• 제목/요약/키워드: Deformations

검색결과 1,617건 처리시간 0.022초

Correction of a post-traumatic scar fold in the lateral canthus using modified Z-plasty

  • Kim, Byeong Jun;Lee, Seung Jun
    • 대한두개안면성형외과학회지
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    • 제19권1호
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    • pp.51-54
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    • 2018
  • Post-traumatic scar deformations are common in many skin injury cases. These are usually aesthetic problems, but if these deformations impair mobility and the patient feels uncomfortable, we must resolve them. In a patient with a lateral post-traumatic scar fold in the lateral canthus that shortened the horizontal orbital fissure and created traction on eye opening, we performed modified classic Z-plasty, resulting in aesthetic and functional improvements without recurrence.

FEM Analysis of Plasticity-induced Error on Measurement of Welding Residual Stress by the Contour Method

  • Shin, Shang-Hyon
    • Journal of Mechanical Science and Technology
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    • 제19권10호
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    • pp.1885-1890
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    • 2005
  • The contour method relies on deformations that occur when a residually stressed component is cut along a plane. The method is based on the elastic superposition principle. When plasticity is involved in the relaxation process, stress error in the resulting measurement of residual stress would be caused. During the cutting the specimen is constrained at a location along the cut so that deformations are restrained as much as possible during cutting. With proper selection of the constraining location the plasticity effect can also be minimized. Typical patterns of longitudinal welding residual stress state were taken to assess the plasticity effect along with constraining locations.

Contribution of modification of a pressuremeter for an effective prediction of soil deformability

  • Aissaoui, Soufyane;Zadjaoui, Abdeldjalil;Reiffsteck, Philippe
    • Geomechanics and Engineering
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    • 제23권4호
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    • pp.381-392
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    • 2020
  • The difficulties, challenges and limitations faced in standard pressuremeter testing in the measurement of low soil deformations led a number of researchers to think about the possible modification of the equipment, and especially the replacement of the volumeter by a Hall Effect sensor. This article is a major contribution in this direction. It makes an attempt to detail the design, manufacture and operation of the new equipment. The calibration of the various components was carried out according to the rules presently in force. This proposal was applied, on an exploratory basis, to the data of a real site located in France. The authors present the preliminary results of some cyclic pressuremeter tests, previously carried out in the laboratory, on a sandy material, and they then provide a basic interpretation of these results. The findings indicated that the proposed apparatus is capable of providing high-quality information about constraints and deformations. Although these tests were performed within the laboratory, it was possible to analyze the power, quality, performance and insufficiencies of the proposed equipment.

광학기구기법을 이용한 가속기 진공챔버의 변형관측 (Deformation Measurement of Accelerator Vacuum Chamber Using Optical Tooling Technique)

  • 김병국
    • 대한토목학회논문집
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    • 제12권3호
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    • pp.181-194
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    • 1992
  • 광학기구기법을 이용하여, 포항방사광가속기(浦項放射光加速器) 본체(本體)의 일부인 진공챔버의 시제품 상하판(上下板)의 용접에 의한 변형과 초고진공(超高眞空)을 위한 Baking에 의한 변형을 관측(觀測)하였다. 이 변형의 관측(觀測)은 진공챔버 본 제품의 설계와 주변 설치물과의 간섭상태 파악 및 상대적 위치 관계를 정립하는데 기본자료를 제공함을 그 목적으로 하였다. 챔버의 변형관측(觀測)을 성공적으로 수행함으로써, 광화기구기법은 기계적(機械的) 정밀관측(觀測)의 대체안(代替案)으로서 그 효용성이 입증되었다.

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초고층건물의 기둥축소량 예측, 계측 및 보정 (Prediction, Field Measurement and Compensation of Column Shortening in Tall Building)

  • 조석희;김한수;김도균
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2003년도 학술.기술논문발표회
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    • pp.143-146
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    • 2003
  • Tall Buildings have been popular in recent years. Tall buildings require special consideration to design and construction due to their structural features. Column shortening is one of the important technologies to be considered in. The long-term deformations of concrete cause vertical shortening on cores and columns, trigger deformations on cladding, partitions and finishes, and damage their serviceability. This also affects structural stability by inducing unexpected stress to the structural members such as outrigger. The main objective of this paper is to re-evaluate column shortening according to revised field information and to compare the analysis results with the actual field measurement. Mok-Dong Hyperion, a 69-story apartment building which is currently under construction, was chosen for the case study.

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Inelastic behavior of standard and retrofitted rectangular hollow sectioned struts -I: Analytical model

  • Boutros, Medhat K.
    • Structural Engineering and Mechanics
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    • 제10권5호
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    • pp.491-504
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    • 2000
  • This paper is a presentation of a physical model for the elastic-partly plastic behavior of rectangular hollow section pinned struts subjected to static cyclic axial loading and the evaluation of the compressive strength of retrofitted damaged struts. Retrofitting is achieved by welding stiffening plates along the webs of damaged struts. The shape of the elastic and permanent deformations of the strut axis satisfy the conditions at the ends and midspan. Continuous functions of the geometric variables of stress distributions in the yielded zone are evaluated by interpolation between three points along each partly plastic zone. Permanent deformations of the partly plastic region are computed and used to update the shape of the unloaded strut. The necessity of considering geometric nonlinearity is discussed. The sensitivity of the results to the location of interpolation points, the shape of the permanent deformation and material hysteretic properties is investigated.

Use of SMA bars to enhance the seismic performance of SMA braced RC frames

  • Meshaly, Mohamed E.;Youssef, Maged A.;Abou Elfath, Hamdy M.
    • Earthquakes and Structures
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    • 제6권3호
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    • pp.267-280
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    • 2014
  • Shape Memory Alloy (SMA) braces can be used to reduce seismic residual deformations observed in steel braced Reinforced Concrete (RC) frames. To further enhance the seismic performance of these frames, the use of SMA bars to reinforce their beams is investigated in this paper. Three-story and nine-story SMA-braced RC frames are designed utilizing regular steel reinforcing bars. Their seismic performance is examined using twenty seismic ground motions. The frames are then re-designed using SMA reinforcing bars. Different design alternatives representing different locations for the SMA reinforcing bars are considered. The optimum locations for the SMA bars are identified after analysing the design alternatives. The seismic performance of these frames has indicated better deformability when SMA bars are used in the beams.

Measuring hull girder deformations on a 9300 TEU containership

  • Koning, Jos;Schiere, Marcus
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제6권4호
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    • pp.1111-1129
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    • 2014
  • A 9300 TEU container carrier was equipped in 2006 with instrumentation aimed at wave induced accelerations, and motions. In 2010 the system was extended with strain sensors to include structural loads. Section loads for vertical bending could be readily obtained but the originally intended derivation of horizontal bending and torsion from the measured strains was found to be unreliable. This paper addresses an alternative approach that was adopted in the post processing of results. In particular the concept to use acceleration sensors to capture global hull deformations along the length of the hull, and the use of a data fusion procedure to obtain section loads from combined sensor data and finite element calculations. The approach is illustrated by comparison of actually measured accelerations and local strains with values obtained from the data fusion model. It is concluded that the approach is promising but in need of further validation and development. In particular the number and shapes of the modes used may not have been sufficient to represent the true deflection and thus strain distributions along the high loaded areas.

단면 수정계수를 이용한 이동 하중에 따른 트러스 연결부의 응력해석 (Stress Analysis of Truss Connection subjected to Moving Load Using Section Properties Factor)

  • 이상호;배기훈
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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    • pp.354-361
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    • 2002
  • This paper propose section properties factor to generate stress history for fatigue analysis and safety inspection of steel bridge. A methodology is described for the computation of numerical stress histories in the steel truss bridge, caused by the vehicles using section properties factor. The global 3-D beam model of bridge is combined with the local shell model of selected details. Joint geometry is introduced by the local shell model. The global beam model takes the effects of joint rigidity and interaction of structural elements into account. Connection nodes in the global beam model correspond to the end cross-section centroids of the local shell model. Their displacements are interpreted as imposed deformations on the local shell model. The load cases fur the global model simulate the vertical unit force along the stringers. The load cases fer the local model are imposed unit deformations. Combining these, and applying vehicle loads, numerical stress histories are obtained. The method is illustrated by test load results of an existing bridge.

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용접변형 예측 및 가시화 프로그램 개발 (Development of a Program for Prediction and Visualization of Welding Deformations)

  • 서승일;노재규;이정수
    • Journal of Welding and Joining
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    • 제20권5호
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    • pp.113-119
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    • 2002
  • To prevent problems caused by welding deformation, preparation in the design stage is necessary. Countermeasures in the design stage is also the most cost-effective method. In this study, to give designers information on the welding deformation, a system to visualize the welding deformation is developed. The model to visualize the deformation is the stiffened plate common in steel structures. To increase computational efficiency, theoretical solutions to calculate the deformation of plate and stiffener are used instead of numerical analysis. Also, to secure accuracy, experiments to estimate bending moment causing welding deformations are performed. A computer program written with Visual C++ is developed for interactive data input, calculation of welding deformation and display of deformed shape. Designers can change the design in the early stage after checking the deformed shape by this system.