• Title/Summary/Keyword: Thin Cylinder

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Two-dimensional Stress Analysis Using Boundary Element Method (경계요소법(境界要素法)에 의한 2차원(次元) 응력해석(應力解析))

  • Chang-Doo,Jang;Sung-Hoon,Lee
    • Bulletin of the Society of Naval Architects of Korea
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    • v.23 no.4
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    • pp.11-18
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    • 1986
  • The fundamental theory and application of boundary element method for two-dimensional problem are introduced in this paper. Based on this boundary element procedure, several numerical calculations such as circular cavity problem, a thin plate with hole under tension and a long thick-walled cylinder under internal pressure are performed. The numerical results show fairly good agreement with exact solutions or results of finite element method.

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A Study of Hear Flux and Instantaneous Temperature According to the Initial Tamperature of Combustion Chamber in a Constant Volume Combustion Chamber (연소실 초기온도 변화에 따른 순간열유속에 관한 연구)

  • Lee, Chi-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.6 no.3
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    • pp.193-200
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    • 2003
  • In the production of internal combustion engines, there has been a move towards the development of high performance engines with improved fuel efficiency, lighter weight and smaller sizes. These trends help to answer problems in engines related to thermal load and abnormal combustion. In order to investigate these problems, a thin film-type probe for instantaneously measuring temperatures has been suggested. A method for manufacturing such a probe was established in this study. The instantaneous surface temperature of a constant volume combustion chamber was measured by this probe and the heat flux was obtained through Fourier analysis. In order to thoroughly understand the characteristics of combustion, the authors measured the wall temperature of the combustion chamber and computed heat flux through a cylinder wall while varying the protrusion height of the probe. For achieving the above goals, a instantaneous temperature probe was developed, thereby making possible the analysis of the instantaneous temperature of wall surface and the detection of unsteady heat flux in the constant volume combustion chamber.

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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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    • 2003.04a
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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.

Effect of Manufacturing Condition on the Physical Properties of TTD Yarns with Hot Plate Device (Hot Plate장치를 이용한 TTD사 제조조건에 따른 사의 물성변화 연구)

  • Song, Min-Kyu;Kim, Hi-Dong;Kwon, Oh-Kyung
    • Fashion & Textile Research Journal
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    • v.7 no.2
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    • pp.247-251
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    • 2005
  • In this the study, the effects of the manufacturing process conditions on the properties Thick and Thin Diameter yarns(TTD yarns) prepared with hot plate device in the draw winder were determined. Physical properties including wet shrinkage, tenacity and elongation of the samples were measured and thick and thin effect was analysed with the evenness tester. The results were as the follows: There was little change the wet shrinkage of the TTD yarns in the range of $70^{\circ}C{\sim}80^{\circ}C$ of $R_1$ temperature(lower hot cylinder) with the same Hot Plate(H/P) temperature, but the wet shrinkage of the TTD yarns decreased 5-10% when $R_1$ temperature was $90^{\circ}C$. The wet shrinkage of the TTD yarns decreased with the H/P temperature at the same temperature of $R_1$. There was little effect of $R_1$ and H/P temperature on the tenacity of TTD yarns. The elongation of TTD yarns increased with $R_1$ temperature at the same H/P temperature. The elongation of TTD yarns increased little bit for the first time and then decreased above that temperature with increasing H/P temperature at the same $R_1$ temperature. The thick and thin effect on the TTD yarns was obvious in $110^{\circ}C$ of H/P temperature regardless of $R_1$ temperature, while there was no thick and thin effect on the TTD yarns in $140^{\circ}C$ of H/P temperature.

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.

Analytical similitudes applied to thin cylindrical shells

  • De Rosa, Sergio;Franco, Francesco
    • Advances in aircraft and spacecraft science
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    • v.2 no.4
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    • pp.403-425
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    • 2015
  • This work is focused on the definition and the analysis of both complete and incomplete similitudes for the dynamic responses of thin shells. Previous numerical and experimental investigations on both structural and structural-acoustic systems motivated this further analysis, mainly centred on the incomplete (distorted) similitudes. These similitudes and the associated scaling laws are defined by using the classical modal approach (CMA) and by invoking also the Energy Distribution Approach (EDA) in order to take into account both the cinematic and energetic items. The whole procedure is named SAMSARA: Similitude and Asymptotic Models for Structural-Acoustic Research and Applications. A brief summary of the procedure is herein given and the attention is paid to the analytical models of thin stiffened and unstiffened cylindrical shells. By using the well-known smeared model, the stiffened cylinder equations are used as general framework to analyse the possibility to define exact (replicas) or distorted similitudes (avatars). Despite the extreme simplicity of the proposed models, the results are really encouraging. The final aim is to define equivalent models to be used in laboratory measurements.

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 Advanced Marine Engineering and Technology
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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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Stress Intensity factor Calculation for the Axial Semi-Elliptical Surface Flaws on the Thin-Wall Cylinder Using Influence Coefficients (영향계수를 이용한 원통용기 축방향 표면결함의 응력확대계수의 계산)

  • Jang, Chang-Heui;Moon, Ho-Rim;Jeong, Ill-Seok;Kim, Tae-Ryong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.11
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    • pp.2390-2398
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    • 2002
  • For integrity analysis of nuclear reactor pressure vessel, including the Pressurized thermal shock analysis, the fast and accurate calculation of the stress intensity factor at the crack tip is needed. For this, a simple approximation scheme is developed and the resulting stress intensity factors for axial semi-elliptical cracks in cylindrical vessel under various loading conditions are compared with those of the finite element method and other approximation methods, such as Raju-Newman's equation and ASME Sec. Xl approach. For these, three-dimensional finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R = 0.1. 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 clement analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. The approximation solutions are within $\pm$2.5% of the those of FEA 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 VINTIN method provides sufficiently accurate stress intensity factor values for axial semi-elliptical flaws on the surface of the reactor pressure vessel.

Nondestructive Buckling Load Prediction of Pressurized Unstiffened Metallic Cylinder Using Vibration Correlation Technique (Vibration Correlation Technique을 이용한 내부 압력을 받는 금속재 단순 원통 구조의 비파괴적 전역 좌굴 하중 예측)

  • Jeon, Min-Hyeok;Kong, Seung-Taek;Cho, Hyun-Jun;Kim, In-Gul;Park, Jae-Sang;Yoo, Joon-Tae;Yoon, Yeoung-Ha
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.50 no.2
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    • pp.75-82
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    • 2022
  • Nondestructive method to predict buckling load for the propellant tank of launch vehicle should be evaluated. Vibration correlation technique can predict the global buckling load of unstiffened cylindrical structure with geometric initial imperfection using correlation of natural frequency and compressive load from compressive test below the buckling load. In this study, vibration and buckling tests of a thin metal unstiffened propellant tank model subjected to internal pressure and compressive loads were performed and the test results were used for VCT to predict global buckling load. For the vibration test of thin structure, non-contact excitation method using a speaker was used. The response was measured with piezoelectric polymer(PVDF) sensor. Prediction results of VCT were compared with the measured buckling load in the test and the nondestructive global buckling load prediction method was verified.