• Title/Summary/Keyword: Stress Ring

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A Study on the Evaluation Method for optimal Tensile NOL Ring Composite Specimen Manufactured by Filament Winding Process-to manufacture and elvaluate the composite turbine blade of wind generator system- (필라멘트 와인딩 공법으로 제조된 복합재료 NOL Ring 시험편의 최적 인장강도의 평가법에 관한 연구 -풍력발전용 복합재료 터빈블레이드 제조 및 평가를 목적으로-)

  • 배창원;권순철;임철문;엄수현;김윤해
    • Journal of Advanced Marine Engineering and Technology
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    • v.25 no.1
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    • pp.87-94
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    • 2001
  • Filament winding process is a comparatively simple operation in which continuous reinforcements in the form of roving are wound over a rotating mandrel. And now it is well established as a versatile method for storage tanks and pipe for the chemical and other industries. In this study, tensile strength of a filament wound ring specimens were evaluated by split disk test fixture and dress disk test fixture. The results obtained from experiments were compared with the theoretical values obtained by the rule of mixture. And the purpose of this paper is to suggest an appropriate test method for the evaluation of tensile properties of filament wound structures. The tensile strength of a ring specimens tested by the dress disk test showed better agreement with the theoretical values than of a ring specimen tested by the split disk test because the stress concentration in edges of s split disk test fixture is more severe than the that of dress disk test fixture. The results showed that the tensile strength of a ring specimen was influenced by the geometry of test fixture, the continuity of fibers, fiber-tension, fiber-end and stress concentration in specimen.

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A Study on Contact Characteristics of Mechanical Face Seals for a Hydro-power Turbine Depending on the Rubbing Surface Geometry (소수력 터빈용 기계평면시일의 표면마찰형상에 따른 접촉특성 해석에관한 연구)

  • Kim Chung-Kyun
    • Tribology and Lubricants
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    • v.22 no.3
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    • pp.119-126
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    • 2006
  • In this paper, the contact behavior characteristics of a primary sealing components such as a seal ring and a seal seat has been presented for a small hydro-power turbine. Using the non-linear FEM analysis, the maximum temperature, the axial displacement, radial differences between a seal ring and a seal seat, and maximum contact normal stress have been analyzed for three optimized sealing profiles in which are designed based on the FEM analysis and Taguchi's experimental method. The three primary sealing profiles between a seal ring and a seal seat are strongly related to a leakage of a water for a hydro-power turbine and wear of a primary sealing component. The computed results show that the contact rubbing area between a seal ring and a seal seat is very important for reducing a friction heating and wear in a sealing gap, and increasing a contact normal stress in primary sealing components. Based on the FEM computation, models II and III in which have a small rubbing surface of seal rings show low dilatation of primary sealing components, and high normal contact stress between a seal ring and a seal seat. Thus, the FEM computed results recommend a short contacting width of a primary sealing component for reducing a leakage and thermal distortions, and expanding a seal life. This means that a conventional primary sealing component may be switched to a reduced sealing face of seal rings.

Optimization Design on the Sealing Surface Profiles of Contacting Seal Units (접촉식 시일장치의 밀봉 접촉면 형상에 대한 최적화 설계연구)

  • Kim, Chung-Kyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.6
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    • pp.761-766
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    • 2011
  • In this study, the optimized design profiles between a seal ring and a seal seat of contacting seal units has been proposed based on the FEM computed results. The maximum temperatures, the thermal distortions in axial and radial directions, and maximum contact normal stresses between a seal ring and a seal seat have been analyzed for various contact sealing profiles. The FEM computed results present that the contact area between seal rings and seal seats is very important for a good tribological performance such as low friction heating, low wear, high contact normal stress in a primary sealing components. The seal surface model III in which has a small sealing contact area shows low dilatation of primary sealing components, and high contact stress between a seal ring and a seal seat. This model with small contact surface of a seal ring produces high friction heating and contact stress. But the model III produces very small deformations of contacting sealing surface because of high convection heat transfer by cooling water circulation around the seal ring surface. Thus, the analysis results recommend a short width of a primary sealing unit rather than a big width of contact surfaces of contacting seal units for reducing a leakage and axial deformation of primary seal components.

A Study on the Optimum Evaluation Method for Tensile NOL Ring Specimen Manufactured by Filament Winding Process (Filament winding에 의해 제조된 복합재료 NOL RING시험편의 최적 인장강도 평가법에 관한 연구)

  • 권순철;임철문;배창원;엄수현;김윤해
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.11a
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    • pp.203-207
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    • 2000
  • Filament Winding Process is a comparatively simple operation in which continuous reinforcements in the form of roving are wound over a rotating mandrel. And now well established as a versatile method for storage tanks and pipe for the chemical and other industries . In this study, tensile strength of a filament wound ring specimens were evaluated by split disk test fixture and dress disk test fixture , The results obtained from experiments were compared with the theoretical values obtained by the rule of mixtures. And the purpose of this paper is the suggestion of an appropriate test method for the evaluation of tensile properties of filament wound structures .The tensile strength of a ring specimen tested by the dress disk test showed better agreement with the theoretical values than of a ring specimen tested by the split disk test because the stress concentration in edges of a split disk test fixture is more severe than that of dress disk test fixture. The results showed that the tensile strength of a ring specimen was influenced by the geometry of test fixture, the continuity of fibers, fiber-tension, fiber-end and stress concentration in specimen.

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A Study on the Sealing Characteristics of Multi-contact O-rings (다접오링의 밀봉특성 해석에 관한 연구)

  • Kim, Chung Kyun
    • Journal of the Korean Institute of Gas
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    • v.16 no.5
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    • pp.52-57
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    • 2012
  • This study presents sealing characteristics of multi-contact o-rings as functions of strain, compression stress, and contact normal stress using a FEM technique. The FEM results on the sealing characteristics show that the maximum strain, maximum compression stress, and maximum contact normal stress of multi-contact o-rings are approximately 1.7 times higher than those of conventional o-rings. This is due to a U-grooved cross section of multi-contact o-rings, and the multi-contact o-rings with a U-groove show more effective in sealing for high pressure vessels, valves, and gas equipments. And the extrusion failure in the multi- contact o-ring does not produce for an increased gas pressure due to a U-groove. This may extend sealing life compared to that of a conventional o-ring.

A study on the cross-section profile of the seal ring in the stern tube sealing system (선미관 밀봉 장치 시일링의 단면 형상에 관한 연구)

  • 남정길
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.35 no.1
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    • pp.50-53
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    • 1999
  • In this paper, the mechanical movement of lip seal-ring which plays the most important function in stern-tube sealing system and the possibility of leakage caused by pressure fluctuation are studied by theory and experiment. By the finite element method for axial symmetry object which receives the torsional bending load, the displacement and stress analysis of the seal-rings are executed for products of several representative manufacturers of seal-rings, and also the possibility of crack occurance are checked by theoretical analysis. A sample seal-ring id designed and manufactured using the program of displacement and stress analysis developed in this study and made an experimental apparatus to test the sampling seal-ring. The sampling seal-ring functioned excellently, but it had its durability and this problem may be solved by using the Viton instead of NBR.

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Ultimate Strength Analysis of Ring-stiffened Cylinders Using Commercial Softwares(II) (상용소프트웨어를 이용한 원환보강 원통의 최종강도 해석(II))

  • 박치모;이승훈
    • Journal of Ocean Engineering and Technology
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    • v.16 no.1
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    • pp.36-40
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    • 2002
  • Despite the frequent use of ring-stiffened cylinders as a submarine pressure hull or members of various types of offshore structure, their ultimate strength analysis methods have not been well established because of their complex structural characteristics. This paper has established the method how to use commercial softwares based on the finite element method to implement the ultimate strength analysis of ring-stiffened cylinders covering both types of initial imperfection, i.e. initial deformation and initial stress by combining two separately offered functions of common commercial finite element softwares, linear elastic buckling analysis and nonlinear stress analysis. Developed method was applied to one of the world-widely used commercial softwares. ABAQUS for the analysis of ring stiffened cylinders. This paper ends with some useful information about the imperfection sensitivity of ultimate strength ring stiffened cylinders.

Ultimate Strength Analysis of Ring-stiffened Cylinders Using Commercial Softwares(II) (상용소프트웨어를 이용한 원환보강 원통의 최종강도 해석(II))

  • 박치모;이승훈
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.114-118
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    • 2001
  • Despite the frequent use of ring-stiffened cylinders as a submarine pressure hull or members of various types of offshore sutructures, their ultimate strength analysis methods have not been well established because of their complex structural characteristics. This paper has established the method how to use commercial softwares based on the finite element method to implement the ultimate strength analysis of ring-stiffened cylinders covering both types of initial imperfections, I. e. initial deformation and initial stress by combining two separately offered functions of common commercial finite element softwares, linear elastic buckling analysis and nonlinear stress analysis. Developed method was applied to one of the world-widely used commercial softwares, ABAQUS for the analysis of ring-stiffened cylinders. This paper ends with some useful information about the imperfection sensitivity of ultimate strength of ring-stiffened cylinders.

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The effect of peak cladding temperature occurring during interim-dry storage on transport-induced cladding embrittlement

  • Kim, Kyu-Tae
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1486-1494
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    • 2020
  • To evaluate transport-induced cladding embrittlement after interim-dry storage, ring compression tests were carried out at room temperature(RT) and 135 ℃. The ring compression test specimens were prepared by simulating the interim-dry storage conditions that include four peak cladding temperatures of 250, 300, 350 and 400 ℃, two tensile hoop stresses of 80 and 100 MPa, two hydrogen contents of 250 and 500 wt.ppm-H and a cooling rate of 0.3 ℃/min. Radial hydride fractions of the ring specimens vary depending on those interim-dry storage conditions. The RT compression tests generated lower offset strains than the 135 ℃ ones. In addition, the RT and 135 ℃ compression tests indicate that a higher peak cladding temperature, a higher tensile hoop stress and the lower hydrogen content generated a lower offset strain. Based on the embrittlement criterion of 2.0% offset strain, an allowable peak temperature during the interim-dry storage may be proposed to be less than 350 ℃ under the tensile hoop stress of 80 MPa at the terminal cool-down temperature of 135 ℃.

Heterogeneous overexpression of Oryza sativa salt induced RING Finger protein OsSIRF1 positively regulates salt and osmotic stress in transgenic Arabidopsis

  • Chapagain, Sandeep;Jang, Cheol Seong
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.150-150
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    • 2017
  • Plants suffer from various abiotic stresses among them; soil salinity is one of major adverse factor in declining agricultural productivity. So, development of salt stress tolerance crops have potential role to increase crop production. The RING finger proteins are known to play crucial roles in abiotic stress environment to plants. In this study, we identified one Salt-responsive Really${\underline{I}nteresting}$ ${\underline{n}ew}$ ${\underline{g}ene}$ (RING) E3 ubiquitin ligase gene OsSIRF1 from rice root tissues during salt stress and studied its molecular function. Expression of OsSIRF1 was induced under various abiotic stress conditions, including salt, heat, drought, and ABA. Result of an in vitro ubiquitination assay clearly showed that OsSIRF1 Possess an E3 ligase activity. Moreover, OsSIRF1 was found to be localized to the nucleus within the cell. Heterogeneous overexpression of OsSIRF1 in Arabidopsis improved seed germination and increased root length under salt and Manitol stress conditions. Taking together, these results suggested that OsSIRF1 may be associated with plant responses to abiotic stressors and positively regulates salt and osmotic stress environment.

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