• Title/Summary/Keyword: Tube sinking

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A Study on the Tube Sinking Process of the Industrial Boiler Tube (산업용 보일러 Tube의 Sinking 공정에 관한 연구)

  • Kwon, I.K.;Kang, K.P.;Lee, W.J.
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.94-99
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    • 2001
  • Theoretical analysis using finite element method are peformed in order to clarify the formation of the flare-shape defect for multi-step tube sinking process. The parameters of concern were the friction between the tube and the die, and geometrical parameters, such as the die inclination angle, the diameters of the die entrance and exit, and the curvature at the corner of the die exit. The effect of the curvature at the comer of the die exit is dominant for determining the flare-shape defect. In order to minimize the flare-shape defect the curvature at the corner of the die exit should be increased up to a certain level(120mm). Using three-step tube sinking die sets which have different curvatures at the comer of the die exit, several numbers of tests were performed and its results are compared with that of theoretical analysis.

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Comparison of Energy Consumptions for Various Forming Processes (성형 가공 차이에 의한 에너지 소비량 비교)

  • Yin, Z.H.;Zhang, Y.J.;Chae, M.S.;Park, B.C.;Kim, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.333-336
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    • 2008
  • There are many different kinds of forming processes to make a tubular product such as hydroforming and tube drawing. However, we should consider a better forming process in view point of energy consumption and $CO_2$ emission to save our earth. In this paper we have conducted FEM simulations to the various forming processes for sheet and tubular products to compare their energy consumptions. One example is tubular product and the other for drawn cup. From the comparisons of total energy for hydrofroming and tube sinking processes, hydroforming is consumed more energy than tube drawing. Also the cup drawing from sheet metal and tube sinking for the cup with flange indicate that the tube sinking is better than cup drawing of sheet metal in energy consumption.

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An Upper Bound Solution of Tube Drawing (관인발의 상계해석)

  • 엄경근;이동녕
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.03b
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    • pp.40-47
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    • 1996
  • An upper bound solution of tube drawing process using a fixed tapered plug has been obtained , which reduces to an solution for tube sinking by setting friction factor between tube and plug at zero. Effects of various process paraments have been discussed based on the solution.

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The Study on the Development of Boats Applied to Skill to Prevent Sinking (침몰 방지형 단정 개발에 관한 연구)

  • Park, Jong-Beom;Lee, Dong-Hun;Kim, Deok-Eun;Kim, Soo-Young
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.1 s.145
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    • pp.128-133
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    • 2006
  • This study is focused on the skill to prevent RIB (Rigid Inflatable Boat) from sinking. For better ability to prevent sinking, single hypalon tube is replaced by double TPU (Thermoplastic Polyurethane) tube that is excellent at frictional wear strength and oil-resisting qualities. High buoyant materials are arranged in empty spaces of ship so that ship's spare buoyancy is increased. And for restoration of stable position of ship, the self-righting system is installed. Aluminium alloy is used for increasing hull strength.

Analysis of Deformation of Brass Tube Drawn By Various Methods (인발 방법에 따른 황동관의 변형 해석)

  • ;Oh Kyu Hwan;Lee Dong Nyung
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.10a
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    • pp.76-85
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    • 1995
  • The general equation of homogeneous strin for tube drawing has been derived. This can be applied to the general tube drawing method for non-zero plug angle. Also, the derived equation can represent Blazynski's equations for the sinking and tube drawing with a constant plug diameter. The general tube drawing was divided into two steps, sinking and contact drawing zones. The derived equation can calculate the homogeneous strains of the two steps. The various tube drawing methods such as fixed tapered plug, fixed mandrel, fixed back tapered plug, and floating plug have been analysed by the equation and finite element analysis. From the FEM calculations, the total strains and drawing stresses are obtained and consequently the redundancy factor of various drawing methods was analysed. The fixed back tapered plug method showed the largest redundancy factor and the floating plug method had the largest drawing stress.

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A study on the process of tube end spinning by the upper bound method and the finite element method (상계해법과 유한요소법을 이용한 스피닝공정 해석에 관한 연구)

  • 김전형;홍성인;이정환;이영선
    • Transactions of Materials Processing
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    • v.6 no.6
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    • pp.517-526
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    • 1997
  • The purpose of this study is to investigate changes in the wall thickness of tube sinking and working forces by the upper bound method and ABAQUS code. The independent variables are ; workpiece material, original wall thickness of tube, die angle, friction, and reduction of diameter. The results indicate that these five variables are factors of the increase in wall-thickness and working forces. Three variables, a inner tube wall angle and two angles of the velocity discontinuous surfaces, are optimized in this proposed velocity field by the upper bound method. In this method, we can estimate the working forces and final tube thicknesses similar to actual forming process. Optimum process variables which are obtained by upper bound method are used in ABAQUS pre-model.

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A Study on the Process of Tube End Spining by the Upper bound Method and Finite Element Method (상계해법과 유한요소법을 이용한 스피닝공정 해석에 관한 연구)

  • 김진형;홍성인;이영선
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.03b
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    • pp.23-30
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    • 1996
  • The purpose of this study was to investigate changes in thewall thickness of tube sinking and working forces by the upper bound method and ABAQUS code. The independent variables were : Workpiece material, original wall thickness of tube, die angle, friction, and diameter reduction. The results indicated that of these five variables were a factor in wall-thickness increase and working forces. Three variables, a inner tube wall angle and two angles of the velocity discontinuous surfaces, are optimized in this proposed velocity field by the upper bound method. In this method, we can estimate the working forces and final tube thicknesses whcih are similar to acturla forming process. Optimized process variables which are obtained by upper bound method are used in ABAQUS pre-model . In ABAQUS analysis, the stress and the strain contours which are considered to be heat generation occured by the friction during forming process are observed.

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A Time-temperature Indicator for A Vision Based-Detection System for Managing the Storage Temperature of Frozen Fish Products (냉동 수산물의 저장 온도 관리를 위한 Time-temperature Indicator와 비전 기반 Indicator 분석 프로그램 개발)

  • Jang, Myung-Kee;Hong, Chang-Wook;Choi, Jae-Hyuk;Kim, Koth-Bong-Woo-Ri;Choi, Jeong-Wook;Nam, Taek-Jeong;Ahn, Dong-Hyun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.1
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    • pp.91-94
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    • 2018
  • We develop a time-temperature indicator (TTI) that can determine whether thawing of fish and other fishery products has occurred during frozen storage. A polypropylene tube with an internal diameter of 3 mm was prepared and cut to a length of 14 to 20 mm. One end of the tube was thermally sealed and 0.1% acetic acid was injected into the other end; the tube was then frozen at $20^{\circ}C$. Then the open side of the frozen tube was blocked by sinking the tube into a 10% gelatin solution. The tube was attached to a polyvinyl packaging bag along blue litmus paper and the bag was put into a freezer at $-20^{\circ}C$. After freezing, the bag was removed to an ambient temperature of $20^{\circ}C$, and the time dependence of the color change of the litmus paper was observed. The color changed from blue to red, with the length of the red region increasing with time. Our TTI can be used as a part of a visible detection system and the detection program can conduct the elapsed time analysis on the length of the red region of the litmus paper indicating the degree of thawing. Thus, the TTI is a useful tool in the temperature management of frozen fish and fishery products.

Shearing Conditions on the Interface of a Spherical Water Drop Sinking in Silicone Oil

  • Uemura, Tomomasa;Yamauchi, Makoto
    • Journal of Mechanical Science and Technology
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    • v.15 no.12
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    • pp.1845-1852
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    • 2001
  • This paper deals with the experiment to obtain quantitative information about conditions of the interface between a water drop and surrounding oil. Velocity distributions in very close region of the interface are measured by introducing a new illumination technique and a telecentric lens. It enables precise measurements of velocity distributions in the close region to the interface. Although the measured velocity distributions exhibit strong influence from the solid wall of an experimental tube, the coincidence of inner and outside velocities on the interface is clearly confirmed for the clean interface. The shearing stresses on the interface, which are proportional to the velocity gradient normal to the interface, clearly show conditions of contaminated interface, which can be divided into two parts. From front stagnation point to somewhere near a separation point, the distribution of shearing stresses is well coincide with that of the Hadamard's analytical solution, while the distribution on the latter part of the interface sows quite different feature, which is supposed to be strongly influenced by contamination of the surface.

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Interpretation on the Four-Properties of the Traditional Korean Drugs by the Effects on the Autonomic Nervous System (자율신경계를 통한 한약약성의 해석)

  • Kim, Ho-Cheol;Park, Chan-Woong
    • The Journal of Korean Medicine
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    • v.18 no.2
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    • pp.148-154
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    • 1997
  • In the pharmacology of traditional Korean medicine, each drug has its own specific characters. The different characters of drugs are employed to treat diseases, rectify the hyperactivity or hypoactivity of yin or yang, and help the body restore its normal physiological functions, consequently curing the diseases and restoring health. The various characters and functions of these drugs concerning medical treatment include drugs' properties, flavours, actions of lifting, lowering, floating and sinking, channel tropism, toxicity, etc. Among these theories, theory of properties and flavours of drugs provides the basis for drug analysis and application. 'Property' refers to the cold, hot, warm or cool nature of a drug. These properties of drugs are so sorted out according to the different actions of the drugs on the human body and thier therapeutic effects. Drugs which cure heat syndrome(yang syndrome) have a cold or cool property, whereas drugs which cure cold syndrome (yin syndrome) have hot or warm property Drugs of cold and cool-natured and drugs of warm and hot natures are of opposite properties. A cold-natured drug is different from a cool-natured on only in degree, and so is a warm-natured drug from a hot-natured drug. Most of the cool- or cold- natured drugs have the effects of clearing heat, purging fire, removing toxic substances, and nourishing yin, and are uese to cure heat syndromes. On the contrary, drugs of warm or hot nature usually have the effects of dispersing cold, warming up the interior, supporting yang, and treating collapse, and are therefore used to treat cold syndromes. We thought that the property of drug may be related to the autonomic nervous system in western medicine. In other words, drugs of warm or hot nature increase heart rate or acts like sympathomimetics, and drugs of cool or cold nature decrease heart rate or acts like para sympathomimetics . According to this hypothesis, we administrated some drugs to isolated rat right atrium in magnus tube. But there is no correlation between 'property' in traditional Korean medicine and autonomic nervous system in western medicine.

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