• Title/Summary/Keyword: 복합재압력용기

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Test Method to Evaluate the Fiber Material Properties of Filament Wound Composite Pressure Vessel (필라멘트 와인딩 복합재 압력용기의 섬유 방향 물성 평가 기법)

  • Hwang, Tae-Kyung;Park, Jae-Beom;Kim, Hyoung-Geun
    • Composites Research
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    • v.23 no.3
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    • pp.37-42
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    • 2010
  • The fiber material properties, elastic constant and strength, are the most important factors among the various material properties for the design of composite pressure vessel, because of it's dominant influence on the performance of composite pressure vessel. That is, the deformation and burst pressure of pressure vessel highly affected by the fiber material properties. Therefore, the establishment of test method for exact fiber material properties is a priority item to design a composite pressure vessel. However, the fiber material properties in filament wound pressure vessel is very sensitive on various processing variables (equipment, operator and environmental condition etc..) and size effect, so that it isn't possible to measure exact fiber material properties from existing test methods. The hydro-burst test with full scale pressure vessel is a best method to obtain fiber material properties, but it requires a enormous cost. Thus, this paper suggests a newly developed test method, hoop ring test, that is capable of pressure testing with ring specimens extracted from real composite pressure vessel. The fiber material properties from hoop ring test method showed good agreement with the results of hydro-burst test with full scale composite pressure vessels.

Evaluation of the Residual Strength of CFRP Composite Pressure Vessel After Low Velocity Impact (CFRP 복합재압력용기의 충격후 잔류강도저하특성 평가)

  • Park, Jae-Beom;Kim, Dong-Ryun;Hwang, Tae-Kyung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.439-442
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    • 2009
  • In this study, the residual strength of CFRP filament winding pressure vessel after low velocity impact was evaluated quantitatively. After impact test, the pressure vessel was sectioned to produce 25 mm-wide ring specimen and the bursting pressure of this specimen was measured. A finite element model was also fabricated to investigate the deformation and stress distribution characteristics of the impacted CFRP vessel. The degradation of the residual strength along with the increase of impact energy was successfully measured and reviewed.

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음향방출을 이용한 복합재 연소관의 건전성 평가

  • 이상호;최용규
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1997.11a
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    • pp.32-32
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    • 1997
  • 복합재 연소관의 구조적 건전성 평가 방법을 개발하기 위하여 표준 평가용 시편의 수압 시험 중, 연소관으로부터 방출되는 음향방출(acoustic emission: AE) 신호를 측정 장비를 이용하여 신호 처리함으로써 시편이 파괴되기 전, 대략적인 시편의 파열 위치 및 일정 압력 유지상태에서 hit rate 양상에 의한 건전성 평가 방법을 제시하였다. 데이터의 분석 기법 향상을 위하여 음향방출 데이터를 시간 및 센서별로 분류하는 프로그램을 개발하였다. 수압 시험을 낮은 압력 단계부터 높은 압력 단계까지 일정 압력 유지 상태(load-hold)에서 발생한 hit 수와 1분간 유지한 후 발생되는 hit rate(hit/sec)의 값의 크고 작음이 복합재 압력 용기의 결함수의 증감으로 나타났으며, 이로부터 복합재 압력 용기의 파열 압력과의 상관관계 및 건전성을 예측할 수 있었다. 복합재 압력 용기의 파열 위치는 energy rate(energy/sec) 측정값을 분석하여 예측하였으며, 파열 압력의 30∼50%에서 가능하였다.

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A Study on the Skirt Size Selection of a Composite Pressure Vessel using Optimum Analysis Technique (최적화 해석 기법을 이용한 복합재 압력용기의 스커트 치수 선정에 관한 연구)

  • Kim, Jun-Hwan;Jeon, Kwang-Woo;Shin, Kwang-Bok;Hwang, Tae-Kyung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.403-407
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    • 2012
  • The purpose of this study is to find the optimum skirt size for a composite pressure vessel using optimum analysis technique. The size optimization for skirt shape of a composite pressure vessel was conducted using sub-problem approximation method and batch processing codes programmed by APDL(ANSYS Parametric Design Language). The thickness and length of skirt part were selected as design variables for the optimum analysis. The objective function and constraints were chosen as weight and displacement of skirt part, respectively. The numerical results showed that the weight of skirt of a composite pressure vessel would be saved by maximum 4.38% through the size optimization analysis for the skirt shape.

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Probabilistic Fiber Strength of Composite Pressure Vessel (복합재 압력용기의 확률 섬유 강도)

  • 황태경;홍창선;김천곤
    • Composites Research
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    • v.16 no.6
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    • pp.1-9
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    • 2003
  • In this paper, probabilistic failure analysis based on Weibull distribution function is proposed to predict the fiber strength of composite pressure vessel. And, experimental tests were performed using fiber strand specimens, unidirectional laminate specimens and composite pressure vessels to confirm the volumetric size effect on the fiber strength. As an analytical method, the Weibull weakest link model and the sequential multi-step failure model are considered and mutually compared. The volumetric size effect shows the clearly observed tendency towards fiber strength degradation with increasing stressed volume. Good agreement of fiber strength distribution was shown between test data and predicted results for unidirectional laminate and hoop ply in pressure vessel. The site effect on fiber strength depends on material and processing factors, the reduction of fiber strength due to the stressed volume shows different values according to the variation of material and processing conditions.

Evaluation of Residual Strength of CFRP Pressure Vessel After Low Velocity Impact (저속 충격 하중을 받은 탄소섬유강화 복합재 압력용기의 잔류강도 저하 평가)

  • Park, Jae-Beom;Kim, Dong-Ryun;Kim, Hyung-Geun;Hwang, Tae-Kyung
    • Composites Research
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    • v.21 no.3
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    • pp.9-17
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    • 2008
  • In this paper, the low velocity impact characteristics of filament winding CFRP pressure vessel was investigated using numerical and experimental methods. The cylinder part of CFRP vessel was impacted using triangular shape impactor which simulated the sharp edge of dropping tools and impact response behavior of CFRP was reviewed. The mechanical behavior, such as deformation and stress distribution, were also predicted by explicit finite element method and the validity of the model was investigated. For the quantitative evaluation of the residual strength of the pressure vessel after impact, a series of the ring specimens was cut from the impacted vessel and its burst pressure was measured by hydraulic pressure hoop tension test. As the results, the relationship between the residual strength degradation and the impact energy was successively obtained and a useful methodology to evaluate quantitatively the impact damage tolerance of CFRP pressure vessel was established.

The Structural Integrity Evaluation of Composite Pressure Vessel Using Acoustic Emission (음향방출을 이용한 복합재 압력용기의 건전성 평가)

  • 이상호;최용규
    • Journal of the Korean Society of Propulsion Engineers
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    • v.1 no.2
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    • pp.1-11
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    • 1997
  • During hydroproof test of composite pressure vessel, acoustic emission signal was measured and analyzed to evaluate structural integrity of composite motor case. When pressure was held for 1 min. at constant pressure from low pressure level to high pressure level, the pattern of hit rate of good composite pressure vessel is increased with higher value than that of bad composite pressure vessel. This report also presents detection possibility of burst location approximately in the range of 25∼36% of burst pressure using energy rate. In case that it is difficult to detect burst location of composite motor case, it is possible to detect burst location, i.e. structurally weak location of composite pressure vessel with applying same pressure lower than maximum expected operating pressure(MEOP) repeatedly.

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A Study on Improving Fatigue Life for Composite Cylinder with Seamless Integrated Liner (이음매 없는 일체형 라이너를 갖는 복합재 압력용기의 피로수명 향상에 대한 연구)

  • Kim, Hyo-Joon
    • Journal of the Korean Institute of Gas
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    • v.17 no.6
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    • pp.46-51
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    • 2013
  • Composite cylinder is used by hydrogen fuel cell vehicles and natural gas vehicles because of high specific modulus, specific strength and fatigue resistance. composite cylinder has a seamless integrated liner and it is fully overwrapped with structural fibers of high strength carbon fibers in an epoxy matrix. In this study, filament winding pattern and autofrettage pressure design technique are presented considering structural weakness of knuckle and compressive residual stress. Presented methodology is verified by pressure cycling test of composite cylinders.

The Prediction of Structural Behavior for Composite Pressure Vessel with Changed Dome Shape (돔 형상 변화에 따른 복합재 압력용기의 구조 거동 예측)

  • Hwang, Tae-Kyung;Park, Jae-Byum;Kim, Hyung-Kun;Doh, Young-Dae
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.288-292
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    • 2008
  • Dome shape design method of filament wound (FW) composite pressure vessel, which can create various dome shape with fixed boss opening, was suggested. And, the performance indices (PV/W) for composite pressure vessel with same boss opening but different dome shape were investigated by finite element analysis (FEA) and hydro-test. The FEA showed good agreement with test results for burst pressure. Generally, as the dome shape of pressure vessel was changed to flat dome, the inner volume is increased and the burst pressure is decreased. In the case of above ${\rho}_o$=0.54, the performance index showed decreased value due to the low burst pressure. However, at ${\rho}_o$=0.35, the dome shape change brings not significant reduction of burst pressure and performance index.

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Cycling life prediction method considering compressive residual stress on liner for the filament-wound composite cylinders with metal liner (금속재 라이너를 갖는 복합재 압력용기의 라이너 압축잔류응력을 고려한 반복수명 예측 방법에 대한 연구)

  • Park, Ji-Sang;Jeung, Sang-Su;Chung, Jae-Han
    • Composites Research
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    • v.19 no.1
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    • pp.22-28
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    • 2006
  • In manufacturing process of composite cylinders with metal liner, the autofrettage process which induces compressive residual stress on the liner to improve cycling life can be applied. In this study, a finite element analysis technique is presented, which can predict accurately the compressive residual stress on the liner induced by autofrettage and stress behavior after. Material and geometrical non-linearity is considered in the finite element analysis, and the Von-Mises stress of a liner is introduced as a key parameter that determines pressure cycling life of composite cylinders. Presented methodology is verified through fatigue test of liner material and pressure cycling test of composite cylinders.