• Title/Summary/Keyword: pratt

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An Analysis of Mechanical Features and Variations of Design Composition Elements for Pratt Trusses (프랫트러스의 디자인 구성요소 변화와 역학적 특성분석)

  • Park, Chan-Soo;Lee, Ju-Na
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.2
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    • pp.47-55
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    • 2013
  • The design composition elements and the mechanical behavior of trusses have been investigated for Pratt trusses. As a result, it was determined that the design composition elements of the trusses consist of the composition of webs, the distance between joints, the chords profile, the depth of the truss, and the double chord composition. In addition, by analyzing models with a variation of elements, comprehensive features of structural behavior have been presented for variations of design of Pratt trusses. This is to provide more effective and useful design information on truss structure in the architectural and structural planning stage.

Xen Virtualization

  • Pratt, Ian;Spector, Stephen
    • Communications of the Korean Institute of Information Scientists and Engineers
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    • v.26 no.10
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    • pp.14-18
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    • 2008

A Study on the Structural Behaviour of Staggered Truss System by the Shape of Truss (트러스 형태에 따른 스태거드트러스 골조시스템의 구조특성에 관한 연구)

  • Rha, Chang-Soon;Hong, Yoon-Soo;Yu, Eun-Jong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.3
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    • pp.199-206
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    • 2017
  • This paper analyzed structural behaviors of the staggered truss system, typically used in low seismicity regions, resisting the lateral loads such as wind and seismic load. A comparative study of cost and efficiency was carried out by analysing and designing the 10- and 20-story buildings with various types of truss, including pratt, howe, warren, K-, and vierendeel, which may typically be used in staggered truss system. In design, column and truss members are selected in group, and the efficiency of the member design was judged by average demand capacity ratio of the all members in same group. And economic analysis of the system was investigated by the quantity of the structural members. As a result, staggered truss system with the pratt truss and warren truss showed the most economical and efficient performance for 10-story building, and 20-story building, respectively.

The Comparison of Sphere Fitting Methods for Estimating the Center of Rotation on a Human Joint (인체관절의 회전중심 추정을 위한 구적합법의 비교)

  • Kim, Jin-Uk
    • Korean Journal of Applied Biomechanics
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    • v.23 no.1
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    • pp.53-62
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    • 2013
  • The methods of fitting a circle to measured data, geometric fit and algebraic fit, have been studied profoundly in various areas of science. However, they have not been applied exactly to a biomechanics discipline for locating the center of rotation of a human joint. The purpose of this study was to generalize the methods to fitting spheres to the points in 3-dimension, and to estimate the center of rotation of a hip joint by three of geometric fit methods(Levenberg-Marquardt, Landau, and Sp$\ddot{a}$th) and four of algebraic fit methods(Delogne-K${\aa}$sa, Pratt, Taubin, and Hyper). 1000 times of simulation experiments for flexion/extension and ad/abduction at an artificial hip joint with four levels of range of motion(10, 15, 30, and $60^{\circ}$) and three levels of angular velocity(30, 60, and $90^{\circ}$/s) were executed to analyze the responses of the estimated center of rotation. The results showed that the Sp$\ddot{a}$th estimate was very sensitive to the marker near the center of rotation. The bias of Delogne-K${\aa}$sa estimate existed in an even larger range of motion. The Levenberg-Marquardt algorithm of geometric fit and the Pratt of algebraic fit showed the best results. The combination of two methods, using the Pratt's estimate as initial values of the Levenberg-Marquardt algorithm, could be a candidate of more valid estimator.