scholarly journals Thermal Conductivity of High-Strength Polyethylene Fiber and Applications for Cryogenic Use

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Atsuhiko Yamanaka ◽  
Tomoaki Takao
Keyword(s):  
Thermal Conductivity ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
High Strength ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Cross Sectional ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Polyethylene Fiber

The local temperature rise of the tape is one of instabilities of the conduction-cooled high temperature superconducting (HTS) coils. To prevent the HTS tape from locally raising a temperature, high thermal conductive fiber reinforced plastic was applied to coil bobbin or spacer for heat drain from HTS tape. The thermal conductivity of ramie fibers increases by increasing orientation of molecular chains with drawing in water, and decreases by chain scission with γ-rays irradiation or by bridge points in molecular chains with vapor-phase-formaldehyde treatments. Thermal conductivity of high strength ultra-high-molecular-weight (UHMW) polyethylene (PE) fiber increases lineally in proportion to tensile modulus and decreases by molecular chain scissions with γ-rays irradiation. This result suggested the contribution of the long extended molecular chains due to high molecular weight on the high thermal conductivity of high strength UHMW PE fiber. Thermal conductivity of high strength UHMW PE fiber reinforced plastics in parallel to fiber direction is proportional to the cross sectional ratio of reinforcement oriented in the conduction direction. Heat drain effect of high strength UHMW PE fiber reinforced plastic from HTS tape is higher than that of glass fiber reinforced plastic (GFRP) and lower than that of aluminum nitride (AlN). In the case of HTS coil, the thermal stability wound on coil bobbin made of high strength UHMW PE fiber reinforced plastic is good as that of AlN, and better than that of GFRP.

The radiation effect on thermal conductivity of high strength ultra-high-molecular-weight polyethylene fiber by γ-rays

2006 ◽  
Vol 101 (4) ◽  
pp. 2619-2626 ◽  
Author(s):  
Atsuhiko Yamanaka ◽  
Yoshinobu Izumi ◽  
Tooru Kitagawa ◽  
Takaya Terada ◽  
Hideki Sugihara ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Radiation Effect ◽  
High Strength ◽  
Polyethylene Fiber ◽  
Γ Rays ◽  
Ultra High Molecular Weight

scholarly journals Comparison of Mode Shapes of Carbon-Fiber-Reinforced Plastic Material Considering Carbon Fiber Direction

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 311
Author(s):  
Chan-Jung Kim
Keyword(s):  
Carbon Fiber ◽  
Modal Analysis ◽  
Dynamic Behavior ◽  
Mode Shapes ◽  
Modal Parameters ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Direction ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic

Previous studies have demonstrated the sensitivity of the dynamic behavior of carbon-fiber-reinforced plastic (CFRP) material over the carbon fiber direction by performing uniaxial excitation tests on a simple specimen. However, the variations in modal parameters (damping coefficient and resonance frequency) over the direction of carbon fiber have been partially explained in previous studies because all modal parameters have only been calculated using the representative summed frequency response function without modal analysis. In this study, the dynamic behavior of CFRP specimens was identified from experimental modal analysis and compared five CFRP specimens (carbon fiber direction: 0°, 30°, 45°, 60°, and 90°) and an isotropic SCS13A specimen using the modal assurance criterion. The first four modes were derived from the SCS13A specimen; they were used as reference modes after verifying with the analysis results from a finite element model. Most of the four mode shapes were found in all CFRP specimens, and the similarity increased when the carbon fiber direction was more than 45°. The anisotropic nature was dominant in three cases of carbon fiber, from 0° to 45°, and the most sensitive case was found in Specimen #3.

Restraint of Voids Generated Inside Injection Molded Products by In-Mold Pressing Method

2018 ◽  
Vol 12 (6) ◽  
pp. 930-939 ◽  
Author(s):  
Atsushi Motegi ◽  
Tomohiro Hishida ◽  
Yasuhiko Murata ◽  
◽  
Keyword(s):  
Injection Molding ◽  
High Strength ◽  
Compression Molding ◽  
Fiber Reinforced ◽  
Pressing Method ◽  
Glass Fiber Reinforced Plastic ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Injection Molded ◽  
Injection Compression Molding

In recent years, long glass fiber reinforced plastic and carbon fiber reinforced plastic have begun to be used for structural components that require high strength. As a result, thick-walled injection molded products are being manufactured. However, defects, known as voids, are generated inside the molded product and decrease the strength of the molded product, posing a significant problem at molding production sites. The partial compression method, which is a type of injection compression molding, is effective in preventing voids in thick-walled injection molding. However, there have been limited studies that comprehensively investigated the effects of the compression conditions on void prevention in thick-walled injection molding products or the shape and dimension of the molded product, or the issues in the molded product produced by applying compression. The authors have previously proposed the in-mold pressing (IMP) method, which allows the application of partial compression without the use of an injection compression molding machine and verified its validity. In this study, we proposed a compression device in which a servomotor-driven hydraulic pump actuator is used to propel a movable rod to apply compression to the melt inside the mold cavity. The IMP method using this device was applied to mold thick-walled products with thicknesses of 10 mm and greater, and the effects of compression on the generation of voids inside the molded product and the shape and dimensions of the product were investigated. The results indicate that the generation of voids can be prevented by application of this method. In addition, it was found that marginal deformations, which can pose issues, occur in the molded product when compressive stresses generated inside the molded product by compression are released after demolding.

Face Milling of Carbon Fiber Reinforced Plastic Using Poly Crystalline Diamond Tool

2014 ◽  
Vol 1017 ◽  
pp. 383-388 ◽  
Author(s):  
Jumpei Kusuyama ◽  
Akinori Yui ◽  
Takayuki Kitajima ◽  
Yosuke Itoh
Keyword(s):  
Carbon Fiber ◽  
High Strength ◽  
Face Milling ◽  
Hole Drilling ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced ◽  
Poly Crystalline Diamond

Carbon Fiber Reinforced Plastic (CFRP) is a high-strength and high-elastic-modulus composite material that is hardened by impregning carbon fiber with epoxy resin. Although, many sutdies of hole drilling of CFRP have been conducted, few sutdies of face milling of CFRP have been carried out. Face milling is necessary for surfaceing of aerospace parts, which is indispensable for airplane construction. Machining of CFRP is difficult because of the extreme tool wear and delamination that occur. The authors investigated face milling of CFRP using a newly developed Poly Crystalline Diamond (PCD) tool. The resultts show, that the cutting force and surface roughness are affected by the fiber orientation of the CFRP, and that delamination can easily occur in the outer layer of face-nilled CFRP.

Experimental Research on Interlaminal Shear Strength of GFRP Bridge Decks under Simulated Concrete Environment

2012 ◽  
Vol 525-526 ◽  
pp. 249-252
Author(s):  
Wei Chen Xue ◽  
Kai Fu
Keyword(s):  
Shear Strength ◽  
Bridge Deck ◽  
Bridge Decks ◽  
High Strength ◽  
Sample Surface ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Plastic ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Shear Strength Degradation

Fiber reinforced plastic (FRP) composite which has high strength, high fatigue resistance, low density, and better corrosion resistances is desirable characteristics for bridge applications, especially decks. According to the ACI 440.3R04, Glass fiber reinforced plastic (GFRP) bridge deck samples were immersed into the simulated concrete environment at 60 for 92d (corresponds to the natural environment 25 years). The results show that, with the time increased, the interlaminal shear strength of GFRP bridge decks decreased significantly. After being exposed to the simulated concrete environment for 3.65d, 18d, 36.5d and 92d, the interlaminal shear strength degradation of GFRP bridge decks were 18.69%, 25.90%, 50.93% and 53.74%, respectively. The micro-formation of the GFRP bridge deck sample surface was surveyed under scanning electron microscopy (SEM), which indicated that with the aging time increased, corrosion pits in the surface of GFRP bridge decks became more obviously and the interface between fiber and resin was severely damaged. Therefore, the degradation of FRP under the simulated concrete environment should be considered in the design of FRP bridge decks.

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