• Title/Summary/Keyword: Relative Deformation

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Arbitrary Lagrangian Eulerian (ALE) Formulations of Saturated Porous Media (포화 다공질 매체의 Arbitrary Lagrangian Eulerian (ALE) 정식화)

  • 박대효;정소찬
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.04a
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    • pp.235-242
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    • 2003
  • The solids and the fluids in porous media have a relative velocity to each other. Due to physically and chemically different material properties and their relative velocity, the behavior of saturated porous media is extremely complicated. Thus, in order to describe and clarify the deformation behavior of saturated porous media, constitutive models for deformation of porous media coupling several effects such as flow of the fluids or thermodynanical change need to be developed in frame of Arbitrary Lagrangian Eulerian (ALE) description. The aim of ALE formulations is to maximize the advantages of Lagrangian and Eulerian elements, and to minimize the disadvantages. Therefore, this method is appropriate for the analysis of porous media that are considered for the behavior of the solids and the fluids. In this work, governing equations of porous media based on ALE description are obtained from governing equations in frame of updated Lagrangian description. Then, weak forms of these equations are derived using arbitrary weighting functions.

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Study on the Long-term Behavior of SRC Columns Considering the Differential Moisture Distribution in a Section (단면 내의 부등수분분포를 고려한 SRC 기둥의 장기거동에 관한 연구)

  • Seol Hyun-Cheol;Kim Jin-Keun;Kim Yun-Yong;Kwon Seung-Hee;Kim Han-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.109-112
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    • 2004
  • It was found from the previous experimental studies that the long-term deformation of SRC columns was quite different from that of RC columns. A new approach method is needed to quantitatively predict the long-term deformation of SRC columns. In this study, the causes of the difference between the behaviors of RC and SRC columns are investigated and discussed. SRC columns exhibit a time-dependent relative humidity distribution in a cross section differently from that of RC columns due to the presence of a flange, which interferes with the moisture diffusion of concrete. This different relative humidity distribution may reduce the drying shrinkage and the drying creep in comparison with RC columns.

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Adhesive, Friction, and Deformation Behaviors of Pig Skin under Various Exposure Times to Air (돼지피부의 공기노출 시간에 따른 응착, 마찰 및 변형거동)

  • Shin, Hyunduk;Ahn, Hyo-Sok
    • Tribology and Lubricants
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    • v.30 no.1
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    • pp.36-45
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    • 2014
  • Understanding steel/skin contact phenomena is important for the study of object manipulation in robotics and has been a topic of great interest. In this study, pig skin was taken as a surrogate model for human skin, and its adhesive, friction, and deformation behaviors were measured under various exposure times to air. Indentation, friction, and scratch tests were performed at $25^{\circ}C$ and 45% relative humidity. The influences of adhesion and deformation on the coefficient of friction were characterized; the pig skin was found to be sensitive to the sliding velocity and normal load under the controlled experimental conditions.

Study on The Estimation of Pipeline.Soil Interaction Force during Longitudinal Permanent Ground Deformation (종방향 영구지반변형 발생시 관.지반 상호작용력의 산정에 관한 연구)

  • 김태욱;임윤묵;김문겸
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.09a
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    • pp.114-122
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    • 2002
  • The ASCE formula of lifeline.soil interaction force is the basis of semi-analytical relationship for buried pipelines subjected to longitudinal permanent ground deformation due to seismic induced liquefaction. However, since the ASCE formula has been developed based on the stiffness of non-liquefied region, it is needed to modify for the varied stiffness of liquefied region. With this object, the consideration of decreasing effect of soil stiffness in liquefied region is made: i.e. the spatial distributions of pipeline-soil interaction force in liquefied region. It means that the improved formula can reflect various patterns of permanent ground deformation more realistically. Through the comparative analyses using both the improved and ASCE formula, the applicability of the improved and the limitation of the ASCE formula and semi-analytical relationship are discussed. Also, relative influences of various parameters are evaluated for the clarification of behavior of pipeline subjected to longitudinal permanent ground deformation due to liquefaction.

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Effect of {10ī2} Twinning Characteristics on the Deformation Behavior of Rolled AZ31 Mg Alloy ({10ī2} 쌍정 특성이 AZ31 마그네슘 합금 압연재의 변형거동에 미치는 영향)

  • Park, S.H.;Hong, S.G.;Lee, J.H.;Lee, C.S.
    • Transactions of Materials Processing
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    • v.19 no.7
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    • pp.416-422
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    • 2010
  • The $\{10\bar{1}2\}$ twinning characteristics, such as active twin variants, volume fraction of twins with strain, twin morphology, twin texture and angle relationship between twins, were dependent on the activation mode (i.e., tension parallel to the caxis or compression perpendicular to the c-axis). The selection criterion of active twin variants was governed by the Schmid law. This activation of selected twin variants depending on the activation mode consequently caused a totally different plastic deformation behavior in two activation modes. The differences in the deformation characteristics, such as flow stress and work hardening rate, between both activation modes were explained in relation with activation stresses for slips and twinning, relative activities of twinning and slips during plastic deformation, grain refining effect by twin boundaries (Hall-Petch effect), and twinning-induced change in activities of slips.

Study on Earthquake Response characteristics of Building frames with energy absobers installed in Beams (보 제진 라멘의 변형특성에 관한 연구)

  • Lee, Ho
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1997.04a
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    • pp.191-198
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    • 1997
  • The subject of this thesis is the vibration response of framed structure for buildings of "damed beam" type. In steel rigid frame with damped beams, web plate in mid span of beams is perforated to form a rectangular opening, only upper and lower flanges being remained. When the frame is subjected to horizontal seismic forces, dominant shearing deformation takes place in the opening part of the beams. Energy absorber in stalled in the opening is driven by relative displacement caused by the shearing deformation and provide the frame with damping force. First, static deformation of portal frames having a beam with the web opening is discussed and formulas of elastic deformation is derived.s derived.

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Estimation of Surface Forces in Micro Rough Surface Contacts

  • Kim, Doo-In;Ahn, Hyo-Sok;Choi, Dong-Hoon
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.63-64
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    • 2002
  • In a micro-scale contact, surface forces such as capillary force and van der Waals Interaction significantly Influence the contact between asperities of rough surfaces. Little is, however, known about the variation of these surface forces as a function of chemical property of the surface (hydrophilicity), relative humidity and deformation of asperities In the real area of contact. A better understanding of these surface forces is of great necessity in order to find an optimal solution for reducing friction and adhesion of micro surfaces. We proposed an effective method to analyze capillary and van der Waals forces In nano-scale contact. In this method, Winklerian foundation model was employed to analyze the contact of rough surfaces that were obtained from atomic force microscopy (AFM) height Images. Self-mated contact of diamond-like-carbon (DLC) coatings was analyzed, as an example, by the proposed model. It was shown that the capillary force was significantly influenced by relative humidify and wet angle of the DLC surface. The deformation of asperities to a critical magnitude by external loading led to a considerable increase of both capillary and van der Waals forces.

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Cellular-level Biomechanics of Ultrasound (초음파의 세포 단위 생체역학)

  • Ohm, Won-Suk
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.1E
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    • pp.28-37
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    • 2010
  • This article reviews recent developments in the emerging field of cellular-level biomedical ultrasonics with the specific focus on the mechanics of ultrasound-cell interaction. Due to the nature of the field at its relative infancy, the review poses more questions than it provides answers. Discussed are topics such as the basic structure of a biological cell, the origin of cell's elasticity, a theoretical framework for ultrasound-cell interaction, and shape deformation of cells and its measurement, Some interesting problems for future study are proposed.

압축응력인가에 따른 적층 액츄에이터의 특성

  • 고중혁;송재성;홍원표;최헌종;정순종
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • 2004.05a
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    • pp.263-267
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    • 2004
  • This study presents the combined effect of electric field application and mechanical compressive stress loading on deformation in a multilayer ceramic actuator, designed with stacking 0.2($PbMn_{1/3}Nb_{2/3}O_{3}$)-0.8($PbZr_{0.475}Ti_{0.525}O_{3}$) ceramics and Ag-Pd electrode, alternately. The deformation behaviors were attributed to relative $180^{\circ}$domain, determined by pre-loaded compressive stress and electric field. The non-linearity of piezoelectricity and strain are dependent upon the young's modulus resulting from the domain reorientation.

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A Study on the Ground Deformation by lowering of Slurry level after Trench Excavation (트렌치굴착 후 안정액 수위 저하에 의한 지반변형에 관한 연구)

  • Hong, Won-Pyo;Han, Jung-Geun;Shin, Kwan-Young;Lee, Mun-Ku
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.1455-1460
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    • 2005
  • This paper presents the results of an experimental study on the ground deformation by trench excavation for Diaphragm Wall construction. The model tests are performed to investigate the back ground deformation by lowering of slurry level in trench after excavating. Through these, the deformation characteristic of the back ground due to stress release of excavated space was investigated. This study considered relative density of soil mass and the distance between trench and surcharge. An experiment was performed in order to observe the failure pattern of a slurry-supported trench excavated in sandy ground. From model tests, in order to predict reasonably the deformation behavior of the adjacent ground due to the underground excavation, it is significantly recommended that the ground settlement by trench excavation should be considered.

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