• Title/Summary/Keyword: CFRP (Carbon Fiber Reinforced Plastic)

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Test Results of Composite Cylinder Surface Temperature change between Pool Fire and Single Impinging Jet Flame Exposure Condition (전체 화염 및 단일 화염 노출 조건에서 복합재료 용기 표면 온도 변화 비교)

  • Lee, Jae-Hun;Hwang, Jun-Ho;Kim, Young-Seop;Kim, Hyo
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.648-651
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    • 2009
  • 탄소섬유강화플라스틱(CFRP:Carbon Fiber Reinforced Plastic)용기의 외부에 화재가 발생할 경우 함침된 수지(Resin)가 탄화되면서 자체 강도가 약화되고 충전된 가스가 외부 온도 상승에 따라 압력 상승이 발생하여 용기의 폭발로 이어지는 사고가 발생할 개연성이 높다. 화염 노출조건에서 복합재료 용기의 폭발을 방지하기 위하여 용기용 밸브에 내장된 온도감응식 압력안전장치(TPRD:Thermally activated Pressure Relief Device) 작동 성능을 검증하기 위한 방법으로 화염실험(Bonfire test)를 실시하고 있으나, 개방 공간에서 실시되는 이 실험은 표면 온도 변화가 매우 크게 발생하여 실험에 대한 재현성(Reproducibility)에 의문이 제기되고 있다. 따라서, 표면 온도를 일정하게 유지하기 위한 실험 방법의 개선이 필요하다. 본 연구에서는 경유+heptane을 이용한 전체 화염에 노출되는 경우와, 천연가스를 이용한 단일화염에 노출되는 경우의 실험 결과 비교를 통하여 화염 노출 표면 온도를 일정하게 유지하기 위한 가열 방법의 타당성을 검토하였다. 또한, 복합재료 라이너(Liner)의 온도 변화 비교를 통하여 집중화염 노출 조건에서 열전달 특성을 알아보았다.

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A Study on Vibration Intensity of Laminated Composite Plate (복합적층판의 진동인텐시티에 관한 연구)

  • Seo, Jin;Kim, Dong-Young;Hong, Do-Kwan;Choi, Seok-Chang;An, Chan-Woo;Han, Geun-Jo
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.892-895
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    • 2002
  • In this study, to grasp the effect of vibration intensity fur the laminated composite plate, the two-dimension plate was shaken by a harmonic point excitation with the natural frequency using the finite element method. As the result, it shows that the vibration intensity according to the change of angle-ply is various and it flows to the direction of length rather than width in the plate. Also this paper represents those results to the vector flow.

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A Study on the Vibration Analysis for the Composite Multi-axial Optical Structure of an Aircraft (항공기용 복합재료 다축 광학 구조의 진동해석에 관한 연구)

  • Kim, Dae-Young;Kwak, Jae-Hyuck;Lee, Jun-Ho;Park, Kwang-Woo;Jeong, Kwang-Young;Cheon, Seong-Sik
    • Composites Research
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    • v.24 no.2
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    • pp.14-21
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    • 2011
  • In this paper, a dynamic model is proposed for multi-axis optical structure of an aircraft. Modal analysis, sine-wave analysis, and random vibration analysis are done using a multi-body dynamic program for the multi-axis optical structure. By applying Al 6061-T6 and two types of CFRP to the camera module, x, y, and z responses are found and compared according to each axis excitation. The results will be used for reducing the weight of the camera module.

Improvement of Out-of-Plane Impact Damage Resistance of CFRP Due to Through-the-Thickness Stitching

  • Yoshimura, Akinori;Nakao, Tomoaki;Takeda, Nobuo
    • Advanced Composite Materials
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    • v.18 no.2
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    • pp.121-134
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    • 2009
  • The present study investigated, both experimentally and numerically, the improvement of low-velocity impact damage resistance of carbon fiber reinforced plastic (CFRP) laminates due to through-the-thickness stitching. First, we conducted drop-weight impact tests for stitched and unstitched laminates. The results of damage inspection confirmed that stitching did improve the impact damage resistance, and revealed that the improvement effect became greater as the impact energy increased. Moreover, the stitching affected the through-the-thickness damage distribution. Next, we performed FEM analysis and calculated the energy release rate of the delamination crack using the virtual crack closure technique (VCCT). The numerical results revealed that the stitching affected the through-the-thickness damage distribution because the stitch threads had a marked effect on decreasing both the modes I and II energy release rate around the bottom of the laminate. Comparison of the results for models that contained delaminations of various sizes revealed that the energy release rate became lower as delamination size increased; therefore the stitching improved the impact resistance more effectively when the impact energy was higher.

Design of Flexible Composite Propellers considering Fluid-structure Interaction (유체-구조 연성 효과를 고려한 복합소재 유연 프로펠러의 설계)

  • Kim, Ji-Hye;Ahn, Byoung-Kwon;Kim, Gun-Do
    • Journal of the Society of Naval Architects of Korea
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    • v.57 no.2
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    • pp.61-69
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    • 2020
  • Due to its flexibility of the composite propeller blade, it is necessary to design a shape capable of generating a desired load at a design point in consideration of the shape change of the propeller. In order to design it, we need to evaluate not only the hydrodynamic force around it, but also its structural response of flexible propeller according to its deformation. So, it is necessary to develop a design tool to predict the hydroelastic performance of a flexible propeller with deformation considering fluid-structure interaction and special operating conditions. Finally a design optimization tool for flexible propellermade of CFRP is required. In this study, a design methodology of the specific flexible composite propeller is suggested, considering fluid-structural interaction analysis of the specific flexible propeller.

High-cycle fatigue characteristics of quasi-isotropic CFRP laminates

  • Hosoi, Atsushi;Arao, Yoshihiko;Karasawa, Hirokazu;Kawada, Hiroyuki
    • Advanced Composite Materials
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    • v.16 no.2
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    • pp.151-166
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    • 2007
  • High-cycle fatigue characteristics of quasi-isotropic carbon fiber reinforced plastic (CFRP) laminates [-45/0/45/90]s up to $10^8$ cycles were investigated. To assess the fatigue behavior in the high-cycle region, fatigue tests were conducted at a frequency of 100 Hz, since it is difficult to investigate the fatigue characteristics in high-cycle at 5 Hz. Then, the damage behavior of the specimen was observed with a microscope, soft X-ray photography and a 3D ultrasonic inspection system. In this study, to evaluate quantitative characteristics of both transverse crack propagation and delamination growth in the high-cycle region, the energy release rate associated with damage growth in the width direction was calculated. Transverse crack propagation and delamination growth in the width direction were evaluated based on a modified Paris law approach. The results revealed that transverse crack propagation delayed under the test conditions of less than ${\sigma}_{max}/{\sigma}_b$ = 0.3 of the applied stress level.

On Clamping Force Characteristics in M1.4 Subminiature Screw for CFRP Stacking Angles (M1.4 초소형 나사의 CFRP 적층 경향에 따른 체결력 특성에 관한 연구)

  • Kim, Jung Ho;Ra, Seung Woo;Kim, Hee Seong;Kim, Ji Hoon
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.6
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    • pp.517-521
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    • 2015
  • Recent development of core techniques the IT electronics industry can condense into lightweight and slimmer. In this circumstance, researches for the lightweight materials and subminiature screw have been attracted. In this study, the CFRP was produced by stacking angle to obtain the tensile properties. And Comparing the coated screws and non-coated screws on the specimen, and evaluating the adequacy for the application of CFRP using the result. So The clamping force measured by comparison evaluation. Low screw reverse and Superior torque value at each stacking angle were found the optimum conditions, when Subminiature Screw is applied on smart devices. Both tensile strength and stiffness of $[{\pm}0^{\circ}]_{10}$ is the highest. Followed by $[90^{\circ}/0^{\circ}]_{10}$ is the highest. The largest clamping torque is $[90^{\circ}/0^{\circ}]_{10}$ When Subminiature Screw is applied coating and non-coating to prevent loosening. Based on the above, Subminiature Screw should be applied in smart devices, because $[90^{\circ}/0^{\circ}]_{10}$ meet both tensile properties and clamping force.

Evaluation of the Impact Behavior of Inline Disk Wheel Made of Carbon Fiber Reinforced Composites (탄소섬유 강화 복합재로 구성된 인라인 디스크 휠의 충격거동 평가)

  • Kwon, Hye-In;Lee, Sang-Jin;Shin, Kwang-Bok
    • Composites Research
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    • v.29 no.2
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    • pp.73-78
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    • 2016
  • In this paper, The concept of a wheel with carbon fiber composite is to replace the conventional material used for a wheel hub, such as plastic, with a disk-type hub made of carbon fabric and epoxy resin. The impact load from the ground under real conditions was considered; a low-velocity impact test was conducted to evaluate the impact performance of the carbon wheel and compare it with that of a conventional plastic wheel. This study applied a 70 J impact load as a test condition. The impact energy was controlled in the test by adjustment of height and weight of impactor. The use of a carbon disk wheel hub was confirmed to reduce weight and generate an excellent repulsive force at low energy under conditions similar to real driving conditions. The results showed that the maximum load increased proportionally depending on the impact load, but the growth of the maximum load was reduced at a 20 J impact load and tended to decrease at a 45 J impact load. The carbon wheel showed excellent properties ; the level of rebounding was 35.3% and 19.1% of the total impact energy at impact loads of 5 J and 10 J, respectively. On the other hand, the carbon disk wheel rebounded less than 5% of the total energy due to crack generation of the thin carbon hub for impact loads of more than 20 J.

Design and Structural Safety Evaluation of 1MW Class Tidal Current Turbine Blade applied Composite Materials (복합재료를 적용한 1MW급 조류 발전 터빈 블레이드의 설계와 구조 안전성 평가)

  • Haechang Jeong;Min-seon Choi;Changjo Yang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.7
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    • pp.1222-1230
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    • 2022
  • The rotor blade is an important component of a tidal stream turbine and is affected by a large thrust force and load due to the high density of seawater. Therefore, the performance must be secured through the geometrical and structural design of the blade and the blade structural safety to which the composite material is applied. In this study, a 1 MW class large turbine blade was designed using the blade element momentum (BEM) theory. GFRP is a fiber-reinforced plastic used for turbine blade materials. A sandwich structure was applied with CFRP to lay-up the blade cross-section. In addition, to evaluate structural safety according to flow variations, static load analysis within the linear elasticity range was performed using the fluid-structure interactive (FSI) method. Structural safety was evaluated by analyzing tip deflection, strain, and failure index of the blade due to bending moment. As a result, Model-B was able to reduce blade tip deflection and weight. In addition, safety could be secured by indicating that the failure index, inverse reserve factor (IRF), was 1 or less in all load ranges excluding 3.0*Vr of Model-A. In the future, structural safety will be evaluated by applying various failure theories and redesigning the laminated pattern as well as the change of blade material.

Study on Mechanical Properties of CFRP Composite Orthogonal Grid Structure (CFRP 복합재료 직교 격자 구조의 기계적 특성 연구)

  • Baek, Sang Min;Lim, Sung June;Kim, Min Sung;Ko, Myung Gyun;Park, Chan Yik
    • Composites Research
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    • v.31 no.2
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    • pp.69-75
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    • 2018
  • In this study, a grid panel structure in which the woven CFRP composites were stacked in the orthogonal array was proposed and the mechanical properties were analyzed and studied. The grid parts were fabricated by cutting prepregs and laminating them. The grid panel structure was fabricated by co-curing with lower laminate plate in auto-clave process. The behavior of the proposed grid panel structure was evaluated by tests under tensile, compressive, shear, and bending loads. The effect of increasing the stiffness of the orthogonal grid structure was verified through these tests. In addition, the finite element model was constructed and compared with the test results, confirming the validity and reliability of the test and analysis.