1 (2022): 012009. http://dx.doi.org/10.1088/1755-1315/1026/1/012009.
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Abstract Sustainability is an important topic worldwide. The sustainable design will reduce the consumption of energy, water, land and raw materials. This ought to be taken into account when designing new structures and strengthening and renovating of existing deteriorated structures. This paper deals with the sustainable solution for the strengthening and renovating of the deteriorated or impaired structures. This is usually done through the use of FRP strips / sheets or bars that is bonded outside the member. Many researches have been conducted on this technique to observe its behaviour and ultimate strength. The materials used in research are steel, glass fibre reinforced polymer (GFRP), carbon fibre reinforced polymer (CFRP), aramid fibre reinforced polymer (AFRP) sheets or bars. These were used as side bonding, U-jacketing and wrapping of the members. A significant improvement in strength was observed in the strengthened members. Accordingly, these techniques have been suggested as a sustainable solution. Based on the investigations, different countries propose different design codes and standards. Some of them provide reliable predictions, but more research is needed for an accurate and consistent predictive model.
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A. Aboul-Nour, Louay, Ragab S. Mahmoud, Mahmoud A. Khater, and Nesma M. Moselhy. "Reinforcement alternatives for beams under cyclic load." International Journal of Engineering & Technology 9, no. 2 (2020): 350. http://dx.doi.org/10.14419/ijet.v9i2.30350.
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The major cause of concrete structures deterioration is steel corrosion. Consequently, this situation has led researchers to study and test other reinforcement alternatives that are noncorrosive in nature. Rapidly emerging developments in the field of material technology has led to the development of fiber reinforced polymers (FRP). This research focuses on the flexural behavior of carbon, glass, aramid, and basalt (CFRP, GFRP, AFRP, and BFRP) fiber reinforced polymers bars as alternatives to the traditional steel reinforcement in concrete. The study involves a nonlinear numerical finite element analysis of a simply supported reinforced concrete beams subjected to cyclic loading, where the ANSYS program is utilized. The numerical model verification is executed on the experimental beams for ensuring the efficiency of ma-terial models, cyclic loading and various elements. Hysteresis curves are produced for each beam and analyzed, where loads, deflections, and cracks propagation are inspected and discussed. The results reveal that, the full replacement of traditional steel bars with CFRP bars gives the greatest increase in the ultimate load capacity by 38.5%. Also, other results are summarized in this paper.
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Deix, Karl, Christian Huber, and Josip Gogic. "Efficiency of Alternative Reinforcement Methods for Wooden Ceilings and Their Ecological Aspects." Materials 18, no. 9 (2025): 2032. https://doi.org/10.3390/ma18092032.
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In the case of load increases and the refurbishment of existing buildings, it is often necessary to carry out strengthening measures on existing timber beams. When timber concrete composite (TCC) ceilings cannot be used, it is possible to reinforce the undersides of the beams with structural steel or fiber composites (aramid or carbon-fiber-reinforced polymer). This work investigates how significant effects on the load-bearing and deformation behavior can be achieved with these materials in terms of construction practice. The article is intended to show structural engineers which reinforcement measures lead to which forces, deformations, etc., and how these are utilized. This should form the basis for the planning of reinforcement measures, as it is not clear from the beginning whether AFRP, CFRP, or steel is the most suitable material. For this purpose, a comparative parameter study was carried out under practical conditions and with a variable degree of reinforcement using the corresponding formulas. The internal forces in the timber and reinforcement cross-sections, the deflection behavior, and the failure loads at the strength and design levels were calculated. It was demonstrated that, particularly for steel and carbon-fiber-reinforced polymer (CFRP) reinforcements, significant increases in the ultimate load can be achieved and the often-important deformation behavior can be significantly improved. Especially the steel variant leads to high improvements in deflection and breaking load behavior, with the base material (wood) also being utilized more economically as a result. A comparative ecological study in the form of the global warming potential showed that reinforcement methods are also advantageous from the point of view of sustainability compared to renovations with timber concrete composite slabs or new concrete slabs.
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Vincent, Thomas, and Togay Ozbakkloglu. "The Effect of Confinement Method and Specimen End Condition on Behavior of FRP-Confined Concrete under Concentric Compression." Applied Mechanics and Materials 351-352 (August 2013): 650–53. http://dx.doi.org/10.4028/www.scientific.net/amm.351-352.650.
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This paper presents an experimental investigation on the influence of confinement method and specimen end condition on axial compressive behavior of fiber reinforced polymer (FRP)-confined concrete. A total of 12 aramid FRP (AFRP)-confined concrete specimens with circular cross-sections were tested. Half of these specimens were manufactured as concrete-filled FRP tubes (CFFTs) and the remaining half were FRP-wrapped concrete cylinders. The effect of specimen end condition was examined on both CFFTs and FRP-wrapped specimens. This parameter was selected to study the influence of loading the FRP jacket on the axial compressive behavior. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the performance of FRP-wrapped specimens is similar to that of CFFT specimens and the influence of specimen end condition is negligible.
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Vincent, Thomas, and Togay Ozbakkaloglu. "Lateral Strain-to-Axial Strain Model for Laterally Prestressed Concrete-Filled FRP Tubes." Key Engineering Materials 729 (February 2017): 134–38. http://dx.doi.org/10.4028/www.scientific.net/kem.729.134.
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Concrete-filled FRP tube (CFFT) columns have recently gained significant research attention, with a number of experimental studies identifying significant benefits of using high-strength concrete (HSC) to produce high-performance CFFT columns. A recent experimental investigation revealed that prestressing the fibers in the fiber reinforced polymer (FRP) confining shell leads to significant improvements in the axial compressive behavior of HSC-CFFTs. This paper reports the findings from an analytical investigation into the lateral strain-to-axial strain relationship for prestressed HSC-CFFTs. This understanding of the lateral strain-to-axial strain relationship is of particular importance for prestressed CFFTs due to the influence of the additional lateral prestrain. Initially a database that consists of 23 aramid FRP- (AFRP) confined HSC cylindrical specimens with lateral prestress of up to 7.3 MPa is presented. Based on close examination of the experimentally recorded data, an expression to predict the lateral strain-to-axial strain relationship for prestressed HSC-CFFTs is proposed. The comparison of the proposed model predictions with the experimental test results for specimens prepared with prestressed FRP tubes shows good agreement.
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Belarbi, A., M. Reda, P. Poudel, H. Tahsiri, M. Dawood, and B. Gencturk. "Prestressing Concrete with CFRP Composites for Sustainability and Corrosion-Free Applications." MATEC Web of Conferences 149 (2018): 01010. http://dx.doi.org/10.1051/matecconf/201814901010.
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Advancement in material science has enabled the engineers to enhance the strength and long-term behavior of concrete structures. The conventional approach is to use steel for prestressed bridge girders. Despite having good ductility and strength, beams prestressed with steel are susceptible to corrosion when subjected to environmental exposure. The corrosion of the prestressing steel reduces load carrying capacity of the prestressed member and result in catastrophic failures. In the last decades, more durable composite materials such as Aramid Fiber Reinforced Polymer (AFRP), Glass Fiber Reinforced Polymer (GFRP) and Carbon Fiber Reinforced Polymer (CFRP) have been implemented in concrete structures as a solution to this problem. Among these materials, CFRP stands out as a primary prestressing reinforcement, which has the potential to replace steel and provide corrosion free prestressed bridge girders. Despite its promise, prestressing CFRP has not frequently been used for bridge construction worldwide. The major contributing factor to the lack of advancement of this promising technology in the United States (U.S.) is the lack of comprehensive design specifications. Apart from a limited number of guides, manuals, and commentaries, there is currently no standard or comprehensive design guideline available to bridge engineers in the U.S. for the design of concrete structures prestressed with CFRP systems. The main goal is to develop design guidelines in AASHTO-LRFD format for concrete bridge girders with prestressing CFRP materials. The guidelines are intended to address the limitation in current AASHTO-LRFD Bridge Design Specifications which is applicable for prestressed bridge girders with steel strands. To accomplish this goal, some of the critical parameters that affect the design and long-term behavior of prestressed concrete bridge girders with prestressing CFRP systems are identified and included in the research work. This paper presents preliminary results of an experimental study that is part of a National Highway Co-operative Highway Research Program (NCHRP) project.
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Vincent, Thomas, and Togay Ozbakkaloglu. "Influence of Slenderness on Behavior of High-Strength Concrete-Filled FRP Tubes under Axial Compression." Applied Mechanics and Materials 501-504 (January 2014): 963–68. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.963.
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This paper presents an experimental investigation on the influence of specimen slenderness on axial compressive behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs). A total of 18 aramid FRP- (AFRP) confined high-strength concrete (HSC) specimens with circular cross-sections were tested. Specimens with height-to-diameter ratios of 1, 2, 3 and 5 were manufactured and tested, with all specimens maintaining a nominal diameter of 150 mm. The results indicate that specimens with an H/D of 1 exhibit significantly higher strength and strain enhancements compared to specimens with H/D ratios of 2 to 5. The influence of slenderness on specimens with H/D ratios between 2 and 5 was found to be significant in regards to axial strain enhancement, with a decrease observed as specimen slenderness increased. On the other hand, the influence of slenderness on axial strength enhancement of specimens with H/D ratios between 2 and 5 was found to be negligible.
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Vincent, Thomas. "Influence of Prestress on Axial Compressive Behavior of High-Strength Concrete-Filled FRP Tubes." Applied Mechanics and Materials 744-746 (March 2015): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.173.
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This paper presents an experimental investigation on the influence of prestress on axial compressive behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs). A total of 12 aramid FRP- (AFRP) confined high-strength concrete (HSC) specimens with circular cross-sections were tested under monotonic axial compression. All specimens were cylinders with 152 mm diameter and 305 mm height and their unconfined concrete strengths were approximately 100 to 110 MPa. The influence of FRP prestress was examined by applying 3 different levels of lateral prestress ranging from 4.29 to 7.27 MPa. In addition to the prestressed specimens, companion specimens with no applied prestress were manufactured and tested to establish reference values. Results of the experimental study indicate that the influence of prestress on compressive strength is significant, with an increase in ultimate strength observed in all prestressed specimens compared to that of non-prestressed specimens. On the other hand, the influence of prestress on axial strain was found to be minimal, with prestressed specimens displaying a slight decrease in ultimate strain, compared to their non-prestressed counterparts. The results also indicate that prestressing the AFRP shell prevents the sudden drop in strength, typically observed in FRP-confined HSC specimens, that initiates at the transition point which connects the first and second branches of the stress-strain curves.
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Vincent, Thomas, and Togay Ozbakkaloglu. "Predicting Strain Reduction Factor for Concrete-Filled FRP Tube Columns Incorporating Interface Gap and Prestress." Solid State Phenomena 263 (September 2017): 18–23. http://dx.doi.org/10.4028/www.scientific.net/ssp.263.18.
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This paper reports the findings from an analytical study into the influence of fiber reinforced polymer (FRP)-to-concrete interface gap and prestressed FRP tubes on strain reduction factor (kε) for concrete-filled FRP tube (CFFT) columns. A database that consists of a total of 45 aramid FRP- (AFRP) confined normal-and high-strength concrete (NSC and HSC) specimens with circular cross-sections is presented. All specimens were cylinders with a 152 mm diameter and 305 mm height, and their unconfined concrete strengths ranged from approximately 45 to 110 MPa. Analyses of the experimental databases that consisted of 22 specimens manufactured with FRP-to-concrete interface gap and a further 23 specimens prepared with lateral prestress is presented and discussed. Based on close examination of the hoop strain development on the FRP confining shell, expressions to predict strain reduction factors (kε) are proposed. The comparison of the proposed model predictions with the experimental test results of specimens prepared with an interface gap or prestressed FRP tubes shows good agreement.
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Zhu, Yan Mei, Shu Cheng Yuan, Min Hou, and Qing Yuan Wang. "Square Short Wood Columns Strengthened with FRP Sheets under Compressive Load." Applied Mechanics and Materials 256-259 (December 2012): 1008–11. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1008.
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This paper presents the experimental results of the wood columns externally strengthened with fiber reinforced polymer (FRP) subjected to axial compressive loading. In total, 14 square short wood columns were made, which were reinforced by FRP in two reinforcing arrangements. The main parameters studied in the test were (1) the strengthening materials, i.e. carbon FRP (CFRP), basalt FRP (BFRP) and aramid FRP (AFRP); (2) the reinforcing arrangements, i.e. the full wrapping of FRP and the partial reinforcing arrangement; (3) the layers of FRP sheets applied, i.e. one, two and three. The ultimate strength, load-axial displacements curves, load-strain relationships, and the failure modes of all the columns were presented. The test results show that both types of the reinforcing arrangements could increase the ultimate strength and stiffness of the columns tested greatly. The columns strengthened with two layers of FRP sheets gave higher load carrying capacities when compared to the columns strengthened with one or three layers of FRP sheets. The result confirms that the more layers of FRP sheets, the higher of load carrying capacity; however, the adverse results were shown when three layers of FRP sheets applied. Finally, the result also showed that the full wrapping reinforcing arrangement is more effective than the partial one in enhancing the stiffness.
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Fuhaid, Abdulrahman Al, Kazi Md Abu Sohel, and Md Arifuzzaman. "The Effect of Strengthening Methods on the Performance of Reinforced Concrete Columns against Vehicle Impact." Applied Sciences 12, no. 3 (2022): 1382. http://dx.doi.org/10.3390/app12031382.
Full textAbstract:
Columns at the ground floor and parking garages that could be hit by a car pose a significant risk to the structural stability of the building superstructures. Generally, these columns are not built to sustain the lateral impact force generated by car–column collision. In this study, the performance of axially loaded retrofitted reinforced concrete (RC) columns against car impact is evaluated using finite element (FE) simulation. The FE model of the RC column with axial load was validated with experimental results. For the car-crushing simulations, two SUV car models with a mass of about 2250 kg, which had been experimentally validated, were used to simulate the car–column collision. The results of the FE analysis revealed that once the impact speed exceeds 30 km/h, the horizontal impact force has a significant effect on the column joint at the foundation. The impact force increases linearly as the impact velocity of the car increases up to 20 km/h. When car impact velocities are more than 20 km/h, the generated impact force increases in power to the car-crashing velocity. Both types of cars have almost the same effect on the generation of impact force and the lateral displacement of the column. It is found that the generated impact forces are higher than the recommended design values of Eurocode 1. To protect the column from car impact damage, two types of column-strengthening systems were investigated. One form of strengthening system involves retrofitting the lower half of the column with an aramid fiber-reinforced polymer (AFRP) warp, while the other involves putting a reinforced concrete jacket of up to 1.3 m in the height of the column. Based on the comparative study, design recommendations are suggested to protect the RC column from accidental car-crashing damage.
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Junaedi, H., and T. A. Sebaey. "Carbon-Aramid Fiber/Epoxy Hybrid Composite Laminates with the Presence of Defect: An Experimental Study." Journal of Physics: Conference Series 2805, no. 1 (2024): 012008. http://dx.doi.org/10.1088/1742-6596/2805/1/012008.
Full textAbstract:
Abstract Carbon-Aramid fiber-reinforced epoxy has been used extensively in the aerospace and automobile industries. The combination of high-strength carbon fiber and the high toughness of aramid fiber is believed to be beneficial to the structural behavior of composites. In the current study, Aramid fiber was sandwiched between carbon fiber layers to maintain high strength and toughness simultaneously. The behavior of the laminate with the presence of an open hole and single-edge notch was investigated. For justification, the response of the hybrid laminate was compared with two other laminates, one is made totally from carbon fiber-reinforced epoxy (CFRP) and the other is made from aramid fiber-reinforced epoxy (AFRP). The effect of an open hole was assessed by a tension test, while the single-edge notch effect was evaluated by the flexural test. Tensile and flexural tests were also performed on the regular samples. As per the current results, the notch sensitivity of hybrid laminate was found to be less than that of CFRP laminate. The CFRP laminate failure type was dominated by delamination. AFRP composite laminate failure was dominated by fiber breakage and crack propagation through the matrix. The hybrid composite laminates were dominated by fiber breakage of the AFRP laminates and delamination of CFRP outer layers. The flexural modulus of hybrid laminate resulted in the greatest value, followed by CFRP and AFRP. The hybrid laminate’s fracture toughness is significantly higher than that of CFRP but lower than that of AFRP.
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Wen, Quan, Jintao Hu, and Zewei Yuan. "Sub-Fiber Scale Precision Dicing of Aramid Fiber-Reinforced Plastic Composites." Machines 10, no. 5 (2022): 334. http://dx.doi.org/10.3390/machines10050334.
Full textAbstract:
Aramid fiber-reinforced plastic (AFRP) composites are widely used in aerospace, rail transit, marine and military industries, due to their high specific strength, high impact resistance, fatigue resistance and excellent designable properties. In order to meet different application requirements, cutting processes need to be carried out, such as window opening, edge cutting and slit cutting. However, the characteristics of high tensile strength and toughness, low interlaminar strength, non-uniformity and anisotropy make AFRP composites a difficult-to-machine material. They are prone to produce rough cutting surfaces and cutting damages including burr, wire drawing, delamination, resin burn, material flanging, etc. To solve this problem, the ultra-thin diamond dicing blade was used for high-speed cutting of AFRP composites in sub-fiber scale in this research. The influence of process parameters on cutting force, cutting temperature, maximum spindle current, tool wear and cutting surface quality were investigated by establishing the cutting force model, L16(45) orthogonal experiment, single factor experiment, range analysis and variance analysis. The theoretical and experimental results show that cutting AFRP composites with ultra-thin diamond dicing blade can obtain smooth surfaces without common cutting damages. When the cutting speed is 91.11 m/s (spindle speed n = 30,000 r/min), the cutting depth is 0.2 mm and the feed speed is 5 mm/s, the surface roughness Ra can be as low as 32 nm, which realize the precision cutting of AFRP composites.
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KIM, CHEOL-WOONG, and DONG-JOON OH. "HIGH TECHNIQUE FOR T-PEEL STRENGTH ENHANCEMENT OF Al/AFRP HYBRID COMPOSITE." International Journal of Modern Physics B 20, no. 25n27 (2006): 4273–78. http://dx.doi.org/10.1142/s0217979206041215.
Full textAbstract:
The interlaminar peel strength of Al / AFRP (Aluminum alloy/Aramid Fiber Reinforced Plastic) hybrid composite is affected by the adhesive strength between the Al alloy layer and the aramid fiber layer. The study of the tensile strength and the T-peel strength of the Al / AFRP should be accomplished first. Therefore, this study focused on the effect of the resin mixture ratio as the Al / AFRP on the tensile strength and T-peel strength. In conclusions, the resin mixture ratio by equivalence ratio of 〈epoxy resin : curing agent〉 equal to 〈1:1〉 of Al / AFRP -I and the resin mixture ratio by equivalence ratio of 〈epoxy resin : curing agent : accelerator〉 equal to 〈1:1:0.2〉 of Al / AFRP -II showed the highest ultimate tensile strength. After the T-peel test, it is found that the T-peel strength of Al / AFRP -II is approximately 1.5 times higher than that of Al / AFRP -I. Reviewing the characteristics of the tensile and T-peel strengths, the resin mixture ratio 〈1:1:0.2〉 of Al / AFRP -II showed the highest tensile strength and T-peel strength.