• Title/Summary/Keyword: CFRP(carbon fiber reinforced plastics)

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The Behavior of Tensile Fracture for Al/CFRP Hybrid Composite Material (Al/CFRP 하이브리드 복합재료의 인장파괴거동)

  • Kang, Ji-Woong;Kwon, Oh-Heon;Ryu, Jin-Gyu
    • Journal of the Korean Society of Safety
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    • v.24 no.2
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    • pp.23-29
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    • 2009
  • The hybrid composite materials are recently used in many field as an advanced material due to their high resistance to fracture. However, hybrid composite materials have several problems, especially delamination, compared with homogeneous materials such as an aluminum alloy, etc. In this study, we carried out the tensile test to study the tension failure appearances and tensile ultimate strength of CFRP/Al/CFRP hybrid composite materials. The CFRP material used in the experiment is a commercial material known as CU175NS in unidirectional carbon prepreg. Also Al/CFRP/Al hybrid composites with three kind length of a single edge crack were investigated for the relationship between an aluminium volume fraction and a crack length. The crack length was measured by a traveling microscope under a universal dynamic tester. Futhermore the stress intensity factor behavior was examined according to a volume fraction and an initial crack length ratio to a width.

On the Machinability of CFRP Composites Dependent on the Number of Stacking and Drill Diameter (CFRP복합재료의 적층수와 드릴직경에 관한 연구)

  • 정성택;박종남;조규재
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.6
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    • pp.8-13
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    • 2003
  • CFRP composite has a lot of merits such as mechanical characteristic, light weight and thermal resistance. For these merits CFRP is applied to so many industrial area. In order for the composite materials to be used in the aircraft structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise machining. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48p1ies specimen with the ${\phi}8$, ${\phi}10$, ${\phi}12mm$ cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

A Study on method of Using Ultrasonic Transducers With shear wave Polarization Direction (전단파 분극현상을 갖는 초음파 탐촉자 민감도 기법에 관한 연구)

  • 나승우;임광희;송상기;정동화;양인영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.744-747
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    • 2001
  • This paper shows shear wave behavior of CFRP composite laminates as a polar grid form to evaluate vibration pattern of ultrasonic transducers, which gives measured modelling fundamental contents of nondestructive evaluation. Polarized direction can be obtained by using a c-scanner and sensitivity of transducers is founded when using through-transmission method of two transducers. And modelling of vector decomposition is presented based on ply-to-ply method to apply practicable nondestructive evaluation of CFRP laminate lay up. This modelling decomposes the transmission of linearly polarized wave into orthogonal components through each ply of a laminate. It is found that a high provable shows between the model and experimental developed in characterizing layup of CFRP composite laminates.

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Drilling Characteristic of CFRP Composites depend on the number of stacking and drill diameter (CFRP복합재료의 적층수와 드릴직경에 따른 가공 특성)

  • 정성택;박종남;조규재
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2003.04a
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    • pp.190-195
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    • 2003
  • CFRP composite has a lot of merits such as mechanical characteristic, light weight, and thermal resistance. For these merits CFRP is applied to so many industrial area. In this paper, the relationship between the stack thickness and drill diameter is examined from the drilling experiment, which is the drilling of 16, 32, 48 plies specimen with the $\phi$8, $\phi$10, $\phi$12mm cemented carbide drill. The results are analyzed with consideration of cutting force, stack thickness and drill diameter.

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Deployment Behaviors of CFRP Reflector under Zero-gravity Environment

  • Chae, Seungho;Oh, Young-Eun;Lee, Soo-Yong;Roh, Jin-Ho
    • International Journal of Aerospace System Engineering
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    • v.7 no.1
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    • pp.1-6
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    • 2020
  • A deployment mechanism is designed to stow into a small volume efficiently. The panels are fabricated by carbon fiber reinforced plastics (CFRPs). The parameters for the deployment are determined by considering the number of panels, the folding/twisting angles, and the driving force for a deployment device. In addition, a surface accuracy of the manufactured reflector is measured through a photogrammetry methodology. The deployment behavior of CFRP reflector is observed by using the zero-gravity device which compensates the gravity effect during the deployment. The zero-gravity device is constructed wire, motor, controller and loadcell. During the deployment of the reflector panel, the wire and motor compensate for its weight by the feedback process of the controller. Tests result show that a zero-gravity device compensates for the weight of the panel during the deployment of the CFRP reflector.

Evaluation of Fracture Toughness of Dynamic Interlaminar for CFRP Laminate Plates by Resin Content (수지함량에 따른 CFRP 적층판의 층간파괴 인성평가)

  • 김지훈;양인영;심재기
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.4
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    • pp.43-49
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    • 2003
  • This research work has been carried out for finding J-integral in mode II of CFRP(carbon fiber reinforced plastics) laminate plates based on the classical bar theory in dynamic conditions with consideration of the effect of inertia forces, eventually to lead to finding the dynamic inter-layer fracture toughness. Dynamic inter-layer fracture toughness was found by a self-made ENF(End Notched Flexure) experimental apparatus using Split Hopkinson's Bar(SHPB), and also observed the variation of the fracture toughness haying different resin contents and fiber arrangements of CFRP specimen([$0_3^{\circ}/90_3^{\circ}/0_6^{\circ}/90_3^{\circ}/0_3^{\circ}$], [$0_{20}^{\circ}$], [$0_5^{\circ}/90_{10}^{\circ}/0_5^{\circ}$]). As an experimental result, in either cases of quasi-static or dynamic load condition, the critical load and the inter-layer fracture toughness increased sharply depending on the increase of resin contents. Therefore, it could, be concluded that the effect by resin contents is the major factor determining the inter-layer fracture toughness in the CFRP laminate plates.

Impact Collapse Behavior of Hybrid Circular Thin-walled Member by Stacking Condition (적층조건에 따른 혼성 원형 박육부재의 충격압궤거동)

  • Lee, Kil-Sung;Park, Eu-Ddeum;Yang, In-Young
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.2
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    • pp.235-240
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    • 2010
  • The recent trend of vehicle design aims at crash safety and environmentally-friendly aspect. For the crash safety aspect, energy absorbing members should be absorbed with collision energy sufficiently. But vehicle structure must be light weight for the environmentally-friendly aspect, in order to improve fuel efficiency and to reduce tail gas emission. Therefore, the light weight of vehicle must be achieved in a status of securing safety of crash. An aluminum or CFRP (Carbon Fiber Reinforced Plastics) is representative one among the light-weight materials. In this study, impact collapse behavior of circular hybrid thin-walled member is evaluated. The hybrid members are manufactured by wrapping CFRP prepreg sheets outside the aluminum circular members in the autoclave. Because the CFRP is an anisotropic material whose mechanical properties change with its stacking condition, special attention is given to the effects of the stacking condition on the collapse behavior evaluation of the hybrid thin-walled member. Collapse mode and energy absorption capability of the hybrid thin-walled member are analyzed with change of the fiber orientation angle and interface number.

Influence of Thickness and Temperature on Delamination Properties of Stitched Carbon Fiber Reinforced Plastics (스티칭 된 탄소섬유 강화 복합소재의 박리 특성에 온도와 두께가 미치는 영향)

  • Yongjun So;Kwak Jin Bae;Han-Gyu Kim;Jaesang Yu
    • Composites Research
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    • v.37 no.5
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    • pp.386-392
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    • 2024
  • Stitching is one of the techniques used to improve the through-thickness properties of CFRPs. In this study, the enhancement of CFRP properties through stitching for aerospace applications was investigated with considering high-temperature conditions and thickness effect. Stitched CFRPs were observed to have 18.2% higher maximum loads and 33.2% higher elastic moduli than non-stitched CFRPs. In addition, as the areas exposed to high temperatures increased, the mechanical properties of the CFRPs decreased regardless of stitching. In thick CFRPs, the load drop rate was complemented by stitching yarn. However, for thin CFRPs, there was no significant change in load drop rate. Additionally, it was observed from testing of the thin CFRPs that multi-layer delamination occurred as the precrack propagation direction changed due to stitching yarns. This study highlights the influence of various factors that need to be considered for the application of CFRPs in the aerospace field, and suggests improving weaknesses by enhancing mechanical properties through stitching. Finally, new perspectives on temperature conditions are presented.

A Study on the Collapse Modes and Energy Absorption Characteristics of AI/CFRP Compound Tubes Under Axial Compression (축 하중을 받는 Al/CFRP 혼성튜브의 압궤모드와 에너지흡수 특성에 관한 연구)

  • Cha, Cheon-Seok;Lee, Kil-Sung;Chung, Jin-Oh;Yang, In-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.11
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    • pp.1768-1775
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    • 2004
  • The compressive axial collapse tests were performed to investigate collapse modes and energy absorption characteristics of Al/CFRP compound tubes which are aluminum tubes wrapped with CFRP(Carbon Fiber Reinforced Plastics) outside the aluminum circular and square tubes. Based on collapse characteristics of aluminum tubes and CFRP tubes respectively, the axial collapse tests were performed for Al/CFRP compound tubes which have different CFRP orientation angles. Test results showed that Al/CFRP compound tubes supplemented the unstable brittle failure of CFRP tubes due to ductile nature of inner aluminum tubes. In the light-weight aspect, specific energy absorption were the highest for Al/CFRP, CFRP in the middle, and aluminum the lowest. Also, specific energy absorption of circular tubes was higher than square tubes'. It turned out that CFRP orientation angle of Al/CFRP compound tubes influence specific energy absorption together with the collapse modes of the tubes.

Bending Performance of Glulam Beams Reinforced with Carbon Fiber-Reinforced Plastics Bonded with Polyvinyl Acetate-Based Adhesive (초산비닐수지계 접착제를 사용한 탄소섬유강화플라스틱 복합집성재의 휨 성능)

  • Park, Jun-Chul;Shin, Yoon-Jong;Hong, Soon-Il
    • Journal of the Korean Wood Science and Technology
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    • v.37 no.4
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    • pp.364-371
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    • 2009
  • This study was carried out to investigate the bending strength of the Larix glulam beams which were reinforced with CFRP (Carbon fiber reinforced plastic) of which the reinforcement ratios were 0.7% and 2.1% by volume. In the bending test, the rupture shape of the reinforced glulam shows that the reinforced glulam broke firstly in the lowest bottom layer on which tension was loaded, but did not in the upper part reinforced with the CFRP layer. The upper part of the reinforced layer kept strength and did not break when the reinforced glulam broke firstly at the bottom part of the reinforced layer, but broke secondly as loading was increased. In the glulam beams reinforced with CFRP of which the reinforcement ratio was 0.7% by volume, the bending strength of the reinforced beams was increased by 28% at the first break. When beams broke up to the upper part of the reinforced layer, the bending strength of the reinforced beams was increased by 55%, compared to those of control glulam beams. When the glulam beams were reinforced with CFRP of which the reinforcement ratio was 2.1% by volume, the bending strength of the reinforced beams was increased by 77%, compared to those of control glulam beams. The ratio of the height of calculated neutral axis using failure mode recommended by Romani and the height of actual neutral axis using strain gauge was 1.03 and agreed well.