• 한국전기화학회:학술대회논문집
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• 2005.07a
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• pp.201-206
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• 2005

본 연구는 기 개발 완료된 천연가스차량용 200bar급 Type 3 복합재 압력용기를 개발로 축척된 핵심요소기술과 실질적인 경험을 바탕으로 수소연료전지 차량에 탑재할 350bar급 Type 3 복합재 압력용기에 대한 설계/해석과 시험평가의 핵심적인 사항을 고찰하였다. 설계/해석에는 350bar급 Type 3 복합재 압력용기에 대한 3차원 비선형 유한요소 모델링 및 해석기법이 제시되었고, 설계된 라이너형상과 와인딩 패턴을 이용하여 필라멘트 와인딩 공법으로 1차시제품을 제작하였다. 제작된 시제품에 대하여 파열시험 및 반복피로시험을 수행하여 설계/해석 기법의 타당성을 검증하였다.

• 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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.23-30
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• 2002

Abstract The optimization is performed to reduce the mass of CNG pressure vessel reinforced with composite materials in the hoop direction. An axisymmetric shell element which takes into account the layered liner and hoop composite materials is thus developed and incorporated into a program Axicom. The accuracy of the program is then verified using the 4 noded element in ANSYS. Three different cases of optimization are then performed using the Axicom: (1) uniform hoop thickness, (2) varying hoop thickness, and (3) varying the ply angles and accordingly the thickness. Compared with a traditional method, cases (2) and (3) were found to be very effective in reducing the thickness and cost of the hoop composite materials by about 80% without sacrificing the safety factors.

• Composites Research
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• v.21 no.6
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• pp.23-30
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• 2008

In this paper, the effect of the natural aging on the strength distribution and structural service life of a Filament Wound (FW) composite pressure vessel was studied. The fiber failure strain, which is varied significantly, was considered as the design random variable and the strength analysis was carried out by probabilistic numerical approach. The progressive failure analysis technique and the First Order Reliability Method (FORM) were embedded in this numerical model. As the calculation results, the probability of failure was obtained for each aging time steps and it is found that the strength degradation in FW composite pressure vessel, due to the natural aging, appears within 10 year-aging-time. As an example of the life prediction under natural aging using arbitrary laminated model, the service lifetime of 13 years was predicted based on the probability of failure of 2.5% and the design pressure of 3,250 psi.

• 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.

• 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.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.127-132
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• 2023

In this study, designing of a Type 4 pressure vessel using the filament winding method was conducted. In order to prevent leakage in consideration of the design of the hydrogen storage tank, a liner was designed by applying high-density polyethylene (HDPE), and the composite structure was designed by stacking carbon/epoxy in the hoop and helical directions. As a theoretical approach, the angle of the helical fiber and fiber thickness of each hoop and helix were designed. The safety of the design was verified using the commercial software ANSYS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2741-2749
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• 2010

This paper presents the impact damage behavior of filament wound composite vessels and the effect of surface protective materials on their impact resistance. Using an instrumented impact testing machine, a series of impact tests was performed on the base panels and the protected panels (panels with surface protective materials of rubber, kevlar/epoxy or glass/epoxy laminates) that were cut from the full scale vessel. And the impact damage parameters were used to identify the effect of protective materials on the damage resistance of composite vessels. Damage resistance of the composite vessels was considerably affected by the protective materials regardless of the shape of the indenters. Among the protective materials, glass/epoxy laminates was the most effective mean for improving the damage resistance of composite vessels.

• Journal of the Korean Institute of Gas
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• v.13 no.4
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• pp.15-21
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• 2009

The fiber reinforced composite material is widely used in the multi-industrial field where the weight reduction of the infrastructure is demanded because of their high specific modulus and specific strength. Pressure vessels using this composite material have two main merits which are to cut down energy by reducing weight and to have long-term life due to corrosion resistance. In this paper, we developed optimal design module of laminate for CNG composite pressure vessel winding E-glass/epoxy based on Von-Mises yield criterion, Tsai-Hill theory and stress ratio using finite element method and ANSYS RSM(Response Surface Method).

• Composites Research
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• v.24 no.5
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• pp.1-8
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• 2011

This paper presents the results of theoretical analysis and experimental test to show the size effect on the fiber strength of filament would pressure vessel. First, a series of fully scaled hoop ring tests with filament would carbon-epoxy were conducted, which exhibited a remarkable size effect on the fiber strength. Next, the failure analyses using WWLM(Weibull Weakest Link Model) and the SMFM(Sequential Multi-step Failure Model) were performed and compared to the hoop ring test data, as well as to unidirectional specimens test data from the literature. It was found that the analysis results significantly underestimated the fiber strengths compared to the test data. In this study, a modified SMFM was proposed through the modification of the length size effect. The fiber strengths from modified SMFM analysis showed good agreement with the test data.