Effect mechanism of plain-woven structure of carbon fiber on CFRP cutting

Based on the previously conducted analytical study of the destruction of conducting composites by lightning currents, methods for increasing their lightning resistance are considered. To substantiate these methods, an analysis of the current distribution at different ratios of transverse and longitudinal resistivity was carried out. One of the methods using conductive additives in the composition of the binder material allows you to influence the anisotropy of the conductive medium of carbon fiber. The parameters of the range of the degree of anisotropy of carbon fiber are proposed to achieve uniform current spreading and reduce the radius of destruction of the composite by lightning currents. The formula for the fracture radius in the absence of anisotropy is obtained and estimated calculations are performed. The method of reinforcing carbon fiber with thin wires to increase its lightning resistance is considered. Calculated expressions are found for estimating the weight, the number of delays per unit area, and the absence of overheating. Comparisons of weight characteristics for various reinforcing materials are carried out and a conclusion is made on their effectiveness. The advantages and disadvantages of this method of protection are considered. The third way to increase the lightning resistance of the composite suggests using a carbon fiber material with a woven structure as a protective coating. This protection reduces the energy release in the material and the size of the damage. It is concluded that it is necessary to control the lightning protection parameters and choose a coating with the required characteristics. The principles and criteria of lightning protection for real carbon fiber plastics will be considered in subsequent works.

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Effect Mechanism of Plain Woven Structure of Carbon Fiber on CFRP Cutting

10.21203/rs.3.rs-939156/v1 ◽

2021 ◽

Author(s):

Guojun Dong ◽

Fei Su ◽

Chunjie Li ◽

Lei Zhen ◽

Bing Chen

Keyword(s):

Carbon Fiber ◽

Three Dimensional ◽

Cutting Speed ◽

Feed Speed ◽

Stress Concentrations ◽

Cutting Mechanism ◽

Fem Model ◽

Reinforced Plastic ◽

Occurrence Mechanism ◽

Woven Structure

Abstract Carbon fiber-reinforced plastic (CFRP) is increasingly employed as structural components for aircrafts in aerospace. The plain woven CFRP is more commonly used than the UD-CFRP. The machining-induced damages are easy to occur. The influence of the plain-woven structure on the cutting mechanism and the defects occurrence mechanism are seldom studied in detail. In this paper, the three-dimensional FEM model of plain woven CFRP is established. The occurrence and propagation of the delamination are investigated. The results indicate that the stress concentrations are easy to occur at the junction of warp and fill bundles near the cutting position. The plain-woven structure can block the transfer of stress and the crack propagation. When θ=90°, the damages of the fill fibers and the crack of the interface are easy to occur. When θ=45°, the step-like fracture is formed in both of the warp and the fill bundles, especially in the fill bundles. Under the same cutting conditions, the exit delamination of the plain-woven CFRP is obviously less than that of the UD-CFRP. The delamination greatly increases with the increase of the feed speed. The delamination decreases with the increase of the cutting speed. The delamination is closely related to the instantaneous cutting position of the cutter.

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Rotary Ultrasonic Machining of CFRP Composites: Effects of Carbon Fiber Reinforcement Structure

Volume 2: Processes; Materials ◽

10.1115/msec2019-3014 ◽

2019 ◽

Author(s):

Dongzhe Zhang ◽

Hui Wang ◽

Yingbin Hu ◽

Xiaoxu Chen ◽

Weilong Cong ◽

...

Keyword(s):

Surface Roughness ◽

Carbon Fiber ◽

Fiber Reinforcement ◽

Ultrasonic Machining ◽

Rotary Ultrasonic Machining ◽

Reinforcement Structure ◽

Cfrp Composites ◽

Carbon Fiber Reinforcement ◽

Hole Making ◽

Woven Structure

Abstract Carbon fiber reinforced plastic (CFRP) composites have been widely used in many applications due to their superior properties of high strength-weight ratio, high stiffness, and high wear resistance. For assembly purposes, hole making is necessary for different applications of CFRP composites. Rotary ultrasonic machining (RUM) has been proposed and investigated for hole making of CFRP composites. Studies on the effects of machining variables, tool variables, workpiece orientation, and cooling conditions on output variables in RUM of CFRP composites have been investigated. The carbon fiber reinforcement structures of CFRP composites also affect the machining performances and part’s quality. However, there is no reported investigation on studying carbon fiber reinforcement structures’ influences in RUM of CFRP composites. Experiments were conducted for this paper to investigate the effects of carbon fiber reinforcement structure on cutting force, torque, and surface roughness. Three major conclusions can be drawn from the results of this experimental investigation. First, CFRP composites with unidirectional structure led to the smallest cutting force and torque, followed by CFRP composites with plain woven structure and twill woven structure. Second, the surface roughness on CFRP composites with plain woven structure was the smallest, followed by the CFRP composites with unidirectional structure and twill woven structure. In addition, CFRP composites with different reinforcement structures have the same tendencies of output variables with different machining variables.

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Quantifying hole quality through geometry accuracy and surface qualities in rotary ultrasonic machining of carbon fiber–reinforced plastic composites

Advances in Mechanical Engineering ◽

10.1177/1687814020945473 ◽

2020 ◽

Vol 12 (8) ◽

pp. 168781402094547

Author(s):

Dongzhe Zhang ◽

Hui Wang ◽

Weilong Cong

Keyword(s):

Carbon Fiber ◽

Carbon Fiber Reinforced Plastic ◽

Fiber Reinforced ◽

Rotary Ultrasonic Machining ◽

Hole Quality ◽

Fiber Reinforced Plastic ◽

Plastic Composites ◽

Reinforced Plastic ◽

Carbon Fiber Reinforced ◽

Woven Structure

Rotary ultrasonic machining has been approved as an effective and efficient hole making process for carbon fiber–reinforced plastic composites. Hole quality plays an important role in assembling carbon fiber–reinforced plastic components and can be affected by the carbon fiber reinforcement structures. In this study, experiments are conducted to assess hole quality in carbon fiber–reinforced plastic composites with three carbon fiber reinforcement structures under different combinations of machining variables. Hole quality is quantified through geometrical accuracy (perpendicularity, cylindricity, and hole diameter) and surface qualities (delamination and surface roughness). Results show that the highest level of interlacement among yarn of plain woven structure induce the highest level of compression to the workpiece and the largest amount of additional material removal, leading to the largest perpendicularity and hole diameter. The worst fabric integrity of unidirectional structure generates the largest amount of non-uniform material removal on the machined surface, resulting in the largest cylindricity. It is also found that compared with woven structures, unidirectional structure is more likely to induce push-out delamination due to its smaller critical energy release rate. The lowest constancy of the fabric in twill woven structure leads to the largest surface roughness.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177519 ◽

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.

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Enhanced performance of supercapacitors by constructing a “mini parallel-plate capacitor” in an electrode with high dielectric constant materials

Journal of Materials Chemistry A ◽

10.1039/d0ta04364h ◽

2020 ◽

Vol 8 (32) ◽

pp. 16661-16668

Author(s):

Huayao Tu ◽

Shouzhi Wang ◽

Hehe Jiang ◽

Zhenyan Liang ◽

Dong Shi ◽

...

Keyword(s):

Dielectric Constant ◽

Carbon Fiber ◽

Parallel Plate ◽

Sandwich Structure ◽

High Dielectric Constant ◽

Parallel Plate Capacitor ◽

Plate Capacitor ◽

Fiber Metal ◽

High Dielectric ◽

Mini Plate

The carbon fiber/metal oxide/metal oxynitride layer sandwich structure is constructed in the electrode to form a mini-plate capacitor. High dielectric constant metal oxides act as dielectric to increase their capacitance.

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