scholarly journals Effects of the Longitudinal Surface Roughness on Fiber Pull-Out Behavior in Carbon Fiber-Reinforced Epoxy Resin Composites

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Yin Yao ◽  
Shaohua Chen
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
Epoxy Resin ◽  
Carbon Fibers ◽  
Fiber Reinforced ◽  
Fiber Stress ◽  
Pull Out ◽  
Carbon Fiber Reinforced

Surface modifications are known as efficient technologies for advanced carbon fibers to achieve significant improvement of interface adhesion in composites, one of which is to increase the surface roughness in the fiber's longitudinal direction in practice. As a result, many microridges and grooves are produced on carbon fiber's surfaces. How does the surface roughness influence the carbon fiber's pull-out behavior? Are there any restrictions on the relation between the aspect ratio and surface roughness of fibers in order to obtain an optimal interface? Considering the real morphology on carbon fiber's surface, i.e., longitudinal roughness, an improved shear-lag theoretical model is developed in this paper in order to investigate the interface characteristics and fiber pull-out for carbon fiber-reinforced thermosetting epoxy resin (brittle) composites. Closed-form solutions to the carbon fiber stress are obtained as well as the analytical load-displacement relation during pullout, and the apparent interfacial shear strength (IFSS). It is found that the interfacial adhesion and the apparent IFSS are effectively strengthened and improved due to the surface roughness of carbon fibers. Under a given tensile load, an increasing roughness will result in a decreasing fiber stress in the debonded zone and a decreasing debonded length. Furthermore, it is interesting to find that, for a determined surface roughness, an optimal aspect ratio, about 30∼45, of carbon fibers exists, at which the apparent IFSS could achieve the maximum. Comparison to the existing experiments shows that the theoretical model is feasible and reasonable to predict the experimental results, and the theoretical results should have an instructive significance for practical designs of carbon/epoxy composites.

scholarly journals Orthogonal Experimental Analysis and Mechanism Study on Electrochemical Catalytic Treatment of Carbon Fiber-Reinforced Plastics Assisted by Phosphotungstic Acid

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1866
Author(s):  
Chun Pei ◽  
Peiheng Guo ◽  
Ji-Hua Zhu
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Carbon Fibers ◽  
Phosphotungstic Acid ◽  
Degradation Mechanism ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Carbon Fiber Reinforced

Preserving the integrity of carbon fibers when recycling carbon-fiber-reinforced plastics (CFRPs) has been unfeasible due to the harsh reaction conditions required to remove epoxy resin matrixes, which adversely affect the properties of carbon fibers. We establish a practicable and environmentally friendly reclamation strategy for carbon fibers. Carbon fibers are recycled from waste CFRPs by an electrochemical catalytic reaction with the assistance of phosphotungstic acid (PA), which promotes the depolymerization of diglycidyl ether of bisphenol A/ethylenediamine (DGEBA/EDA) epoxy resin. The removal rate, mechanical strength, and microstructure of the recycled carbon fibers are analyzed to explore the mechanism of the electrochemical treatment. The influence of three factors—current density, PA concentration, and reaction time—are studied via an orthogonal method. Range analysis and variance analysis are conducted to investigate the significance of the factors. The optimal conditions are determined accordingly. The underlying CFRP degradation mechanism is also investigated.

scholarly journals Preparation of Nano-SiO2/Carbon Fiber-Reinforced Concrete and Its Influence on the Performance of Oil Well Cement

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yanming Li ◽  
Xiaoyang Guo ◽  
Junlan Yang ◽  
Ming Li
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Fiber Reinforced Concrete ◽  
Cement Stone ◽  
Oil Well ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Oil Well Cement ◽  
Carbon Fiber Reinforced ◽  
Well Cement

In view of the oilfield well thin oil layer, small gap, and side drilling cementing after perforating and subsequent stimulation caused by the cement ring embrittlement (i.e., secondary channeling), the preparation of nano-SiO2/carbon fiber-reinforced body and its influence on the performance of oil well cement were studied to improve the cement stone and enhance its adaptability to oil well pressure in this study. Carbon fibers were treated by liquid phase oxidation and a coupling agent, and the “grafting to” was used to bond nano-SiO2 and carbon fibers. It was found that the mechanical properties of the enhanced cement stone are far better than those of the blank cement stone. The compressive strength and tensile strength of the enhanced oil well cement stone were increased by 25% and 26%, respectively, compared with those of the blank oil well cement sample; the modulus of elasticity was reduced by 29%. Finally, the enhancement mechanism of SiO2/carbon fiber reinforcement on cement stone was explored by infrared, scanning electron microscopy, and XRD patterns. The deflection effect, pull-out effect, and bridging effect of crack were obtained.

scholarly journals Effect of Tool Wear on Quality of Carbon Fiber Reinforced Polymer Laminate during Edge Trimming

2013 ◽  
Vol 325-326 ◽  
pp. 34-39 ◽  
Author(s):  
Hossein Hamedanianpour ◽  
Jean François Chatelain
Keyword(s):  
Surface Roughness ◽  
Carbon Fiber ◽  
Tool Wear ◽  
Matrix Cracking ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Fiber Reinforced ◽  
Coated Carbide ◽  
Cutting Speeds

Polymer matrix composites, particularly carbon fiber reinforced polymers (CFRPs) are widely used in various high technology industries, including aerospace, automotive and wind energy. Normally, when CFRPs are cured to near net shape, finishing operations such as trimming, milling or drilling are used to remove excess materials. The quality of these finishing operations is highly crucial at the level of final assembly. The present research aims to study the effect of cutting tool wear on the resulting quality for the trimming process of high performance CFRP laminates, in the aerospace field. In terms of quality parameters, the study focuses on surface roughness and material integrity (uncut fibers, fiber pull-out, delamination or thermal damage of the matrix), which could jeopardize the mechanical performance of the components. In this study, a 3/8 inch diameter CVD diamond coated carbide tool with six straight flutes was used to trim 24-ply carbon fiber laminates. Cutting speeds ranging from 200 m/min to 400 m/min and feed rates ranging from 1524 mm/min to 4064 mm/min were used in the experiments. The results obtained using a scanning electron microscope (SEM) showed increasing defect rates with increased tool wear. The worst surface integrity, including matrix cracking, fiber pull-out and empty holes, was also observed for plies oriented at -45 degrees. For the surface finish, it was observed that for the studied cutting length ranges, an increase in tool wear resulted in a decrease in surface roughness. Regarding tool wear, a lower rate was observed at lower feed rates and higher cutting speeds, while a higher tool wear rate was observed at intermediate values of our feed rate and cutting speed ranges.

Graphene oxide modified carbon fiber reinforced epoxy composites

2020 ◽  
Vol 40 (5) ◽  
pp. 415-420 ◽  
Author(s):  
Yasin Altin ◽  
Hazal Yilmaz ◽  
Omer Faruk Unsal ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Graphene Oxide ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Spray Coating ◽  
Sem Analysis ◽  
Epoxy Composites ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Quick Method ◽  
Carbon Fiber Reinforced

AbstractThe interfacial interaction between the fiber and matrix is the most important factor which influences the performance of the carbon fiber-epoxy composites. In this study, the graphitic surface of the carbon fibers was modified with graphene oxide nanomaterials by using a spray coating technique which is an easy, cheap, and quick method. The carbon fiber-reinforced epoxy matrix composites were prepared by hand layup technique using neat carbon fibers and 0.5, 1 and 2% by weight graphene oxide (GO) modified carbon fibers. As a result of SEM analysis, it was observed that GO particles were homogeneously coated on the surface of the carbon fibers. Furthermore, Young's modulus increased from 35.14 to 43.40 GPa, tensile strength increased from 436 to 672 MPa, and the elongation at break was maintained around 2% even in only 2% GO addition.

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