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1
Subagia, I. D. G. Ary, and Yonjig Kim. "Tensile behavior of hybrid epoxy composite laminate containing carbon and basalt fibers." Science and Engineering of Composite Materials 21, no. 2 (March 1, 2014): 211–17. http://dx.doi.org/10.1515/secm-2013-0003.
Анотація:
AbstractThis paper investigated the effect of the incorporation of basalt fibers on the tensile properties of carbon fiber-reinforced epoxy laminates manufactured by vacuum-assisted resin transfer molding. The purpose of this research was to design a carbon-basalt/epoxy hybrid composite material that is of low cost in production, is lightweight, and has good strength and stiffness. The tensile strength and stiffness of the hybrid laminates demonstrated a steady, linear decrease with an increase in basalt fiber content, but the fracture strain gradually increased together with the increase in the basalt layer content. In this study, the incorporation of basalt fibers into the carbon fiber-reinforced polymer (CFRP) showed lower tensile strength than CFRP but has higher tensile strain. Furthermore, we found that the arrangement and enhancement of basalt fiber into the CFRP significantly influence the mechanical properties of interply hybrid composites.
2
Khan, Mohammad K. A., Harri Junaedi, Hassan Alshahrani, Ahmed Wagih, Gilles Lubineau, and Tamer A. Sebaey. "Enhanced Open-Hole Strength and Toughness of Sandwich Carbon-Kevlar Woven Composite Laminates." Polymers 15, no. 10 (May 11, 2023): 2276. http://dx.doi.org/10.3390/polym15102276.
Анотація:
Fiber-reinforced plastic composites are sensitive to holes, as they cut the main load-carrying member in the composite (fibers) and they induce out-of-plane stresses. In this study, we demonstrated notch sensitivity enhancement in a hybrid carbon/epoxy (CFRP) composite with a Kevlar core sandwich compared to monotonic CFRP and Kevlar composites. Open-hole tensile samples were cut using waterjet cutting at different width to diameter ratios and tested under tensile loading. We performed an open-hole tension (OHT) test to characterize the notch sensitivity of the composites via the comparison of the open-hole tensile strength and strain as well as the damage propagation (as monitored via CT scan). The results showed that hybrid laminate has lower notch sensitivity than CFRP and KFRP laminates because the strength reduction rate with hole size was lower. Moreover, this laminate showed no reduction in the failure strain by increasing the hole size up to 12 mm. At w/d = 6, the lowest drop in strength showed by the hybrid laminate was 65.4%, followed by the CFRP and KFRP laminates with 63.5% and 56.1%, respectively. For the specific strength, the hybrid laminate showed a 7% and 9% higher value as compared with CFRP and KFRP laminates, respectively. The enhancement in notch sensitivity was due to its progressive damage mode, which was initiated via delamination at the Kevlar–carbon interface, followed by matrix cracking and fiber breakage in the core layers. Finally, matrix cracking and fiber breakage occurred in the CFRP face sheet layers. The specific strength (normalized strength and strain to density) and strain were larger for the hybrid than the CFRP and KFRP laminates due to the lower density of Kevlar fibers and the progressive damage modes which delayed the final failure of the hybrid composite.
3
Ismail*, Mohd Fadzli, and Aidah Jumahat. "Impact Properties of Hybrid Fibre Reinforced Polymer Composite Laminates." International Journal of Innovative Technology and Exploring Engineering 9, no. 3 (January 30, 2020): 2763–66. http://dx.doi.org/10.35940/ijitee.c9206.019320.
Анотація:
The increasing demand for high-strength light-weight fibre reinforced polymer (FRP) composite materials has driven the researchers to further innovate and introduce hybrid reinforcement materials. The usage of hybrid FRP composite laminates in structural industries is still new and limited research has been reported in this area. Thus, this research is aimed to determine the impact properties of hybrid FRP composite laminate. The impact tests were carried out on three types of FRP composite laminates, i.e. Carbon, Glass and Hybrid, in order to determine the impact properties of the materials. The composite laminates were prepared using hot pressing method. It was found that the hybrid FRP composite laminate exhibited better impact properties with 13% higher specific energy absorption when compared to the neat carbon FRP composite laminate. The impact test on hybrid FRP composite laminate recorded higher peak force, deflection at peak force and energy absorbed values of 109%, 71% and 25% respectively, when compared to the neat CFRP composite laminate.
4
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.
Анотація:
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.
5
Liu, J. A., Z. Q. Dong, X. Y. Zhu, W. B. Sun, and Z. Q. Huang. "Flexural properties of lightweight carbon fiber/epoxy resin composite sandwiches with different fiber directions." Materials Research Express 9, no. 2 (February 1, 2022): 026506. http://dx.doi.org/10.1088/2053-1591/ac4dc5.
Анотація:
Abstract In this study, structurally efficient carbon fiber reinforced plastic (CFRP) sandwiches were developed via introducing pumice/Mg composite foams as new core material. The effects of the fiber direction (0°, 45°, 90°) on the mechanical properties of CFRP laminates and composite sandwiches were studied. Compared with 45°-CFRP and 90°-CFRP laminates, 0°-CFRP laminate exhibits outstanding flexural properties due to different failure modes. Correspondingly, the 0°-CFRP/PMSF composite sandwiches exhibit higher flexural strength than 45°-CFRP/PMSF and 90°-CFRP/PMSF composite sandwiches. The as-prepared composite sandwiches are lightweight and have higher specific strength than some traditional sandwiches. The different flexural behaviors of three types of sandwiches were observed to explain the failure mechanisms.
6
CASAPU, Maria, Michel ARRIGONI, and Ion FUIOREA FUIOREA. "Off-axis response and shear characterization of unidirectional ply-level hybrid carbon-fiber-reinforced polymer materials." INCAS BULLETIN 15, no. 3 (September 4, 2023): 31–46. http://dx.doi.org/10.13111/2066-8201.2023.15.3.3.
Анотація:
Composite materials, among them Carbon Fiber Reinforced Polymers (CFRP), have become a key material in structural applications for lightweight structures such as spacecraft and aircraft. CFRP can be found under various quality grades and their mechanical performances increase with their cost and quality grade. In order to limit the costs of the material without degrading technical performances, hybridization could be of interest. However, assessing the conservation of quality standards of hybridized CFRP is crucial. This paper investigates the off-axis mechanical response of ply-level hybrid carbon composites, with varying thickness and material quality. Two types of carbon fiber prepregs were combined in the same laminate using symmetric and asymmetric stacking sequences. Monotonic quasi-static off-axis tests were performed to evaluate the non-linear stress-strain behavior of the laminates, with Digital Image Correlation used to measure strain. The apparent elastic modulus and the in-plane shear modulus were evaluated from the tensile tests at three off-axis angles. The results indicate that the hybrid laminates exhibit higher failure stress levels compared to simple laminates, with an intermediate failure strain. Overall, this study provides insights into the off-axis mechanical behavior of ply-level hybrid carbon fiber composites, with potential applications in the design of composite structures.
7
Hu, Junfeng, Xutong Zhang, Zhou Chen, Wenkang Guo, Hang Li, and Xi Deng. "Experimental and Numerical Research on Open-Hole Strength and Damage Mechanism of Regularly Arrayed Short Fiber Reinforced Polymer Composite." Polymers 12, no. 7 (July 21, 2020): 1622. http://dx.doi.org/10.3390/polym12071622.
Анотація:
Laminates with unidirectionally arrayed chopped strands (UACS) are one of the advanced short fiber reinforced polymer composites (SFRP) with significant application prospect, which greatly improves mechanical properties compared to the traditional SFRP, meanwhile ensuring excellent flowability. In practice, composite laminate with an open hole is one of the typical connective components, and it is necessary to clarify the allowable load and damage tolerance performance of notched structures. In the present study, UACS laminates were fabricated using the continuous carbon fiber reinforced polymer (CFRP) prepreg, on which regularly arrayed bi-angled slits were introduced by a commercial numerical control cutter. The tensile strength and strain distribution around the open hole of the notched UACS laminate were experimentally investigated, while the damage progression near the open hole of the notched UACS laminate was analyzed by the finite element method (FEM). The tensile strength of the notched UACS laminate was measured at 298 MPa, which is about 60% of the strength of the unnotched UACS laminate. The simulation results match well with the experimental results, although there is a little overestimate on strength, by about 5% and 7%, for unnotched and notched UACS laminates, respectively. The final critical failure mode for the notched UACS laminate is mainly dominated by the delamination instead of the fiber breakage in the unnotched UACS laminate.
8
Yousuf, Aquib Bin, Sajjid Hasan Asif, Md Jalal Uddin Rumi, and Kamrul Hasan. "Progressive Failure Analysis of Carbon Fiber Reinforced Polymer Composite with a Circular Notch by Varying Fiber Orientation." IOP Conference Series: Materials Science and Engineering 1305, no. 1 (April 1, 2024): 012019. http://dx.doi.org/10.1088/1757-899x/1305/1/012019.
Анотація:
Abstract Progressive failure for Carbon Fiber Reinforced Polymer (CFRP) was computationally studied and analyzed using Hashin’s failure criteria. It was an interactive failure criterion having 4 separate modes of failure. 8 layers of plies were oriented at specific stacking sequences to create different laminates with dimensions being specified using the ASTM D5766 standard. A total of 7 types of laminate were modeled and simulated to predict the failure for each type under tensile loading. A circular notch was added in the center for the concentration of stress. The damage to the fiber and matrix propagated and failed the structure. Contour plot analyses showed failure progression of fibers and matrix around the circular notch. Results show that matrix failure most predominant and critical type of failure for most laminates. From the stress vs. strain curves, it was seen that the [0/90]4 cross-ply laminate showed the highest open-hole tensile strength.
9
Manomaisantiphap, Siwat, Vipin Kumar, Takao Okada, and Tomohiro Yokozeki. "Electrically conductive carbon fiber layers as lightning strike protection for non-conductive epoxy-based CFRP substrate." Journal of Composite Materials 54, no. 29 (June 24, 2020): 4547–55. http://dx.doi.org/10.1177/0021998320935946.
Анотація:
A large amount of electrically conductive fillers is needed to enhance a Carbon Fiber Reinforced Plastics (CFRP) electrical conductivity enough to withstand lightning strikes of peak currents. However, such large alien constituents hamper the inherent good mechanical properties of CFRP structures. In this work, a solution has been proposed to retain both desired properties in a CFRP laminate. Layer-wise hybrid laminate has been demonstrated as a solution for lightning strike protection of Carbon Fiber Reinforced Plastics (CFRP). Top few layers of a hybrid laminate are prepared using electrically conductive polymer-based resin (CF/C-POLY) to provide effective dissipation of lightning current while epoxy-based CFRP substrate (CF/Epoxy) provides the main structural strength. An insulating adhesive layer is used to bond CF/C-POLY and CF/Epoxy to prepare the laminate. The hybrid laminates were tested for their effectiveness against lightning strikes. Laminates were struck by modified lightning waveform of component A with peak current of -14 kA and -40 kA. The performance of the laminates against lightning strike were evaluated using high speed camera, high-speed and thermal camera. It is found that CF/C-POLY layer successfully defended the main structural component i.e. CF/Epoxy from lightning direct damage.
10
Zhong, Yu Cheng, and Sunil Chandrakant Joshi. "Diffusion Characteristics of Moisture in Polymer Composites under Different Hygrothermal Conditions." Advanced Materials Research 849 (November 2013): 69–74. http://dx.doi.org/10.4028/www.scientific.net/amr.849.69.
Анотація:
The diffusion of moisture in composite materials is a complex phenomenon. In this investigation, effects of temperature, laminate architecture and cyclic hygrothermal conditions on the moisture absorption behavior of carbon/epoxy laminates were explored. Both woven and unidirectional laminates were fabricated from carbon fiber reinforced epoxy prepreg materials (CFRP). Specimens were later immersed in water at different temperatures, including room temperature (RT), 60°C and 80°C, or exposed to cyclic hydrothermal conditions. Within the temperature range studied, the diffusion of moisture inside the CFRP laminates followed the Ficks law. Both the diffusivity and the saturation moisture contents of the conditioned laminates increased with temperature. Furthermore, no weight variation was observed when the specimens were stored in a freezer at-30°C. The architecture of the reinforcement fibers also exhibited significant influence on the diffusion behavior of moisture in the laminates. Under the same temperature, the diffusivity of moisture in woven laminates was higher than that in unidirectional laminates.
11
Xin, Yanming, Aiqin Tian, Liyuan Qu, Chao Su, Di Wang, Yue Xi, and Zongyu Chang. "Study on Tensile Performance of Double-Bolted Joints between Carbon Fiber Reinforced Polymer Plate and Aluminum Plate." Journal of Physics: Conference Series 2510, no. 1 (June 1, 2023): 012008. http://dx.doi.org/10.1088/1742-6596/2510/1/012008.
Анотація:
Abstract Carbon fiber reinforced polymer (CFRP) with high specific strength, specific modulus, and other outstanding properties, which could be used in aerospace, shipbuilding, and railway. The joint of carbon fiber composite material plate and metal material plate plays an important role in the overall performance of the structure. In this paper, a carbon fiber reinforced polymer (CFRP) progressive damage model is developed based on composite laminate theory and 3D Hashian theory. The model of the double bolt single lap joint shear connection is established for the CFRP plate and the finite element method is used to carry out the stress analysis and failure prediction of the lap structure. The effect on structural performance under tensile conditions was studied through the change of double bolt spacing. The results show that the decrease in bolt row spacing can lead to the interference effect between holes. In addition, the progressive damage of the composite plate is located near the center line of the bolt hole.
12
Bittrich, Lars, Axel Spickenheuer, José Humberto S. Almeida, Sascha Müller, Lothar Kroll, and Gert Heinrich. "Optimizing Variable-Axial Fiber-Reinforced Composite Laminates: The Direct Fiber Path Optimization Concept." Mathematical Problems in Engineering 2019 (February 19, 2019): 1–11. http://dx.doi.org/10.1155/2019/8260563.
Анотація:
The concept of aligning reinforcing fibers in arbitrary directions offers a new perception of exploiting the anisotropic characteristic of the carbon fiber-reinforced polymer (CFRP) composites. Complementary to the design concept of multiaxial composites, a laminate reinforced with curvilinear fibers is called variable-axial (also known as variable stiffness and variable angle tow). The Tailored Fiber Placement (TFP) technology is well capable of manufacturing textile preforming with a variable-axial fiber design by using adapted embroidery machines. This work introduces a novel concept for simulation and optimization of curvilinear fiber-reinforced composites, where the novelty relies on the local optimization of both fiber angle and intrinsic thickness build-up concomitantly. This framework is called Direct Fiber Path Optimization (DFPO). Besides the description of DFPO, its capabilities are exemplified by optimizing a CFRP open-hole tensile specimen. Key results show a clear improvement compared to the current often used approach of applying principal stress trajectories for a variable-axial reinforcement pattern.
13
Hassan, Shereen K. H., Mu`tasim S. Abdel-Jaber, and Maha Alqam. "Rehabilitation of Reinforced Concrete Deep Beams Using Carbon Fiber Reinforced Polymers (CFRP)." Modern Applied Science 12, no. 8 (July 28, 2018): 179. http://dx.doi.org/10.5539/mas.v12n8p179.
Анотація:
Reinforced concrete structures that incorporates deep beams are generally susceptible to deterioration due to weathering effects and sulphur attacks, under-design in the detailing of concrete cover and/or reinforcement, and construction errors. In lieu of demolishing and replacing these structures, rehabilitation and strengthening using carbon fiber composites becomes a cost-effective viable alternative. Recent advances in research and innovation have introduced concrete repair and strengthening systems that are primarily based on fiber reinforced polymer composites. These systems have offered engineers the opportunity to provide additional stability to the structural elements in question and to restore the damaged portions back to their original load carrying capacity. This paper investigates the effect of Carbon Fiber Reinforced Polymer (CFRP) composites in enhancing the flexural performance of damaged reinforced concrete deep beams. Two types of CFRP composites and epoxy were used in the experimental investigation carried out and as described by this paper: 1) high strength carbon fiber reinforced polymer (CFRP) plates, commercially known as MBrace Laminate, that are bonded using an epoxy resin specifically suited for the installation and used to strengthen existing structural members; and, 2) MBrace Fiber 230/4900, a 100% solids, low viscosity epoxy material that is used to encapsulate MBrace carbon, glass, and aramid fiber fabrics so that when it cures, it provides a high performance FRP sheet.Test samples were divided into four groups: A control group, and three rehabilitated test groups with CRFP fibers, where the main variable among them was the percent length of CRFP used along the bottom beam extreme surface between supports (i.e, for two of the groups reinforced with MBrace laminates), and the use of MBrace Fiber 230/4500 CRFP sheets on the 4th beam along its vertical sides as well as the bottom extreme face between supports. All beams had similar cross-sectional dimensions and reinforcement, and were designed to fail in flexure rather than shear. The results show that CFRP composites, both laminated and sheet type, have increased the load carrying capacity in comparison to the control specimen, where observations were recorded pertaining to the delayed formation of vertical flexural cracks at the section of maximum moment, and diagonal shear cracks at beam ends. The increase in the load carrying capacity varied among the three rehabilitated test group beams, with the 4th group showing the highest ultimate load carrying capacity when compared to the control specimen.
14
Tasdemir, Burcu, and Demirkan Coker. "Fatigue and static damage in curved woven fabric carbon fiber reinforced polymer laminates." Journal of Composite Materials 56, no. 11 (March 25, 2022): 1693–708. http://dx.doi.org/10.1177/00219983221078787.
Анотація:
Failure mechanisms of curved cross-ply laminates under static and fatigue loading have been studied extensively, but the examination of fabric laminates which are the most commonly used ply type in curved supports in airplane wing structures is lacking. In this study, unidirectional (UD) and fabric carbon fiber reinforced polymer (CFRP) laminates are examined to elucidate the failure initiation mechanisms of laminated composites under fatigue and static loading. The crucial point of the research is applying the analyses using fabric laminate with a currently used stacking sequence in commercial airplanes. In addition to the fabric laminate, UD laminate is also included in the research to compare the real complex stacking with the simplest stacking. In the experiments, it is observed that both static and fatigue failures initiate roughly at the maximum radial stress location (approximately 35% of the thickness from the inner radius). For UD laminates, there is no visible difference between the failure mechanisms under static and fatigue loadings. However, for fabric laminates, fatigue failure is observed to occur as a single major crack at the maximum radial stress location as in UD laminates, whereas static failure is observed to occur as multiple diffusive cracks at the maximum radial stress location. Additionally, cracks grow mostly as intralaminar cracks connected with regions of occasional interlaminar cracks.
15
Utami, Mala, Jonathan Ernest Sirait, Beny Budhi Septyanto, Aries Sudiarso, and I. Nengah Putra Apriyanto. "Laminar Composite Materials for Unmanned Aircraft Wings." Defense and Security Studies 3 (December 21, 2022): 106–12. http://dx.doi.org/10.37868/dss.v3.id211.
Анотація:
Unmanned Aerial Vehicles (UAVs) have high popularity, especially in the military field, but are now also being applied to the private and public sectors. One of the UAV components that require high material technology is the wing. The latest material technology developed as a material for unmanned aircraft wings is a composite material that has high strength and lightweight. This research aims to identify composite materials that can be used for unmanned aircraft wing structures. The method used in this research is a qualitative method with a literature study approach. The results of this theoretical study show that some of the latest composite materials that have been developed into materials for unmanned aircraft wings are Laminar Composites with a sandwich structure. Laminar and sandwich composites consist of various constituent materials such as Balsa wood fiber-glass and polyester resin, microparticles, Carbon Fibre Reinforced Polymer, polymer matrix composites reinforced with continuous fibers, Polymer matrix composites, E-glass/Epoxy, Kevlar/Epoxy, Carbon/Epoxy, woven fabrics, acrylonitrile butadiene styrene-carbon (ABS) laminated with carbon fiber reinforced polymer (CFRP) and uniaxial prepreg fabrics. Laminar and sandwich composite materials are a reference for developing unmanned aircraft wing structures that have resistant strength and lightweight.
16
Zhou, Xiaoqiang, Qingquan You, Yuan Gao, Fenfei Hua, Wanbiao Fu, Qingyang Huang, and Yuanfang Wang. "Buckling Analysis on Resin Base Laminated Plate Reinforced with Uniform and Functional Gradient Distribution of Carbon Fiber in Thermal Environment." Polymers 15, no. 9 (April 27, 2023): 2086. http://dx.doi.org/10.3390/polym15092086.
Анотація:
The present paper aims to investigate the buckling load of functionally graded carbon-fiber-reinforced polymer (FG-CFRP) composite laminated plates under in-plane loads in a thermal environment. The effective material properties of the CFRP composite are calculated by the Mori–Tanaka homogenization method. The theoretical formulations are based on classical laminate plate theory (CLPT) and the von Kármán equations for large deflections. The governing equations are derived based on the principle of virtual work and then solved through the Navier solution. Results are obtained for the critical buckling load and temperature effect of a simply supported plate subjected to in-plane loading. A detailed numerical study is conducted to provide important insights into the effects of the functionally graded carbon fiber (CF) distribution pattern and volume fraction, total number of layers, temperature, geometrical dimension and lamination angle on the buckling load of functionally carbon-fiber-reinforced composite plates. Finally, the validation is compared with the Reddy and finite element analyses, which show consistency with each other.
17
Zheng, Hua Sheng, Si Rong Zhu, Zhuo Qiu Li, and Jing Li. "Sensitivity of the Carbon Fiber Interface in Epoxy." Applied Mechanics and Materials 69 (July 2011): 79–82. http://dx.doi.org/10.4028/www.scientific.net/amm.69.79.
Анотація:
In order to improve the gauge factor of polymer-matrix carbon fiber reinforced composites (CFRP) for strain sensing, the carbon fiber sensitive interface was constructed in epoxy by effectively overlapping the CFRP laminates in local area. The strain sensitivities of the carbon fiber interface were proved by the cyclic tension test on the base specimens covered by the carbon fiber composites with the sensitive interface, and their much bigger gauge factors were revealed by the comparison with the polymer-matrix continuous carbon fiber composite. The sensitivity of the carbon fiber interface is originated from the change of the interfacial points due to the interfacial stress.
18
Islam, Mohammad Rakibul, Md Nazim Uddin, Wyatt Taylor, Ryan Warren, and Kuang-Ting Hsiao. "Enhancing the Longitudinal Compressive Strength of Freeform 3D-Printed Continuous Carbon Fiber-Reinforced Polymer Composite Laminate Using Magnetic Compaction Force and Nanofiber Z-Threads." Materials 17, no. 7 (March 30, 2024): 1589. http://dx.doi.org/10.3390/ma17071589.
Анотація:
Low fiber-direction compressive strength is a well-recognized weakness of carbon fiber-reinforced polymer (CFRP) composites. When a CFRP is produced using 3D printing, the compressive strength is further degraded. To solve this issue, in this paper, a novel magnetic compaction force-assisted additive manufacturing (MCFA-AM) method is used to print CFRP laminates reinforced with carbon nanofiber (CNF) z-threads (i.e., ZT-CFRP). MCFA-AM utilizes a magnetic force to simultaneously levitate, deposit, and compact fast-curing CFRP prepregs in free space and quickly solidifies the CFRP laminate part without any mold nor supporting substrate plate; it effectively reduces the voids. The longitudinal compressive test was performed on five different sample types. ZT-CFRP/MCFA-AM samples were printed under two different magnetic compaction rolling pressures, i.e., 0.5 bar and 0.78 bar. Compared with the longitudinal compressive strength of a typical CFRP manufactured by the traditional out-of-autoclave–vacuum-bag-only (OOA-VBO) molding process at the steady-state pressure of 0.82 bar, the ZT-CFRP/MCFA-AM samples showed either comparable results (by −1.00% difference) or enhanced results (+7.42% improvement) by using 0.5 bar or 0.78 bar magnetic rolling pressures, respectively.
19
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 (January 3, 2021): 384. http://dx.doi.org/10.3390/app11010384.
Анотація:
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.
20
Chen, Cong, Hua-Ping Wang, Jie Ma, and Maihemuti Wusiman. "Dynamic Feature Identification of Carbon-Fiber-Reinforced Polymer Laminates Based on Fiber Bragg Grating Sensing Technology." Buildings 13, no. 9 (September 8, 2023): 2292. http://dx.doi.org/10.3390/buildings13092292.
Анотація:
Carbon-fiber-reinforced polymer (CFRP) composites have many advantages, and have been widely used in aerospace structures, buildings, bridges, etc. The analysis of dynamic response characteristics of CFRP composite structures is of great significance for promoting the development of smart composite structures. For this reason, vibration experiments of CFRP laminates with surface-attached fiber Bragg grating (FBG) sensors under various dynamic loading conditions were carried out. Time- and frequency-domain analyses were conducted on the FBG testing signals to check the dynamic characteristics of the CFRP structure and the sensing performance of the installed sensors. The results show that the FBG sensors attached to the surface of the CFRP laminates can accurately measure the dynamic response and determine the excited position of the CFRP laminates, as well as invert the strain distribution of the CFRP laminates through the FBG sensors at different positions. By performing Fourier transform, short-time Fourier transform, and frequency domain decomposition (FDD) on the FBG sensing signals, the time–frequency information and the first eight modal frequencies of the excited CFRP structure can be obtained. The modal frequencies obtained by different excitation types are similar, which can be used for structural damage identification. The research in this paper clarifies the effectiveness and accuracy of FBG sensors in sensing the dynamic characteristics of CFRP structures, which can be used for performance evaluation of CFRP structures and will effectively promote the design and development of intelligent composite material structures.
21
Artner, Gerald, Philipp K. Gentner, Johann Nicolics, and Christoph F. Mecklenbräuker. "Carbon Fiber Reinforced Polymer with Shredded Fibers: Quasi-Isotropic Material Properties and Antenna Performance." International Journal of Antennas and Propagation 2017 (2017): 1–11. http://dx.doi.org/10.1155/2017/6152651.
Анотація:
A carbon fiber reinforced polymer (CFRP) laminate, with the top layer consisting of shredded fibers, is proposed and manufactured. The shredded fibers are aligned randomly on the surface to achieve a more isotropic conductivity, as is desired in antenna applications. Moreover, fiber shreds can be recycled from carbon fiber composites. Conductivity, permittivity, and permeability are obtained with the Nicolson-Ross-Weir method from material samples measured inside rectangular waveguides in the frequency range of 4 to 6 GHz. The decrease in material anisotropy results in negligible influence on antennas. This is shown by measuring the proposed CFRP as ground plane material for both a narrowband wire monopole antenna for 5.9 GHz and an ultrawideband conical monopole antenna for 1–10 GHz. For comparison, all measurements are repeated with a twill-weave CFRP.
22
Filik, Kamil, Grzegorz Karnas, Grzegorz Masłowski, Mariusz Oleksy, Rafał Oliwa, and Katarzyna Bulanda. "Testing of Conductive Carbon Fiber Reinforced Polymer Composites Using Current Impulses Simulating Lightning Effects." Energies 14, no. 23 (November 25, 2021): 7899. http://dx.doi.org/10.3390/en14237899.
Анотація:
Carbon fiber reinforced polymer (CFRP) composites are lightweight and an increasingly used material with good mechanical properties. In the aviation industry, they are also required to have specific electrical properties that guarantee resistance to the direct and indirect lightning effects. The paper is focused on the description of a test stand and development of a method used to determine the electrical characteristics of conductive CFRP laminate samples with the use of high current impulses of lightning nature. Samples of three laminates (square format with side 30 × 30 cm) with a different composition were tested on the constructed stand, confirming the possibility of characterizing this type of laminate sample in terms of electrical conductivity and resistance to the effects of lightning current. It was possible to observe the impulse current flow (with a peak value up to 15 kA and a rise time above 6 µs) from the high voltage electrode placed in the center of the sample in all directions towards the edge. The optical fiber measuring system was used to record the voltage and current time waveforms. The energy stored in the impulse current generator was sufficient to simulate the mechanical damage, such as burnout and delamination, that accompanies the direct lightning strike to structural elements made of CFRP. The influence of the matrix composition used for laminate fabrication on the test results describing the electrical properties of the tested CFRP samples was noted. The experimental setup allows the testing of specimens with a maximum width and length of 50 × 50 cm and any thickness with a peak current of up to 50 kA.
23
Banat, Dominik. "Load-carrying capacity of the GFRP and CFRP composite beams subjected to three-point bending test – numerical investigations." Mechanics and Mechanical Engineering 23, no. 1 (July 10, 2019): 277–86. http://dx.doi.org/10.2478/mme-2019-0037.
Анотація:
Abstract The subject of this article is the finite element method (FEM) simulation of the multi-layered rectangular composite beam subjected to three-point bending test. The study is focused on the composite beams made of glass or carbon fibre-reinforced laminates (glass fibre-reinforced polymer [GFRP] and carbon fibre-reinforced polymer [CFRP]) for which different laminate stacking were addressed. Three beam geometries with various length-to-thickness ratios included short beam shear (SBS) test, provided the beam is short relative to its thickness, which maximised the induced shear stresses. Simulation included the application of Tsai–Hill, Hoffman, Tsai–Wu, Hashin and Puck failure criteria to perform the composite beam failure analysis wherein the matrix and fibre failure were considered separately. Numerical failure studies also aimed to verify the beam failure modes and the participation of stress tensor elements in material failure.
24
Li, Fangyuan, Wenhao Li, Shaohui Lu, and Yin Shen. "Development of a Prestressing CFRP Laminate Anchorage System and Bridge Strengthening Application." Advances in Materials Science and Engineering 2019 (September 30, 2019): 1–9. http://dx.doi.org/10.1155/2019/3503898.
Анотація:
For prestressed carbon fiber reinforced polymer (CFRP) tendon anchorage systems to become well established and used on a large scale, practical requirements for structure strengthening may be met by performing a relatively easy anchorage technique using prestressing CFRP laminates. From testing performed on a clip-type CFRP laminate anchorage system developed in our research group, it was revealed that this system could achieve the anchorage efficiency and the relaxation met the requirement of specification. Furthermore, the relevant indices of the anchorage system met the prestressed system standards. A test on the load-carrying capacity of a full-scale model beam demonstrated that the load-carrying capacity of the beam increased by more than 60% after it was strengthened with the anchorage system. The prestressing CFRP laminates and the bridge structure deformed and bore stress as a composite and exhibited excellent operating performance when working together.
25
Xu, Wei, Yunfeng Lu, Ruihu Zhu, Maciej Radzieński, Maosen Cao, and Wiesław Ostachowicz. "Shear Strain Singularity-Inspired Identification of Initial Delamination in CFRP Laminates: Multiscale Modulation Filter for Extraction of Damage Features." Polymers 14, no. 11 (June 6, 2022): 2305. http://dx.doi.org/10.3390/polym14112305.
Анотація:
Identification of initial delamination is crucial to ensure the safety of the fiber-reinforced laminated composite structures. Amongst the identification approaches based on mode shapes, the concept of multiscale shear-strain gradient (MSG) has an explicit physical sense of characterizing delamination-induced singularity of shear strains; moreover, it is robust against noise interference owing to the merits of multiscale analysis. However, the capacity of the MSG for identifying initial delamination is insufficient because the delamination-induced singularity peak can be largely obscured by the global component of the MSG. Addressing this problem, this study proposes an enhanced approach for identifying initial delamination in fiber-reinforced composite laminates. In particular, the multiscale modulation filter (MMF) is proposed to modulate the MSG with the aim of focusing on damage features, by which a new concept of enhanced MSG (EMSG) is formulated to extract damage features. By taking advantage of the MMF with the optimal frequency translation parameters, the EMSG is concentrated in a narrow wavenumber band, which is dominated by the damage-induced singularity peak. As a consequence, the delamination-induced singularity peak in the EMSG can be isolated from the global component. The capacity of the approach for identifying initial delamination is experimentally validated on a carbon fiber reinforced polymer (CFRP) laminate, whose mode shapes are acquired via non-contact laser measurement. The experimental results reveal that the EMSG-based approach is capable of graphically characterizing the presence, location, and size of initial delamination in CFRP laminates.
26
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.
Анотація:
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.
27
Matalgah, Khaled, Pruthul Kokkada Ravindranath, Daniel Pulipati, and Trevor J. Fleck. "Automated Quantification of Interlaminar Delaminations in Carbon-Fiber-Reinforced Polymers via High-Resolution Ultrasonic Testing." Polymers 15, no. 24 (December 13, 2023): 4691. http://dx.doi.org/10.3390/polym15244691.
Анотація:
This article presents a method of ultrasonic testing (UT) that detects and quantifies interlaminar delaminations in CFRP composites with high resolution in terms of both spatial resolution in the planar dimension and depth into the laminate. Unidirectional and woven CFRP laminates were fabricated for this study, with a PTFE film inserted at various depths throughout the laminate to act as intentional crack initiation sites. All samples were mechanically tested via a three-point, end-notched flexure (ENF) test, followed by a quantification of the extent of the induced interlaminar delaminations using UT and X-ray computed tomography (CT). UT analysis for unidirectional CFRP samples was able to show a clear contrast between the delaminated area and the non-delaminated area. UT analysis of the woven CFRP samples yielded comparable results but required finer tuning of analysis parameters due to the interlocking woven fabric. CT results revealed a significant contrast between the crack and composite; thus, fine geometrical features of the crack front could be observed. UT and CT measurements were then compared, revealing an average difference of 1.09% in the delamination area, with UT overestimating as compared to CT. A UT depth study was also performed to automatically locate the interlaminar delamination at different depths throughout the components, with the delamination being predicted within one lamina interface for all samples. These results demonstrate UT’s ability to accurately detect and quantify the extent and location of interlaminar delaminations due to bending.
28
Dou, Yukuan, Jinguang Zhang, Xianglong Wen, Hui Cheng, and Haixin Liu. "Free Vibration Characteristics of CFRP Laminate with One-Dimensional Periodic Structures." Polymers 15, no. 5 (February 23, 2023): 1118. http://dx.doi.org/10.3390/polym15051118.
Анотація:
This paper proposes an approach of stacking prepreg periodically for carbon fiber-reinforced polymer composites (CFRP) laminate. This paper will discuss the natural frequency, modal damping, and vibration characteristics of CFRP laminate with one-dimensional periodic structures. The damping ratio of CFRP laminate is calculated using the semi-analytical method which combines modal strain energy with the finite element method. The finite element method is used to calculate the natural frequency and bending stiffness which are verified with experiments. The numerical results of the damping ratio, natural frequency, and bending stiffness are in good agreement with the experiment results. Finally, the bending vibration characteristics of CFRP laminate with one-dimensional periodic structures and traditional CFRP laminate are investigated with experiments. The finding confirmed that the CFRP laminate with one-dimensional periodic structures exists band gaps. This study provides theoretical support for the promotion and application of CFRP laminate in the field of vibration and noise.
29
Knápek, Tomáš, Štěpánka Dvořáčková, and Artur Knap. "Wear Study of Coated Mills during Circumferential Milling of Carbon Fiber-Reinforced Composites and Their Influence on the Sustainable Quality of the Machined Surface." Coatings 12, no. 10 (September 21, 2022): 1379. http://dx.doi.org/10.3390/coatings12101379.
Анотація:
Composite materials made of fiber-reinforced plastic laminates are highly susceptible to surface damage caused by wear during contour milling, especially with inappropriate tool and cutting material properties. Improper choice of tools and cutting conditions lead to delamination between applied layers, thermal damage of materials in the polymer matrix, and reduction of the edge quality of cutting tools. The study was devoted to circumferential milling of twill-bonded CFRP (carbon-fiber-reinforced polymer) sheets with a focus on cutting forces and tool flank face wear, including their effect on the machined surface structure, roughness, and topography of the laminate. The main objective of the study is to investigate the feasibility of applying conventional coated tools, which are not primarily designed for milling CFRP, in comparison to a dedicated DLC (diamond-like carbon) coated tool, due to economic and distribution availability and the possibility of providing suitable cutting conditions during milling. The study provides results confirming the possibility of using conventional tools for machining CFRP and provides relevant experimental results that can be implemented for optimal tool selection, tool life criteria, cutting conditions, and machining strategies including low energy consumption. The best values of the investigated parameters were obtained when using the ECSSF (instrument designation) tool with DLC coating.
30
R. Koloor, S. S., A. Karimzadeh, M. R. Abdullah, M. Petrů, N. Yidris, S. M. Sapuan, and M. N. Tamin. "Linear-Nonlinear Stiffness Responses of Carbon Fiber-Reinforced Polymer Composite Materials and Structures: A Numerical Study." Polymers 13, no. 3 (January 22, 2021): 344. http://dx.doi.org/10.3390/polym13030344.
Анотація:
The stiffness response or load-deformation/displacement behavior is the most important mechanical behavior that frequently being utilized for validation of the mathematical-physical models representing the mechanical behavior of solid objects in numerical method, compared to actual experimental data. This numerical study aims to investigate the linear-nonlinear stiffness behavior of carbon fiber-reinforced polymer (CFRP) composites at material and structural levels, and its dependency to the sets of individual/group elastic and damage model parameters. In this regard, a validated constitutive damage model, elastic-damage properties as reference data, and simulation process, that account for elastic, yielding, and damage evolution, are considered in the finite element model development process. The linear-nonlinear stiffness responses of four cases are examined, including a unidirectional CFRP composite laminate (material level) under tensile load, and also three multidirectional composite structures under flexural loads. The result indicated a direct dependency of the stiffness response at the material level to the elastic properties. However, the stiffness behavior of the composite structures depends both on the structural configuration, geometry, lay-ups as well as the mechanical properties of the CFRP composite. The value of maximum reaction force and displacement of the composite structures, as well as the nonlinear response of the structures are highly dependent not only to the mechanical properties, but also to the geometry and the configuration of the structures.
31
Rai, Gopal L. "Advanced Active Prestressed CFRP in RCC Structures." Advanced Materials Research 1129 (November 2015): 290–97. http://dx.doi.org/10.4028/www.scientific.net/amr.1129.290.
Анотація:
. The need for rehabilitation of reinforced concrete structures is rapidly increasing. Fibre reinforced polymer (FRP) composite materials for concrete structures have high strength-to-weight ratios that can provide high prestressing forces while adding minimal additional weight to a structure. They also have good fatigue properties and exhibit low relaxation losses, both of which can increase the service lives and the load carrying capacities of reinforced concrete structures. Carbon fiber reinforced polymer (CFRP) composite system is integrated system based on carbon fibres and epoxy resins. By prestressing the CFRP laminates, the material is used more efficiently as a part of its tensile capacity is utilised and it contributes to the load bearing capacity under both service and ultimate load condition. This is an ideal technique as it combines the advantage of using noncorrosive and lightweight advanced composite material in the form of FRP laminates with high efficiency offered by external prestressing. An innovative mechanical anchorage system was developed to prestress the FRP laminates directly by jacking and reacting against the RCC structure.This paper describes the use of Prestressed CFRP laminates for strengthening of RCC structures including practical applications on slabs and bridges. Also it elucidates the post strengthening testing carried out for the validation of this technique.
32
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.
Анотація:
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.
33
Al-Salmani, Ismael, Zaid Al-Azawi, and Jamal Al-Esawi. "Strengthening of Composite Castellated Beams Web with Corrugated Carbon Fiber Reinforced Polymer Struts." Key Engineering Materials 870 (October 2020): 49–60. http://dx.doi.org/10.4028/www.scientific.net/kem.870.49.
Анотація:
A total of seven simply supported composite specimens are tested under concentrated load at the mid-span of the beam to investigate the strength of specimens to resist the applied load if web buckling take place. A novel technique of using a corrugated CFRP struts to strengthen the web of the steel girder is presented in this study. This technique provides two layers of CFRP laminate which are from biaxial fabrics to provide a knitted material that can undergo the complex state of stress in the web. The studied specimens are divided into two groups in addition to the control specimen having the same length. There are three specimens in each group, these specimens have different castellation ratios of (33.3%, 43.3% and 54.3%), the first group is identical to the second one except that the second group was strengthened with the proposed CFRP corrugated struts while the first one kept unstrengthen as a reference. Composite beams have a vertical stiffener at the action area above the supports. The reference group showed decrease in deflection of (11.11, 20 and 26.67) % for (33.3, 43.3 and 54.3) castellation ratio while strengthened girders record (13.75, 6.11 and 13.93) % for the same opening depths, compared to the control specimen. In addition, CFRP struts decrease the web buckling from (1.6, 2.9 and 83.33) to (0.8, 0.4 and 0.3) mm for beams with castellation ratio of (33.3, 43.3 and 54.3) respectively.
34
Zhao, Weina, Hongwei Song, Chenguang Huang, and Yihui Huang. "Modeling the Failure Behavior of CFRP Laminates Subjected to Combined Thermal and Mechanical Loadings." International Journal of Applied Mechanics 09, no. 03 (April 2017): 1750033. http://dx.doi.org/10.1142/s1758825117500338.
Анотація:
This paper proposes a theoretical approach to predict the failure behavior of laminated carbon fiber reinforced polymer (CFRP) under combined thermal and mechanical loadings. Two types of CFRP Laminates, i.e., CCF300/BA9916 and T700/BA9916, are investigated, and TGA tests in both nitrogen and oxidation environments at different heating rates are carried out to obtain the thermal decomposition kinetic parameters of polymer matrix and carbon fiber. Based on the thermal decomposition behavior and a multi-level structure model, the thermal physical properties, mechanical properties and thermal deformations of the laminated composites at high temperatures are obtained. Then substituting thermally degraded properties into constitutive equations of composite materials as macroscopic defects, the damage mode and failure strength of the laminated composite under thermo-mechanical loadings is obtained. Predicted elastic properties and failure strength are compared with experimental results as well as previous models. Effects of heating rates and heating environments through rigorous physical model are considered in the present work. It is found that the heating rate significantly affects the thermal and mechanical properties, the higher the heating rate, the less degraded are the thermo-mechanical properties and failure strength at a given temperature. Young’s modulus and failure strength of T700/BA9916 are higher than those of CCF300/BA9916 at high temperatures, due to the higher volume fraction of carbon fibers, which are less weakened in thermal environment.
35
Khene, Ahmed, Habib Abdelhak Mesbah, and Nasr-Eddine Chikh. "Numerical Analysis of the Flexural Response of Rc Beams Strengthened with NSM-CFRP." Civil and Environmental Engineering Reports 28, no. 3 (September 1, 2018): 90–102. http://dx.doi.org/10.2478/ceer-2018-0037.
Анотація:
Abstract In this study, we have chosen to use a new technique of reinforcement with composite materials, namely the near surface mounted technique (NSM). The NSM technique consists in inserting strips of carbon fiber reinforced polymer (CFRP) laminate into slits made beforehand at the level of the concrete coating of the elements to be reinforced. A numerical investigation was conducted on rectangular reinforced concrete beams reinforced with NSM-CFRP using the ATENA finite element code. A parametric study was also carried out in this research. The numerical results were compared with the experimental results of the beams tested by other researchers with the same reinforcement configurations. Overall, numerical behavior laws are rather well-suited to those obtained experimentally and the parametric study has also yielded interesting results.
36
Ren, Mingfa, Fei Weng, Jing Sun, Ke Tang, Lina Feng, and Rong Chen. "Influence of Weakening Groove on Cutting Results of Composites Subjected to Shaped Charge Jet." Shock and Vibration 2021 (March 10, 2021): 1–12. http://dx.doi.org/10.1155/2021/5528574.
Анотація:
Carbon-fiber-reinforced polymer (CFRP) has been widely used in aerospace structures for its high strength to weight ratio and high stiffness to weight ratio. However, current pyrotechnic separation devices are mainly made of metal materials, the cutting research on CFRP composites is limited, and the effect of weakening groove on cutting results of composites is unclear under the action of shaped charge jet. In this paper, there firstly established a three-dimensional model of explosive cutting of CFRP composites by nonlinear finite element analysis (FEA), and based on the separation time, delamination, and kinetic energy of the laminate, the influence of weakening grooves on cutting results to the laminate is discussed. The results show that, in contrast to laminates with weakening grooves, laminates without weakening grooves increase the delamination of laminates. At the same time, here, we carried out the explosive cutting test on CFRP composites to verify the rationality of the simulation model. In addition, in order to obtain a better model under the action of shaped charge jet, we optimized the width and height of weakening groove by simulation calculation. Therefore, it proves that this study can guide the application of CFRP composites subjected to shaped charge jet in aerospace separation engineering.
37
An, Ziqian, Xiaoquan Cheng, Dafang Zhao, Yihao Ma, Xin Guo, and Yujia Cheng. "Tensile and Compressive Properties of Woven Fabric Carbon Fiber-Reinforced Polymer Laminates Containing Three-Dimensional Microvascular Channels." Polymers 16, no. 5 (February 29, 2024): 665. http://dx.doi.org/10.3390/polym16050665.
Анотація:
Microvascular self-healing composite materials have significant potential for application and their mechanical properties need in-depth investigation. In this paper, the tensile and compressive properties of woven fabric carbon fiber-reinforced polymer (CFRP) laminates containing three-dimensional microvascular channels were investigated experimentally. Several detailed finite element (FE) models were established to simulate the mechanical behavior of the laminate and the effectiveness of different models was examined. The damage propagation process of the microvascular laminates and the influence of microvascular parameters were studied by the validated models. The results show that microvascular channels arranged along the thickness direction (z-direction) of the laminates are critical locations under the loads. The channels have minimal effect on the stiffness of the laminates but cause a certain reduction in strength, which varies approximately linearly with the z-direction channel diameter within its common design range of 0.1~1 mm. It is necessary to consider the resin-rich region formed around microvascular channels in the warp and weft fiber yarns of the woven fabric composite when establishing the FE model. The layers in the model should be assigned with equivalent unidirectional ply material in order to calculate the mechanical properties of laminates correctly.
38
Khan, Safdar Ali, Seyed Saeid Rahimian Koloor, Wong King Jye, Geralt Siebert, and Mohd Nasir Tamin. "A Fatigue Model to Predict Interlaminar Damage of FRP Composite Laminates Subjected to Mode I Loads." Polymers 15, no. 3 (January 19, 2023): 527. http://dx.doi.org/10.3390/polym15030527.
Анотація:
In fiber-reinforced polymer (FRP) composite laminate structures operating under fluctuating stresses, interface delamination is seen as one of the significant damage mechanisms. The constant degradation of their relatively low interlaminar strength and stiffness are the primary reasons for delamination. This study develops an interlaminar fatigue damage model to quantify the mechanics of the damage process and address the reliability of composite structures. The model considers the failure process in two stages: (1) damage due to degradation of interlaminar properties, and (2) damage due to dissipation of fracture energy as the damage evolution. The model is examined for a case study of mode I fatigue loading of a carbon-fiber-reinforced polymer (CFRP) composite laminate beam. The results show that the interlaminar normal stress is confined to the crack front region, with tensile stress peaks at 70% of the interlaminar strength. Furthermore, a stable interface crack growth is predicted initially, followed by a sudden crack “jump” at 14,000 cycles. The simulation results are compared with the experimental results, with very good agreement, showing a successful validation.
39
Malekinejad, Hossein, Farin Ramezani, Ricardo J. C. Carbas, Eduardo A. S. Marques, and Lucas F. M. da Silva. "Study of CFRP Laminate Gradually Modified throughout the Thickness Using Thin Ply under Transvers Tensile Loading." Materials 17, no. 10 (May 16, 2024): 2388. http://dx.doi.org/10.3390/ma17102388.
Анотація:
The use of thin-ply composite materials has rapidly increased due to their tailorable mechanical properties and design flexibility. Considering an adhesively bonded composite joint, peel stress stands out as a key contributor leading to failure among other primary stress factors. Therefore, the reinforcement of carbon fiber-reinforced polymer (CFRP) laminates throughout the thickness could be considered as an approach to improve the joint strength. Using thin plies locally between the conventional CFRP layers in a laminate can enhance the strength, as the sudden change in stiffness means that the load transfer is not monotonous. Consequently, the following study examined the effect of altering thin plies gradually throughout the thickness on the behaviour of the CFRP laminates when subjected to transverse tensile loading. To achieve this goal, the CFRP laminates were gradually modified by using different commercially accessible prepreg thin plies, leading to an improved overall structural performance by reducing stress concentrations. Besides conducting an experimental study, a numerical assessment was also carried out utilizing Abaqus software with a Representative Volume Element (RVE) at the micro scale. The comparison of reference configurations, which involved various thin plies with different thicknesses and traditional CFRP laminates, with the suggested gradual configuration, demonstrated a notable enhancement in both strength and material cost. Furthermore, the proposed RVE model showed promising capability in accurately forecasting the strength of fabricated laminates.
40
Xin, Zhuangzhuang, Wei Xu, Defa Liu, and Jilu Duan. "Research on Energy Absorption Characteristics of Bouligand Biomimetic Structure Based on CFRP Composite Materials." Sustainability 15, no. 13 (June 21, 2023): 9911. http://dx.doi.org/10.3390/su15139911.
Анотація:
Enhancing the impact resistance performance of carbon fiber-reinforced polymer (CFRP) laminates stands as a prominent research focus among various nations. Existing studies have shown a tendency towards arbitrary selection of the inter-ply helix angle values in CFRP laminates, which is accompanied by a limited number of samples representing the chosen helix angles. However, existing studies have shown a relatively random selection of spiral angle values between CFRP laminates, and the sample size of selected spiral angles is limited, posing certain limitations. In order to tackle this problem, we have employed a systematic arrangement of combinations to select the optimal helix angle for CFRP laminates. Inspired by the biological structures of Bouligand, we have sequentially chosen 19 distinct sets of helix angles, aiming to overcome the inherent limitations and enhance the research outcomes in this field. In this study, we established 19 finite element models to investigate the behavior of Bouligand-inspired CFRP composite panels under high-velocity bullet impact. The models were created by selecting 19 sets of helix angles within the range of 0 to 90° with a 5° interval. The results show that the energy absorption of the Bouligand layer-stacking composite plate is better than that of the conventional plate. The optimal spiral angles of the CFRP laminate are 25° and 30°, and the energy absorption characteristics of the laminate are the best at these angles. The impact resistance is also the best at these angles. The energy absorption of the Bouligand layer-stacking composite plate is 396% higher in absorbed internal energy and 361% higher in absorbed kinetic energy compared to the conventional layer-stacking composite plate, significantly improving the ballistic performance of the CFRP bulletproof material and providing a reference for the design of individual protection equipment.
41
Meon, M. S., N. H. Mohamad Nor, S. Shawal, J. B. Saedon, M. N. Rao, and K. U. Schröder. "On the Modelling Aspect of Low-Velocity Impact Composite Laminates." journal of Mechanical Engineering 17, no. 2 (July 15, 2020): 13–25. http://dx.doi.org/10.24191/jmeche.v17i2.15297.
Анотація:
Composites suffer a degradation of structural stiffness due to various types of impact loading resulting in damage which is difficult to observe from the surface of the structure. The paper deals with the finite element model (FEM) to study the possible modelling procedures in low-velocity impact (LVI) and failure mechanism of carbon fiber reinforced polymer (CFRP) composite laminate of CCF300/epoxy and its structural responses. In finite element calculation, a proposed three-dimensional progressive damage model is used to determine the intralaminar damage, whereas the cohesive contact formulation is employed to analyse the interlaminar damage. The failure model performances are validated and verified based on different boundary conditions while maintaining the impact energy. Through simulation, the variation in boundary conditions significantly changes the structural responses and energy absorption of the laminates. It is hoped this study will be a great tool in determining the different composite impact scenarios.
42
Seo, Hyoung Seock, Ho Yun Jang, and Ho Hwan Chun. "Investigation of Tensile Strength of Composite Laminate under Diverse Environment Conditions." Materials Science Forum 813 (March 2015): 169–80. http://dx.doi.org/10.4028/www.scientific.net/msf.813.169.
Анотація:
To investigate ocean environmental effects of salt water and xenon light, salt water spray test and xenon test were performed on long immersion hours. CFRP (Carbon Fiber Reinforced Polymer) specimens were prepared for salt water spray experiment, xenon light exposure experiment and mechanical tensile tests. The composite specimens with total 15 layers were manufactured with diverse fiber orientations of [0°]15, [90°]15 and [0°3/+45°2/-45°2/90°/-45°2/+45°2/0°3]. After applying environmental conditions, the tensile strength was compared with the tensile strength without environmental conditions. The influence of different fiber orientation was also investigated, respectively. Finally, the results showed that the tensile strength of composite specimens was affected by salt water and xenon light clearly.
43
Zainurrahman, Eko Darma, and Sri Nuryati. "Carbon Fiber Reinforced Polymer Sebagai Perkuatan Lentur pada Balok Beton." BENTANG : Jurnal Teoritis dan Terapan Bidang Rekayasa Sipil 8, no. 1 (January 15, 2020): 20–28. http://dx.doi.org/10.33558/bentang.v8i1.1947.
Анотація:
Concrete Beams can experience a sudden collapse when overload because of its brittle characteristic. The use of Carbon Fiber Reinforced Polymer (CFRP) on concrete beams externally as external confinement is predicted to improve concrete mechanics properties, increase the ductility and capacity of concrete, and the flexural strength of concrete beams. An experimental study on the reinforcement of concrete beams with Carbon Fiber Reinforced Polymer (CFRP) was carried out to estimate the effectiveness of CFRP on concrete structures as a concrete beam flexural reinforcement material. Two types of concrete beams are provided in this study to test the flexural strengthening effect of the externally bound CFRP composite. First type of concrete beam used for testing is a normal concrete beams, whereas the second tested beam, the CFRP was laminated by coating the beams with Fiber. The dimensions of both types are 15cm x15cm with a length of 55cm footing range. Testing result obtained the compressive strength was 23,29 MPa, flexural strength of normal and CRFP concretes were 33,41 Kg/cm2 and 48,07 Kg/cm2 respectively. It was concluded that the use of CRFP at the concrete beam increases flexural strength up to 44% with the ratio of 143 %.
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M.A. Gharib, W.H. Khushefati, M.A. Khedr, and E.Y. Sayed-Ahmed. "Steel beams strengthened with prestressed CFRP laminate: is there a need for laminate prestressing?" Electronic Journal of Structural Engineering 16 (January 1, 2016): 53–62. http://dx.doi.org/10.56748/ejse.16210.
Анотація:
Strengthening structural members using Carbon Fiber Reinforced Polymer (CFRP) laminate is an effective method to increase their strength. Prestressing the CRFP laminate prior to attaching them to a steel beam can delay the common premature debonding, which is the predominant failure mode when loading such composite elements in flexure. Following a previously published experimental investigation, this paper presents the results of a finite element simulation of steel I-beams strengthened with bonded and mechanically anchored prestressed CFRP laminate subjected to flexural loading. The numerical analysis adopts a Cohesive Zone Model (CZM) technique to simulate the separation between the CFRP laminate and the steel beam in order to model the debonding failure mode. The accuracy of the finite element model is verified by comparing its results to those of the previously published experimental investigation, which was carried out on steel I-beams strengthened with prestressed CFRP laminate in deferent configurations. The numerical model is then used to evaluate the effect of changing the level of the prestressing force on the strengthened beams performance. It is found that the CFRP prestressing enhances the yield and ultimate load carrying capacity of the beams and delays the typical premature debonding failure up to a certain level of laminate prestressing.
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Zhang, Nan, Shuai Gao, Meili Song, Yang Chen, Xiaodong Zhao, Jianguo Liang, and Jun Feng. "A Multiscale Study of CFRP Based on Asymptotic Homogenization with Application to Mechanical Analysis of Composite Pressure Vessels." Polymers 14, no. 14 (July 11, 2022): 2817. http://dx.doi.org/10.3390/polym14142817.
Анотація:
The application of composites is increasingly extensive due to their advanced properties while the analysis still remains complex on different scales. In this article, carbon fiber reinforced polymer (CFRP) is modeled via asymptotic homogenization employing a representative volume element (RVE) with periodic boundary conditions. A multiscale mechanical model of CFRP is established to bridge the microscopic model, mesoscopic model, and macroscopic model. According to asymptotic homogenization, the coefficients of the material constitutive equation are calculated with volume-averaged stress and strain. Using the homogenized materials properties of CFRP, the tensile experiments of composite layers with the layout of [(0∘/60∘/0∘/−60∘)4] are carried out to validate asymptotic homogenization method. The results indicated that the asymptotic homogenization approach can be used to calculate the homogenized elastic moduli and Poisson’s ratio of the whole structure, where the numerical results are basically consistent with test data. The sequent homogenized CFRP laminate model is applied to the mechanical analysis of type III composite pressure vessels, whereby burst pressure is accurately predicted. This work might shed some light on multiscale analysis of composite pressure vessels.
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Arnautov, Aleksandr K., Vladimir Kulakov, Janis Andersons, Viktor Gribniak, and Algirdas Juozapaitis. "Experimental investigation on stiffness and strength of single-lap z-pinned joints in a laminated CFRP stress-ribbon strip." Baltic Journal of Road and Bridge Engineering 11, no. 2 (June 27, 2016): 120–26. http://dx.doi.org/10.3846/bjrbe.2016.14.
Анотація:
Carbon fiber-reinforced polymer (carbon-polymer) is an advanced lightweight composite material with high strength and excellent resistance to corrosion and fatigue. Over the past decades, application of fiber-reinforced polymers has been spread from the aerospace to other branches of industry such as automobile and civil engineering. Unidirectional carbon-polymers have a high potential for replacing steel in tensile members. Recently, the first carbonpolymer stress-ribbon bridge has been constructed in Germany. The non-laminated strip-loop carbon-polymer thin strips were used as the load bearing components in this bridge. In comparison with the laminated components, the applied cables are characterized by a more uniform strain distribution though reduced structural integrity. Alternative jointing technologies of carbon-polymer laminates are considered in this paper with an intention to increase the structural integrity and reliability of the production. Tensile behavior of the single-lap joints was investigated experimentally. Three types of the joints were considered. Adhesive joint was set as the reference. The overlap region of the mechanically fastened joints was produced using 9, 25, or 36 steel needles (z-pins) of 1 mm diameter. The proposed hybrid joints were additionally connected with adhesive increasing the load-bearing capacity of the reference joint up to 230%. Concerning the brittle fracture of the adhesive counterparts, the extended progressive failure process within the hybrid joints is responsible for the improvement.
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Santos, Mário, Jaime Santos, and Lorena Petrella. "Computational Simulation of Microflaw Detection in Carbon-Fiber-Reinforced Polymers." Electronics 11, no. 18 (September 8, 2022): 2836. http://dx.doi.org/10.3390/electronics11182836.
Анотація:
The evaluation of microflaws in carbon-fiber-reinforced composite laminate (CFRP) via ultrasound requires the knowledge of some important factors in addition to its structural composition. Since the laminates are heterogeneous, the high-frequency requirements to acquire high-resolution signals have limitations due to the great scattering that prevents good signal-to-noise ratios. Additionally, the ultrasonic probe’s spatial and lateral resolution characteristics are important parameters for determining the detectability level of microflaws. Modelling appears as a good approach to evaluating the abovementioned factors and the probability of detection of defects in the micron range because it makes it possible to reduce the time and cost associated with developments based on experimental tests. Concerning the subject of this work, simulation is the best way to evaluate the detectability level of the proposed defects since experimental samples are not available. In this work, the simulation was implemented using the Matlab k-Wave toolbox. A 2D matrix for mimicking a CFRP was constructed with 1 μm of resolution. Four different defect types in the micron range were created in the matrix. The simulated and experimental results presented good agreement. It was concluded that the highest frequency probe that could be used to detect the simulated defects without ambiguity was 25 MHz.
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Śliwa-Wieczorek, Klaudia, Krzysztof Adam Ostrowski, Justyna Jaskowska-Lemańska, and Anna Karolak. "The Influence of CFRP Sheets on the Load-Bearing Capacity of the Glued Laminated Timber Beams under Bending Test." Materials 14, no. 14 (July 18, 2021): 4019. http://dx.doi.org/10.3390/ma14144019.
Анотація:
Composite materials are increasingly used to strengthen existing structures or new load-bearing elements, also made of timber. In this paper, the effect of the number of layers of Carbon Fiber Reinforced Polymer (CFRP) on the load-bearing capacity and stiffness of Glued Laminated Timber beams was determined. Experimental research was performed on 32 elements—a series of eight unreinforced beams, and three series of eight reinforced beams: with one, three and five layers of laminate each. The beams with a cross-section of 38 mm × 80 mm and a length of 750 mm were subjected to the four-point bending test according to standard procedure. For each series, destructive force, deflection, mode of failure, and equivalent stiffness were determined. In addition, for the selected samples, X-ray computed tomography was performed before and after their destruction to define the quality of the interface between wood and composite. The results of the conducted tests and analyses showed that there was no clear relationship between the number of reinforcement layers and the load-bearing capacity of the beams and their stiffness. Unreinforced beams failed due to tension, while reinforced CFRP beams failed due to shear. Despite this, a higher energy of failure of composite-reinforced elements was demonstrated in relation to the reference beams.
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Liu, Xiang, Weimin Gu, Qiwen Liu, Xin Lai, and Lisheng Liu. "Damage of Hygrothermally Conditioned Carbon Epoxy Composites under High-Velocity Impact." Materials 11, no. 12 (December 12, 2018): 2525. http://dx.doi.org/10.3390/ma11122525.
Анотація:
The influence of hygrothermal aging on high-velocity impact damage of carbon fiber-reinforced polymer (CFRP) laminates is investigated. Composite laminate specimens were preconditioned in water at 70 °C. The laminates were subsequently impacted by flat-, sphere-, and cone- ended projectiles with velocities of 45, 68, and 86 m/s. The incident and residual velocities were collected during the impact test. The impact-induced damages were measured by ultrasonic C-scan, a digital microscope system, and a scanning electron microscope. The results show that the hygrothermally conditioned laminates offer a higher energy absorption during high-velocity impact. Due to the weakening of the interlaminar properties, the hygrothermally conditioned laminates are more susceptible to delamination failure, and shear-induced debonding dominates. The projected delamination area increases with the increment of impact velocity. The damaged region becomes close to a circular shape after hydrothermal conditioning, and close to a rhomboidal shape for the dry specimens.
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Jumahat, A., C. Soutis, F. R. Jones, and A. Hodzic. "Improved Compressive Properties of a Unidirectional Cfrp Laminate Using Nanosilica Particles." Advanced Composites Letters 19, no. 6 (November 2010): 096369351001900. http://dx.doi.org/10.1177/096369351001900604.
Анотація:
The effect of nanosilica particles on the compressive properties of a unidirectional (UD) HTS40/828 carbon fibre reinforced polymer (CFRP) composite was studied. A series of nanomodified CFRP composite was fabricated using 3.6-19.7 vol.% nanosilica-modified epoxy resin. Static uniaxial compression tests were conducted on [0]8 laminate specimens of 12 mm gauge length to evaluate the compressive properties. It was found that the compressive modulus and strength of nanomodified UD system were improved with increasing nanosilica content without any significant reduction in failure strain. The presence of spherical silica nanoparticles stiffened the epoxy matrix and offered a better lateral support to the carbon fibre. Therefore, the compressive properties were improved significantly in comparison with the unmodified CFRP system. These results suggested that the interaction between the nanomodified epoxy and the carbon fibre is very good therefore the load is successfully transferred via the interface to give higher resistance against deformation when it was loaded in compression.