• Title, Summary, Keyword: Thin-walled Cylinder

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Determination of Thermal Shock Stress Intensity Factor for Elliptical Crack by Modified Vainshtok Weight Function Method (수정 Vainshtok 가중함수법에 의한 타원균열의 열충격 응력세기계수의 결정)

  • 이강용;김종성
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.2
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    • pp.463-474
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    • 1995
  • Modified Vainshtok weight function method is developed. The thermal shock stress intensity factors for elliptical surface cracks existed in the thin and thick walled cylinders are determined. The present results are compared with previous solutions and shown to be good agreement with them.

Dynamic Analysis of a Rotor System Having Thin-walled Cylinder Combined with Its Shaft (회전축에 Thin-walled Cylinder가 결합된 회전체 시스템의 동적 해석)

  • Choi, Young-Hyu;Park, Seon-Kyun;Hoong, Dae-Sun;Chung, Won-Jee
    • Proceedings of the KSME Conference
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    • pp.631-636
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    • 2000
  • In this paper a transfer method model was introduced in order to analyze critical speeds and vibration modes of a flexible rotor system, whose rotor shaft is cupped into and fitted with a thin-walled cylinder at its end. The computed analysis results were compared with those of the experimental modal test. Both results show good agreement each other. Furthermore the free-run(or run-down) test result for the real rotor system also shows that the proposed transfer matrix method modelling can be successfully applicable to analyzing accurate critical speeds(or natural frequencies) of the rotor system.

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Design of the Brake Device Using the Axial Crushing of Truncated Cone Type Cylinder

  • Kim, Ji-Chul;Shim, Woo-Jeon
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.387-388
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    • 2002
  • A Brake device for the high-speed impacting object is designed using an axial crushing of thin-walled metal cylinder, Thickness of the cylinder is increased smoothly from the impacting end to the fixed end, resulting in the truncated cone shape. Truncated cone shape ensures that plastic hinges are formed sequentially from impacting end. This increases the reliability of brake device working. Computational and real experiments were performed to verify the effects of conical angle. Results indicate that undesirable sudden rise of crushing load can be prevented by applying appropriate conical angle.

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Approximation Method for the Calculation of Stress Intensity Factors for the Semi-elliptical Surface Flaws on Thin-Walled Cylinder

  • Jang Chang-Heui
    • Journal of Mechanical Science and Technology
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    • v.20 no.3
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    • pp.319-328
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    • 2006
  • A simple approximation method for the stress intensity factor at the tip of the axial semielliptical cracks on the cylindrical vessel is developed. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. For these, 3-D finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R=0.1. The approximation solutions are within $\pm2.5%$ of the those of finite element analysis using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the approximation method provides sufficiently accurate stress intensity factor values for the axial semi-elliptical flaws on the surface of the reactor pressure vessel.

Stress Intensity Factor Calculation for the Semi-elliptical Surface Flaws on the Thin-Wall Cylinder using Influence Coefficients (영향계수를 이용한 원통용기 표면결함의 응력확대계수의 계산)

  • Jang, Chang-Heui;Moonn, Ho-Rim;Jeong, Ill-Seok
    • Proceedings of the KSME Conference
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    • pp.280-285
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    • 2001
  • As an integral part of the probabilistic fracture mechanics analysis, stress intensity factor calculation scheme for semi-elliptical surface flaws in thin-walled cylinder has been introduced. The approximation solution utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for cooldown boundary condition. The analysis results confirmed that the simplified methods provided sufficiently accurate stress intensity factor values for axial semi-elliptcal flaws on the surface of the reactor pressure vessel.

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A study on the development of thin-walled metal bearing for the large-sized slow speed diesel engines. (대형저속 디젤엔진용 박판형 메탈 베어링의 국산화 개발에 관한 연구)

  • 김영주;조문제
    • Journal of the Korean Society of Marine Engineering
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    • v.19 no.4
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    • pp.61-71
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    • 1995
  • Nowadays the thin-walled metal bearing, which is made seperately from the bearing housing and has the ratio of wall thickness/bearing diameter being less than 1/30, are used in many newly developed large-sized slow speed diesel engines for the purpose of upgarding lubication performance and easy maintenance according to the trends of increasing output per cylinder and lowering engine speed. The type of this bearing has been used generally in many small-sized high speed engines applied for automobile, high speed craft and industrial power generation systems since 1950s. But the tranditional thick-walled bearings, whice are linned white metal on the bearing housing directly, have been installed on the large and slow speed engines until 1990s due to the easy manufacturing procedures. In this study we have calculated optimum dimensions of the metal bearing, fabricated special zigs for crush measurement, model test machine, 2 sets of specimens.(crosshead pin bearing, $\phi$818*552*20mm) for B & W 6S70MC(20, 940*88rpm), and evaluated metal constact phenomena of white metal, its friction coefficient, temparature rise through the model test and field performance test.

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Bending Behaviors of Stainless Steel Tube Filled with Al5Si4Cu4Mg Closed Cell Aluminum Alloy Foam (발포 Al5Si4Cu4Mg 알루미늄 합금이 충진된 304 스테인리스강 원통의 굽힘저항 특성)

  • Kim, Am-Kee;Lee, Hyo-Jin;Cho, Seong-Seock
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.10
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    • pp.1686-1694
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    • 2003
  • The foam-filled tube beams can be used for the front rail and firewall structures to absorb impact energy during frontal or side collision of vehicles. In the case of side collision where bending is involved in the crushing mechanism, the foam filler would be effective in maintaining progressive crushing of the thin-walled structures so that much impact energy could be absorbed. In this study, bending behaviors of the closed-cell-aluminum-alloy-foam-filled stainless steel tube were investigated. The various foam-filled specimens including piecewise fillers were prepared and tested. The aluminum-alloy-foam filling offered the significant increase of bending resistance. Their suppression of the inward fold formation at the compression flange as well as the multiple propagating folds led to the increase of load carrying capacity of specimens. Moreover, the piecewise foams would provide the easier way to fill the thin-walled shell structures without the drawback of strength.

Design of Energy Absorption Device Using the Axial Crushing Behavior of Truncated Cone Type Cylinder (콘 형상 실린더의 축 방향 압축변형을 이용한 충격흡수장치 설계)

  • 김지철;이학렬;김일수;심우전;박동화
    • Tribology and Lubricants
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    • v.19 no.5
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    • pp.259-267
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    • 2003
  • A brake device for the high-speed impacting object is designed using an axial crushing of thin-walled metal cylinder. Thickness of the cylinder is increased smoothly from the impacting end to the fixed end, resulting in the truncated cone shape. Truncated cone shape minimizes the imperfection-sensitivity of the structure and ensures that plastic hinges are formed sequentially from impacting end. This prevents the undesirable sudden rise in the first peak-crushing load. Several specimens with different conic angles, mean thickness of the wall, and materials were designed and quasi-static compression tests were performed on them. Results indicate that adoption of appropriate conic angle prevents simultaneous wrinkles generation and sudden rise of crushing load and that appropriate conic angle differs in each case, depending on the geometry and material property of the cylinder. Finite element analysis was performed for static compression of the cylinder and its accuracy was checked for the future application.

Manufacture and Bending Behavior of Stainless Steel Cylindrical Shell Filled with Aluminum Alloy Foam (다공성 알루미늄 합금이 충진된 스테인레스 강 원통 Shell의 제조 및 굽힘거동)

  • Kim, Am-Kee;Lee, Hyo-Jin;Cho, Seong-Seock
    • Proceedings of the KSME Conference
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    • pp.19-24
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    • 2003
  • Potential applications of foam-filled section are the automotive structures. A foam-filled section can be used for the front rail and firewall structures to absorb impact energy during frontal or side collision. In the case of side collision where bending is involved in the crushing mechanics, the foam filler will be significant in maintaining progressive crushing of the thin-walled structures so that more impact energy can be absorbed. In this study, the manufacturing process of closed cell aluminum alloy foam filled stainless steel tube was studied, and the various foam filled specimens including piecewise fillers were prepared, tested and discussed about the bending behaviors.

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Interlaminar Normal Stress Effects in Cylindrical Tubular Specimens of Graphite/Epoxy [±45]s Composites

  • An, Deuk Man
    • Composites Research
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    • v.30 no.6
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    • pp.406-409
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    • 2017
  • The thin-walled cylindrical tubes are frequently used for the evaluation of fatigue property of composites. But the curvature of the tubular specimen induces interlaminar normal stress which may affect the fatigue property. In this paper interlaminar normal stress effect on the fatigue behaviour of thin-walled graphite/epoxy tubes $[{\pm}45]_s$ composites was studied experimentally. It was concluded that the interlaminar normal stress induced by the curvature of the cylinder has no discernible effect on the fatigue life. But excessive internal pressure can produce the stiffness increase and this affects the fatigue life of the cylindrical tubular composite.