scholarly journals The research on precise forming technology of “λ” type composite skin

2021 ◽  
Vol 30 ◽  
pp. 263498332199474
Author(s):  
Qiang Guo ◽  
Kai He ◽  
Hengyuan Xu ◽  
Youyi Wen

With the application of “ λ” type composite skin becoming more and more extensive and diversified, its precise forming technology is also widely concerned. This article mainly solves the quality problems of “ λ” type corner area, such as delamination dispersion and surface wrinkle, which exist in reality commonly in the manufacturing process. The prepreg is heated along the corner area of the tooling to solve the problem that prepreg is difficult to be compacted due to the large modulus of carbon fiber in “ λ” type corner area. Furthermore, two precompaction tests are creatively increased at 16 layers (middle layer) and 32 layers (last layer) for the thick structure, respectively, to ensure the compaction effect of the blank. In addition, combined with the characteristics of highly elastic rubber and carbon fiber-reinforced materials, a new type of soft mold structure with proper flexibility and good stiffness is proposed innovatively through the reasonable placement of carbon fiber-reinforced materials and the setting of exhaust holes according to the structure characteristics of “ λ” type root skin. Through further process verification, it is shown that the improved process has effectively solved the problems of wrinkles and internal delamination at the sharp corners of parts and realized zero-defect manufacturing of “ λ” type root skin for the first time.

2015 ◽  
Vol 723 ◽  
pp. 71-75
Author(s):  
Yong Jun Xia ◽  
Wen Ming Mei ◽  
Yu Jing Hao ◽  
Da Ni

As a special lifting device, the lifting pole is widely used in construction of transmission line powers. Due to the special working environment, a new-type lifting pole made of carbon-fiber reinforced resin matrix composites is designed to facilitate transportation and usage. It is shown by comparison of material properties that new materials can greatly reduce structural self-weight on the condition of ensuring mechanical properties. In order to ensure the equipment is used safely and reliably, this paper carries out mechanical calculation and ANSYS finite element analysis by setting up a mechanical model, and the results show that the design is reasonable and accords with national relevant specifications.


2007 ◽  
Vol 24-25 ◽  
pp. 125-132
Author(s):  
Yong Qi Wang ◽  
Yong Jie Bao ◽  
Hang Gao

Based on the analysis of various disfigurements of carbon fiber reinforced plastics formed in drilling process, the formation model of disfigurement is built up, and analysis results shows that the main reason of disfigurement is the exceeding cutting force. By focusing on these problems, new-type drill—super-hard electroplated abrasive drill is developed, and some experiments were carried out. Compared with the traditional sintered-carbide drill in drilling, the super-hard electroplated abrasive drill has lower drilling force, better drilling quality, higher machining efficiency, and longer life-span. A conclusion that super-hard electroplated drill is more suitable for drilling CFRP is gained.


2019 ◽  
Vol 2 (2) ◽  
pp. 99-104
Author(s):  
Richárd Horváth ◽  
Róbert Gábor Stadler ◽  
Kristóf Andrásfalvy

Abstract The use of fiber-reinforced plastics has increased significantly in the past decades. Consequently, the demand for finishing and machining of such materials has also escalated. During machining, the fiber-reinforced materials exhibit machining problems dissimilar to the problems of metals. These are fiber pull-out, fiber breakage in the cutting zone, matrix smearing and delamination. The purpose of this experiment is to investigate the characteristics of the resultant force (Fe) dur-ing the milling of carbon fiber reinforced plastic as a function of input machining parameters. For the force measurements, CFR with perpendicular (0°-90°) fiber orientation was machined. The experimental design involved the central composite design method. To analyze and evaluate the measurements, we applied the response surface methodology.


2020 ◽  
pp. 002199832097544
Author(s):  
Jie Fei ◽  
Tian Liu ◽  
Lan Luo ◽  
Man Zhou ◽  
Bei Zhao ◽  
...  

To intensify the interfacial properties between carbon fiber (CF) and resin without sacrificing fiber, a new type of carbon fiber reinforced resin composite was designed and fabricated with MnO2 nanosheets and melamine (MA) as interphase. The MnO2 nanosheets were uniformly grown on the carbon fiber via hydrothermal method. And then MA was grafted on the MnO2 nanosheets to from chemical bond with resin by a simple bath shock method. The experiment results show that the flexural and tensile strength of the composite reinforced by CF-MnO2-MA increased by 24.1% and 14.5% compared to that of CF, respectively. And the wear rate is reduced by about 29.6%. In summary, the improvement of mechanical and frictional properties of the composite is related to the synergetic reinforcement in mechanical interlocking and chemical bonding of MnO2 nanosheets and MA.


Author(s):  
Hong-Ming Lin ◽  
C. H. Liu ◽  
R. F. Lee

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.


2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.


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