• Title, Summary, Keyword: carbon material

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The Vibration Characteristic of Carbon-Carbon Composite Material due to Tensile Loading (인장하중에 따른 Carbon/Carbon복합재의 진동특성)

  • Oh, Seung-Gyu;Kwac, Lee-Ku;Kim, Hong-Gun
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.20 no.6
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    • pp.740-744
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    • 2011
  • Carbon-carbon composite material is the reinforced carbon fiber. Because of its high strength, elasticity and the excellent heat-resisting property in high temperature, carbon-carbon composite material has been used in many fields such as aerospace and automotive industries, etc. Especially, aircraft brake discs used at aerospace can be cracked due to its fatigue and vibration under various loading condition. This research is focused on the influence of the vibration of carbon-carbon composite material by using accelerometer with impact hammer excitation. And the change of vibration mode will be known by applying tensile loading test.

A Study on Ultrasonic Evaluation of Material Defects in Carbon/carbon Composites

  • Im, Kwang-Hee;David K. Hsu;Cha, Cheon-Seok;Sim, Jae-Ki;Yang, In-Young
    • Journal of Mechanical Science and Technology
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    • v.16 no.12
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    • pp.1652-1663
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    • 2002
  • It is desirable to perform nondestructive evaluation to assess material properties and part homogeneity because manufacturing of carbon/carbon (C/C) composites requires complicated and costly processes. In this work several ultrasonic techniques were applied to carbon/carbon composites for the evaluation of spatial variations in material properties that are attributable to the manufacturing process. In a large carbon/carbon composite manufactured by chemical vapor infiltration (CVI) method, the spatial variation of ultrasonic velocity was measured and found to be consistent with the densification behavior in CVI process in order to increase the density of C/C composites. Ultrasonic velocity and attenuation depend on a density variation of materials. Low frequency through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity These results were compared with that obtained by dry-coupling ultrasonics. Pulse-echo C-scans was used to image near-surface material property anomalies such as the placement of spacers between disks during CVI. Also, optical micrograph had been examined on the surface of C/C composites using a destructive way.

Performance of the Negative Carbon Electrode Prepared with Graphitic Carbon and Nongraphitic Carbon Material in Lithium Ion Secondary Battery (흑연계 및 비흑연계 탄소로 조합된 리튬이온 이차전지의 탄소부극 특성)

  • Kim, Hyun-Joong;Lee, Chul-Tae
    • Applied Chemistry for Engineering
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    • v.9 no.7
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    • pp.1065-1069
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    • 1998
  • This study was investigated to improve peformance of carbon negative electrode for lithium ion secondary battery. The carbon electrode was prepared by mixing with graphitic carbon material, natural graphite, and nongraphitic carbon material, petroleum cokes, which was heat-treated at $700^{\circ}C$ for l hour. Its electrochemical and charge-discharge characteristics were tested according to mixing ratio of different two types of carbon material. The carbon electrode prepared with various mixing ratio showed both charateristcs of two different types of carbon materials and the best characteristics as carbon electrode was demonstrated at mixing ratio of 1:1.

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Challenges in Carbon/Carbon Composites Technologies

  • Dhami, T.L.;Bahl, O.P.
    • Carbon letters
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    • v.6 no.3
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    • pp.148-157
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    • 2005
  • Carbon/Carbon Composites due to their far superior thermo-mechanical properties are used in a number of demanding applications. However, the material still is used only in specific high tech applications with few exceptions in general industrial applications. The material is extremely expensive and the major challenge is to reduce its cost. Various innovative processing routes are outlined to reduce the cost of processing.

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Multiscale Stress Analysis of Palladium/Carbon Fiber Composites for the Hydrogen High Pressure Vessel (수소고압저장용기용 팔라듐 첨가 탄소섬유복합재에 대한 멀티스케일 응력해석)

  • Park, Woo Rim;Kwon, Oh Heon
    • Journal of the Korean Society of Safety
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    • v.33 no.2
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    • pp.1-7
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    • 2018
  • The multi-scale analysis is more proper and precise for composite materials because of considering the individual microscopic structure and properties of each material for composite materials. The purpose of this study is to verify the validity of using palladium particles in carbon/fiber composites by multi-scale analysis. The palladium is a material for itself to detect leaking hydrogen by using the property of adsorbing hydrogen. The macroscopic model material properties used in this study are homogeneous material properties from microstructure. Homogenized material properties that are calculated from periodic boundary conditions in the microscopic representative volume element model of each macroscopic analysis model. In this study, three macroscopic models were used : carbon fiber/epoxy, carbon fiber/palladium, palladium/epoxy. As a result, adding palladium to carbon/epoxy composite is not a problem in terms of strength.

Carbon Medicine in Ancient China

  • Yang, Hongyan;Fu, Zengxiang;Huang, Xingli;Ma, Binrui
    • Carbon letters
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    • v.6 no.4
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    • pp.255-256
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    • 2005
  • In traditional Chinese medicine, some herbs are used after toasting or roasting. The process is called "Zhi Tan" in Chinese, which means charring, and the herbs after the treatment is called carbon medicine. Carbon medicine is widely used to arrest bleeding in traditional Chinese medicine. The paper introduces the records, development and applications of carbon medicine in ancient China. The earliest record found about carbon medicine was in the remains of Han dynasty (BC206-A.D.8). The paper also introduces the process of charring herbs and mechanism of carbon medicine in arresting bleeding. Calcium iron and tan released during the charring are believed as main factors for arresting bleeding, helped with porous surface structure of active carbon.

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Formation and Dispersion Measurement in Semiconducting Materials Using the SEM and AFM (SEM과 AFM을 사용한 반도전 재료 내 카본블랙의 형태 및 분산성 측정)

  • Lee, Kyoung-Yong;Yang, Jong-Seok;Nam, Jong-Chul;Choi, Yong-Sung;Park, Dong-Ha;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.236-237
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    • 2005
  • To measure surface roughness and smoothness of semiconducting materials in power cable, we have investigated the formation and growth process of carbon black showed by changing the content of carbon black. The specimens were primarily kneaded in material samples of pellet form for 5 minutes on rollers ranging between 70[$^{\circ}C$] and 100[$^{\circ}C$]. Then they were produced as sheets after pressing for 20 minutes at 180[$^{\circ}C$] with a pressure of 200[kg/cm]. The contents of conductive carbon black were the variable, and their contents were 20, 30 and 40[wt%], respectively. The surface roughness and smoothness of specimens were measured by SEM and AFM. From SEM experimental result, carbon black in specimens formed matrix as a particles. Also we showed growth process of carbon black according to an increment of the content of carbon black. From AFM experimental result, surface roughness of specimens decreased according to an increment of the content of carbon black.

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Optimal Shape Design of ANG Fuel Vessel Applied to Composite Carbon Fiber (탄소섬유 복합재료를 적용한 ANG 연료용기의 최적 형상설계)

  • Kim, Gun-Hoi
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.1
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    • pp.65-71
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    • 2019
  • The development of adsorbed natural gas (ANG) has emerged as one of potential solutions. It is desirable to reduce the weight of vessel by applying light-weighed a composite carbon fiber in order to response to a egulation of $CO_2$ emission. Through understanding of a composite carbon fiber, and material characteristic of a composite carbon fiber is required in order for better application of a reduction of weight and an analysis of material characteristic. Herein, this study suggest the composite carbon fiber vessel applied to the characteristic of carbon fiber, and it decides the preliminary shape based on the test of material characteristic for ANG vessel applied to a composite carbon fiber, and its basic shape calculate through on the netting theory. Moreover, the detail shape design is analyzed by a finite element analysis, and in the stage of detail sahp design and analysis of stress was performed on the typical shape using a finite element analysis, and the result of preliminary design was verified.