• Title/Summary/Keyword: transverse pressure

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Estimation of buckling and collapse behaviour for continuous stiffened plate under combined transverse axial compression and lateral pressure (조합하중을 받는 연속보강판의 좌굴 및 붕괴거동 평가)

  • Park, Joo-Shin;Choi, Joung-Hwan;Hong, Kwan-Young;Lee, Gyoung-Woo
    • Journal of Navigation and Port Research
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    • v.33 no.1
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    • pp.27-33
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    • 2009
  • Estimation of the buckling and ultimate strength of a continuous stiffened plate subjected to combined transverse compression and lateral pressure is of high importance to ensure the safety of ship structures, particularly for the bottom plating under a deep draft condition For example, bottom plating of bulk carriers is subjected to transverse thrust caused by the bending of double bottom structure and the direct action of pressure on the side shells. Most of experimental tests, theoretical approach and numerical researches have been performed on the buckling and ultimate strength behaviour of plates or stiffened plates under combined compression and lateral pressure. With regard to stiffened panels, however, most of studies have been concerned with the load conditions of combined longitudinal thrust and lateral pressure, while fewer studies have been performed for the combined transverse thrust and lateral pressure. In addition, the previous researches are mainly concerned with an isolated rectangular plate simply supported along the all edges, whereas actual ship plating is continuous across the transverse frames and heavy girders. In the present paper, a series of elastoplastic large deflection FEA on a continuous stiffened plate is performed and then clarify the characteristic of collapse mode and explain the effect of transverse compression.

MHD Pressure Drop of a Liquid-Metal Flow under a Transverse Magnetic Field (자기장하의 액체금속 유동의 차압 측정)

  • Cha, Jae-Eun;Kim, Hee-Reyoung;Kim, Jong-Man;Nam, Ho-Yoon;Kim, Sung-O;Kim, Byung-Ho
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2638-2641
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    • 2007
  • The magnetohydrodynamic(MHD) pressure drop along a liquid sodium flow was measured in a rectangular duct under a transverse magnetic field. The test section was made of a 3 mm thick stainless steel SUS304 with a $74{\times}5mm^2$ rectangular flow channel. The range of experimental parameters was roughly B=0${\sim}$0.18T and U=0${\sim}$0.9m/s at around $200^{\circ}C$. The differential pressure was measured by a diaphragm seal-type pressure transmitter filled with a high temperature silicon oil within 0.1MPa. The experimental results show a similar pressure drop with the theoretical estimation according to a change of the flow velocity and the magnetic field.

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Pressure Analyses at the Planar Surface of Liquid-Vapor Argon by a Test-Area Molecular Dynamics Simulation

  • Lee, Song-Hi
    • Bulletin of the Korean Chemical Society
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    • v.33 no.9
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    • pp.3039-3042
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    • 2012
  • Pressure tensors at the planar surface of liquid-vapor argon are evaluated from the virial theorem, Irving-Kirkwood, and Harasima versions using a test-area molecular dynamics simulation method through a Lennard-Jones intermolecular potential at two temperatures. We found that the normal and transverse components of the pressure tensor, $p_N(z)$ and $p_T(z)$, obtained from the virial theorem and Harasima version are essentially the same. The normal component of the pressure tensor from Irving-Kirkwood version, $p_N^{IK}(z)$, is shown to be a nearly constant at the lower temperature, independent of z, as agreed in a previous study, but not for $p_N^H$(z), while the transverse components, $p_T^{IK}(z)$ and $p_T^H(z)$, are almost the same. The values of surface tension for both versions computed from $p_N(z)-p_T(z)$ are also the same and are fully consistent with the experimental data.

Effects of Abdominal Drawing-in using Pressure Biofeedback Training on Pain, Performance of Transverse Abdominis, Oswestry Disability Index, and Quality of Life in Postpartum Women: Targeted at Women in their 30s Less than One Year Postpartum (압력 생체 되먹임 훈련을 이용한 복부 드로잉 운동이 산후 여성에서 통증, 배가로근 수행력, 요통장애지수, 삶의 질에 미치는 효과: 출산 후 1년 미만의 30대 여성을 대상으로)

  • Hyoung-bong Song;Geun-hong Park;Eun-bi Kim;Tae-won Kim;Sung-doo Park
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.30 no.1
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    • pp.1-13
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    • 2024
  • Background: The purpose of this study was to investigate the effects of stabilization exercise performed after abdominal drawing exercise using pressure biofeedback for 8 weeks on pain level, performance of transverse abdominis, back pain disability index, and quality of life in women in their 30s less than one year after giving birth. Methods: A total of 20 women who voluntarily participated less than one year after giving birth were randomly divided into a control group and an experimental group. The control group was subjected to abdominal drawing exercise before lumbar stabilization exercise, and the experimental group was subjected to abdominal drawing exercise using pressure biofeedback before lumbar stabilization exercise thrice a week for eight weeks. The quadruple visual analog scale (QVAS), the performance of transverse abdominis, the Korean version of the Oswestry disability index (KDOI), the inventory of functional status after childbirth (IFSAC), and the Short Form-12 item (SF-12) were evaluated before and after the intervention. Results: Except for the Physical Components Summary Scale of SF-12, after the intervention, the experimental group showed significant improvement in QVAS, performance of Transverse abdominis , KDOI, and Mental Components Summary Scale of SF-12 compared to the control group. Conclusion: Selective deep muscle activation through abdominal drawing exercises using pressure biofeedback can help rehabilitation for women after postpartum.

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Fracture Toughness Embrittlement by Hydride in Zr-2.5Nb Pressure Tube (Zr-2.5Nb 압력관의 수화물에 의한 파괴인성 취화에 관한 연구)

  • Oh, Dong-Joan;Ahn, Sang-Bok;Park, Soon-Sam;An, Chang-Yun;Kim, Young-Suk
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.93-98
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    • 2000
  • Unpredictable failures can occur due to the DHC (delayed hydride cracking) or the degradation of fracture toughness by hydride embrittlement in CANDU pressure tube which can result from the absorption of hydrogen or deuterium in the high temperature coolant. To investigate the hydride embrittlement of CANDU Zr-2.5Nb pressure tube, the transverse tensile test and the fracture toughness test were performed from room temperature to $300^{\circ}C$ using three different specimens which have an AR (As Received), 100, and 200 ppm hydrogen. As the amount of absorbed hydrogen was increased, the transverse yield strength and the ultimate tensile strength were also increased. In addition, as the test temperature became higher they were decreased linearly. While, at room temperature, the hydrogenbsorbed specimens represented the embrittlement which resulted in sudden decreasing of fracture toughness, the fracture characteristics became ductile such as AR specimen at high temperatures. Through the observation of fracture surface using SEM, it was found that the stress state of mixed mode could be related to the fissure which was believed to decrease the global fracture toughness.

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Confinement Effects of High-Strength Reinforced Concrete Tied Columns

  • Han, Byum-Seok;Shin, Sung-Woo
    • International Journal of Concrete Structures and Materials
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    • v.18 no.2E
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    • pp.133-142
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    • 2006
  • An experimental study was conducted to investigate the effectiveness of transverse steel in reinforced concrete tied columns subjected to monotonically increasing axial compression. Eighteen large-scale columns($260{\times}260{\times}1,200mm$) were tested. Effects of such main variables as concrete compressive strength, configurations of transverse steel, transverse reinforcement ratio, spacing of transverse steel, and spalling of concrete cover were investigated. High-strength concrete columns under concentric axial loads show extremely brittle behavior unless the columns are confined with transverse steel that can provide sufficiently high lateral confinement pressure. A consistent decrease in the deformability of the column test specimens was observed with increasing concrete strength. Test results of this study were compared with existing confinement models of modified Kent-Park, Sheikh-Uzumeri, Mander, and Saatcioglu-Razvi. The comparison indicates many existing models to predict the behavior of confined concrete overestimate or underestimate the ductility of confined concrete.

Micro-EHL Analysis of a Ball Joint Contact with Surface Roughness (표면 거칠기를 고려한 볼 조인트 접촉의 미세 탄성유체윤활 해석)

  • 김태종
    • Tribology and Lubricants
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    • v.19 no.3
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    • pp.123-132
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    • 2003
  • The effect of surface texture on elastohydrodynamic lubrication (EHL) point contact of a ball Joint mechanism in small reciprocating compressors is studied numerically by using multigrid method. Pressure and film thickness profiles have been calculated for surface roughness with waviness of different orientations and transverse ridge and dent at minimum and maximum Hoes M parameter conditions. The influence of the amplitude and the wavelength of the surface roughness was also studied. Results show that the oblique waviness with orientation angle of 30$^{\circ}$generates the smallest minimum film thickness as compared with those of longitudinal, transverse, and other oblique roughness. The influence of transverse waviness on the minimum film thickness is smaller than for the longitudinal waviness case.

Hydrogen Embrittlement of Zr-2.5Nb PT with Temperature (Zr-2.5Nb 압력관의 온도변화에 따른 수소취화 파괴거동)

  • Oh, Dong-Joon;Ahn, Sang-Bok;Kim, Young-Suk
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.78-83
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    • 2003
  • The aim of this study is to investigate the effect of hydrogen embrittlement od Zr-2.5Nb CANDU pressure tube. The test were performed at three hydrogen contents for transverse tensile and CCT specimens while the test temperatures were changed (RT to 300$^{\circ}C$). The specimens were directly machined from the tube retaining original curvature using electric discharge machine. Both the transverse tensile and the fracture toughness tests showed the hydrogen embrittlement clearly at RT but this phenomenon was disappeared while the test temperature arrived over 250$^{\circ}C$. From the fracture toughness test, it was found that fracture toughness dJ/da was increased up to 200$^{\circ}C$ and then decreased.

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Unsteady Numerical Analysis of Transverse Injection Jet into Supersonic Mainstream (초음속 주유동에 수직 분사되는 제트의 비정상 수치해석)

  • Choi Jeong-Yeol;Yang Vigor
    • 한국전산유체공학회:학술대회논문집
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    • 2003.08a
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    • pp.126-131
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    • 2003
  • A series of computational simulations have been carried out for supersonic flows in a scram jet engine with and without a cavity. Transverse injection of hydrogen, a simplest form of fuel supply, is considered in the present study with the injection pressure varying from 0.5 to 1.5 MPa. The corresponding equivalence ratios are 0.167 - 0.50. The work features detailed resolution of the flow dynamics in the combustor, which was not typically available in most of the Previous studies. In particular, oscillatory flow characteristics are captured at a scale sufficient to identify the underlying physical mechanisms. Much of the flow unsteadiness is related not only to the cavity, but also to the intrinsic unsteadiness in the flowfield. The interactions between shock waves and shear layer may cause a large excursion of flow oscillation. The role of the cavity and injection pressure are examined systematically.

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Effect of Cobalt to Bronze Ratio on Transverse Rupture Strength of Diamond Segments

  • Unal, Rahmi
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1146-1147
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    • 2006
  • Diamond segments were fabricated by cold pressing and sintering under pressure at the temperature up to $750^{\circ}C$. Based on the results of this investigation, it can be concluded that the segments containing 39wt.% cobalt in the matrix material have the highest bending strength at a fracture probability of 50 % due to the weibull distribution method. According to the weibull statistics, it was also determined that the transverse rupture strength was the best for 39 wt.% cobalt ratio in the matrix material for the fracture probability when the other variables are the same.

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