scholarly journals Experimental investigation of the synergistic effects of moisture and freeze-thaw cycles on carbon fiber vinyl-ester composites

2017 ◽  
Vol 52 (7) ◽  
pp. 919-930 ◽  
Author(s):  
Maen Alkhader ◽  
Xuedong Zhai ◽  
Fu-Pen Chiang
Keyword(s):  
Carbon Fiber ◽  
Structural Properties ◽  
Vinyl Ester ◽  
Synergistic Effects ◽  
Offshore Structures ◽  
Fiber Reinforced ◽  
Freeze Thaw ◽  
Carbon Fiber Reinforced ◽  
The Individual

Carbon fiber-reinforced vinyl-ester polymer composites are increasingly used as structural members in applications (e.g., marine crafts and offshore structures) where they can be frequently exposed to the environmental elements of moisture and cold temperature fluctuations that cause freeze-thaw cycles. These harsh elements can individually and possibly synergistically damage carbon fiber-reinforced vinyl-ester composites. More importantly, their damage can accumulate over time and significantly degrade the structural properties, long-term integrity and durability of carbon fiber-reinforced vinyl-ester composites. This work experimentally investigates the individual and cooperative degrading effects of moisture and freeze-thaw cycles on the structural properties of carbon fiber-reinforced vinyl-ester composites, particularly on their flexural stiffness and strength. Results show that the combined damaging effects of moisture and freeze-thaw cycles are more significant than their individual effects, confirming the synergy between the damage mechanisms of the two elements.

Effects of high pressure on the crystallization of carbon fiber reinforced polyetheretherketone (CF/PEEK) laminate composites

1990 ◽  
Vol 48 (4) ◽  
pp. 876-877
Author(s):  
Hong-Ming Lin ◽  
C. H. Liu ◽  
R. F. Lee
Keyword(s):  
High Pressure ◽  
Carbon Fiber ◽  
Sample Surface ◽  
High Yield ◽  
Fiber Reinforced ◽  
Laminate Composites ◽  
Peek Composite ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Reinforced

Polyetheretherketone (PEEK) is a crystallizable thermoplastic used as composite matrix materials in application which requires high yield stress, high toughness, long term high temperature service, and resistance to solvent and radiation. There have been several reports on the crystallization behavior of neat PEEK and of CF/PEEK composite. Other reports discussed the effects of crystallization on the mechanical properties of PEEK and CF/PEEK composites. However, these reports were all concerned with the crystallization or melting processes at or close to atmospheric pressure. Thus, the effects of high pressure on the crystallization of CF/PEEK will be examined in this study.The continuous carbon fiber reinforced PEEK (CF/PEEK) laminate composite with 68 wt.% of fibers was obtained from Imperial Chemical Industry (ICI). For the high pressure experiments, HIP was used to keep these samples under 1000, 1500 or 2000 atm. Then the samples were slowly cooled from 420 °C to 60 °C in the cooling rate about 1 - 2 degree per minute to induce high pressure crystallization. After the high pressure treatment, the samples were scanned in regular DSC to study the crystallinity and the melting temperature. Following the regular polishing, etching, and gold coating of the sample surface, the scanning electron microscope (SEM) was used to image the microstructure of the crystals. Also the samples about 25mmx5mmx3mm were prepared for the 3-point bending tests.

Experimental study on the bond behavior of the CFRP-steel interface under the freeze–thaw cycles

2019 ◽  
Vol 54 (1) ◽  
pp. 13-29 ◽  
Author(s):  
Yu-Yang Pang ◽  
Gang Wu ◽  
Hai-Tao Wang ◽  
Zhi-Long Su ◽  
Xiao-Yuan He
Keyword(s):  
Carbon Fiber ◽  
Bond Length ◽  
Ultimate Load ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Bond Slip ◽  
Freeze Thaw ◽  
Reinforced Polymer ◽  
Carbon Fiber Reinforced

The bond–slip degradation relationship between carbon fiber-reinforced polymer and steel in a freeze–thaw environment is crucial to evaluate the long-term service performance of steel structures strengthened with carbon fiber-reinforced polymer plates. However, limited studies on the durability and long-term performance of the carbon fiber-reinforced polymer-steel-bonded interface are the major obstacle for the application of carbon fiber-reinforced polymer plates in strengthening steel structures. This paper reports an experimental study to investigate the effects of the carbon fiber-reinforced polymer bond length and the freeze–thaw cycles on the bond behavior of the carbon fiber-reinforced polymer-steel-bonded interface. The three-dimensional digital image correlation technique is applied to obtain displacements and strains on the surface of the single-shear specimen. The experimental results present herein include the failure mode, the ultimate load, the carbon fiber-reinforced polymer strain distribution, the displacement distribution, and the bond–slip relationship. The results show that the ultimate load increases with increasing bond length until a certain bond length value is reached, after which the ultimate load remained approximately constant, and the ultimate loads of carbon fiber-reinforced polymer-steel interface decrease gradually under freeze–thaw cycles. The bond–slip parameters degradation models are proposed, and the bond–slip degradation relationship under the freeze–thaw cycles is established. Finally, the bond–slip degradation relationship is confirmed through comparisons with the experimental results.

Synergistic Effects of Fatigue and Marine Environments on Carbon Fiber Vinyl-Ester Composites

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Arash Afshar ◽  
Maen Alkhader ◽  
Chad S. Korach ◽  
Fu-Pen Chiang
Keyword(s):  
Carbon Fiber ◽  
Fatigue Damage ◽  
Vinyl Ester ◽  
Structural Integrity ◽  
Synergistic Effects ◽  
Fiber Reinforced ◽  
Damage Models ◽  
Frp Composites ◽  
Fatigue Damage Accumulation ◽  
Damaging Effects

Fiber-reinforced polymer (FRP) composites used in the construction of composite-based civil and military marine crafts are often exposed to aggressive elements that include ultraviolet radiation, moisture, and cyclic loadings. With time, these elements can individually and more so cooperatively degrade the mechanical properties and structural integrity of FRP composites. To assist in increasing the long-term reliability of composite marine crafts, this work experimentally investigates the cooperative damaging effects of ultraviolet (UV), moisture, and cyclic loading on the structural integrity of carbon fiber reinforced vinyl-ester marine composite. Results demonstrate that UV and moisture can synergistically interact with fatigue damage mechanisms and accelerate fatigue damage accumulation. For the considered composite, damage and S–N curve models with minimal fitting constants are proposed. The new models are derived by adapting well-known cumulative fatigue damage models to account for the ability of UV and moisture to accelerate fatigue damaging effects.

scholarly journals Durability of an Epoxy Resin and Its Carbon Fiber- Reinforced Polymer Composite upon Immersion in Water, Acidic, and Alkaline Solutions

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 614 ◽  
Author(s):  
Arya Uthaman ◽  
Guijun Xian ◽  
Sabu Thomas ◽  
Yunjia Wang ◽  
Qiang Zheng ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Alkaline Solutions ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Cfrp Composites ◽  
Carbon Fiber Reinforced

The usage of polymer composites in various engineering fields has increased. However, the long-term service performance of such materials under aggressive conditions is still poorly understood, which limits the development of safe and economically effective designs. In this study, the aging of an epoxy resin and its carbon fiber-reinforced polymer (CFRP) composites upon immersion in water, acidic, and alkaline solutions was evaluated at different temperatures. The service life of the CFRP composites under various conditions could be predicted by the Arrhenius theory. The thermal and mechanical analysis results indicated that the CFRP composites were more vulnerable to HCl owing to the higher moisture absorption and diffusion of HCl into their cracks. The scanning electron microscopy results showed that the polymer matrix was damaged and degraded. Therefore, to allow long-term application, CFRP composites must be protected from acidic environments.

scholarly journals Friction behavior of innovative carbon friction linings for wet multi-plate clutches

2021 ◽  
Vol 85 (1) ◽  
pp. 115-127
Author(s):  
U. Stockinger ◽  
D. Groetsch ◽  
F. Reiner ◽  
K. Voelkel ◽  
H. Pflaum ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Experimental Studies ◽  
Good Control ◽  
Screening Tests ◽  
Published Data ◽  
Fiber Reinforced ◽  
Friction Behavior ◽  
Transfer Capability ◽  
Carbon Fiber Reinforced

AbstractThe torque transfer capability as well as long-term endurance are essential for wet multi-plate clutches. The quality of the torque transmission process largely depends on the tribological system consisting of friction pairing, lubricant and applied loads. The requirements on friction linings in wet multi-plate clutches increase continuously due to stricter CO2 reduction regulations and the demand of higher power densities.There is a lack of published data and information about the friction behavior of modern Carbon friction linings in wet multi-plate clutch applications, although these friction materials have successfully proven their performance capabilities over the last two decades in synchronizers. Therefore, this article presents results from experimental studies on the friction behavior of innovative Carbon friction linings carried out on a component test rig. Friction screening tests were performed with Carbon-fiber reinforced plastic (CFRP) and Carbon-fiber reinforced Carbon (C/C) linings in brake and constant slip operation. Furthermore, our research included long-term tests with different lubricants (engine/marine/tractor oil).Results show that modern Carbon friction linings can offer advantages over other materials. In the friction screening (brake and constant slip operations) and long-term tests, the torque transfer capability of both friction linings is very stable, even at high specific loads—sliding velocities near 30 m/s and axial pressures of 2.5 MPa. Influences of sliding velocity, pressure and lubricant on the friction performance are presented. Furthermore, the gradient of the Coefficient of Friction (CoF) curve usually decreases at the end of the engagement to enable good control and shift comfort.

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