• Title/Summary/Keyword: Built-up Structure

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A Study on the Sructural Behavior of Welded Built-up H-Beams for On-line Monitoring System (온-라인 구조물 계측 시스템을 위한 용접조립 H형강보의 구조적 거동에 관한 연구)

  • Ahn, Hyung-Joon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.2
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    • pp.127-133
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    • 2002
  • Most structures are constantly influenced by repeated weathering phenomena and load action during a period of its utilization, and their component materials become superannuated and their design performance becomes slowly lost. Therefore, it is thought that it is necessary to develop the online monitoring system that can make a great contribution to the maintenance management and disaster prevention of the building structure by sensing any slight change of the entire structure regardless of its inside and outside. Especially, this study was intended to explain the entire system of the online structure by interpreting welded built-up H-beams, of structural steel members having many advantages in terms of the qualities of structural materials, through limit state design, and presenting the basic plan to apply it to the structure.

The Prevention of the Longitudinal Deformation on the Built­Up Beam by using Induction Heating

  • Park, J.U.;Lee, C.H.;Chang, K.H.
    • International Journal of Korean Welding Society
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    • v.3 no.2
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    • pp.7-14
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    • 2003
  • During the manufacture of a ship, longitudinal deformation is produced by fillet welding on the Built­Up beam used to improve the longitudinal strength of a ship. This deformation needs a correcting process separate from a manufacture process and decreases productivity and quality. This deformation is caused by welding moment, which is the value multiplied the shrinking force due to welding by the distance from the neutral axis on a cross section of Built­Up beam. This deformation can be offset by generating a moment which is the same magnitude with and is located in an opposite direction to the welding moment on web plate by induction heating. Accordingly, this study clarifies the creation mechanism of the longitudinal deformation on Built­Up beam with FEM analysis and presents the preventative method of this deformation by induction heating basing the mechanism and verifies its validity through analysis and experiments. The induction heating used here is performed by deciding its location and quantity with experiments and simple equations and by applying them to a real structure.

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Study on Change in Landscape Structure over Time in Suburban Area by Using GIS -Case Study of Kawachinagano City, Osaka-

  • Kaga, Horoyuki;Izaki, Noriaki;Shimomura, Yasuhiko;Masuda, Noboru
    • Journal of the Korean Institute of Landscape Architecture International Edition
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    • no.1
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    • pp.67-74
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    • 2001
  • Now that importance of landscape planning unique to each area is emphasized, it is necessary to conduct landscape planning by taking advantage of natural environments unique to each ares, because its natural environments are regarded as one of the assets the area possesses. This study targets at Kawachinagano City, Osaka, one of the residential areas that I not only rich in natural and historical elements, but also has been rapidly growing. The purposes of this study are to evaluate change in landscape structure over time by analyzing relation between landform and pattern of expanding the built-up area at three time points of 1932, 1967, and 1994 with GIS (ARC/INFO 7.0.3, ARC/View 3.0 (ESRI)), as well as to make some suggestions for planning landscape unique to the area. Data on main ridges, sub ridges, main rivers, and other landform were read from the elevation map, and data on woodland, and parks and open spaces (having more than 3 ha area) were read from the existing land use map. The data were used to understand the natural structure of the city from topographic viewpoint. Next, the existing land use map prepared with data on the built-up area and urban axes consisting of roads and streets were overlaid on the elevation map in order to understand relation between pattern of expanding the built-up area and the natural structure.

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Wave Transmission Analysis of Semi-infinite Mindlin Plates Coupled at an Arbitrary Angle (임의의 각으로 연성된 반무한 Mindlin 판의 파동전달해석)

  • Park, Young-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.12
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    • pp.999-1006
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    • 2014
  • Mindlin plate theory includes the shear deformation and rotatory inertia effects which cannot be negligible as exciting frequency increases. The statistical methods such as energy flow analysis(EFA) and statistical energy analysis(SEA) are very useful for estimation of structure-borne sound of various built-up structures. For the reliable vibrational analysis of built-up structures at high frequencies, the energy transfer relationship between out-of-plane waves and in-plane waves exist in Mindlin plates coupled at arbitrary angles must be derived. In this paper, the new wave transmission analysis is successfully performed for various energy analyses of Mindlin plates coupled at arbitrary angles.

A study of Heat Analysis on Track Rubber Parts (궤도고무부품의 열해석에 관한 연구)

  • Kim, Young-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.9
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    • pp.117-122
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    • 1999
  • Track rubber parts has heat built-up as long as dynamic loading is applied from running tracked vehicles. Durability is required for rubber part to sustain the heat accumulation and heat exchange between rubber-metal assembly and environmental air and ground. For this research, the track assembly was divided into four parts i.e., bottom track shoe, upper track pad, pin busing and metal structure. Three rubber parts and metal structure were modelled and analyzed with MARC package program to obtain time-temperature data which was induced form mechanical work of tracked vehicles. heat accumulation data was obtained from special experiments under the room temperature of 25$^{\circ}C\;and\;35^{\circ}C$ to simulate the actual environmental conditions. From this research, it is cleared that the environmental temperature does not affect to the heat accumulation speed in rubber parts. Also, the heat built-up mechanism was clarified from the thermo-mechanical work based on numerical analysis and experiments.

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Minimum Weight Design of Built-up T Based on HCSR (HCSR 기반 T형 조립부재의 최소중량설계)

  • Shin, Sang-Hoon;Ko, Dae-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.6
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    • pp.389-394
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    • 2017
  • In a conventional ship structure, stiffeners with an asymmetric section, such as inverted angles, are used widely despite the disadvantage of strength compared to the stiffeners with a symmetric section, such as a built-up T. On the other hand, T-type built-up members are attracting more attention than L-type inverted angles due to the increased size of ships. The purpose of this study was to develop an optimal design program for a built-up T, and apply an evolution strategy as an optimization technique. In the optimization process, the gross thickness concept was adopted for the design variables and objective function, and the constraints are set up based on HCSR (Harmonized Common Structural Rules). Using the developed program in this study, the optimal stiffener design was carried out for 300K VLCC and 158K COT of which the orders were obtained lately. The optimal results revealed the weight reduction effect of 144 tons and 60 tons, respectively.

THE PREVENTION OF THE LONGITUDINAL DEFORMATION DUE TO FILLET WELDING BY USING INDUCTION HEATING

  • Park, Jeong-Ung;Lee, Chin-Hyung;Chang, Kyong-Ho
    • Proceedings of the KWS Conference
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    • 2002.10a
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    • pp.816-825
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    • 2002
  • During the manufacture of a ship, longitudinal deformation is produced by fillet welding on the BuiltUp beam used to improve the longitudinal strength of a ship. This deformation needs a correcting process separate from a manufacture process and decreases productivity and quality. This deformation is caused by welding moment, which is the value multiplied the shrinking force due to welding by the distance from the neutral axis on a cross section of Built-Up beam. This deformation can be offset by generating a moment which is the same magnitude with and is located in an opposite direction to the welding moment on web plate by induction heating. Accordingly, this study clarifies the creation mechanism of the longitudinal deformation on Built-Up beam with FEM analysis and presents the preventative method of this deformation by induction heating basing the mechanism and verifies its validity through analysis and experiments. The induction heating used here is performed by deciding its location and quantity with experiments and simple equations and by applying them to areal structure.

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Structural Behavior of Welded Built-up Square CFT Column to Beam Connections with External Diaphragm (용접조립 각형 CFT 기둥-보 외다이아프램 접합부의 구조 거동)

  • Lee, Seong Hui;Kim, Young Ho;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.28 no.2
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    • pp.75-83
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    • 2016
  • Existing tubes for concrete filled tubular structure are made through welding of four plates irrespective, but the production performance is poor and special welding technique is needed to weld the internal or through diaphragm. Accordingly, We developed a welded built-up square steel tube having a welding lines and a stiffeners at location out of stress concentration. The welded built-up square steel tube occurred a interference with stiffeners at the internal or through diaphragm, therefore researches of a external diaphragm for welded built-up square CFT column connections are needed for the purpose of avoidance of a interfere with stiffeners. In this study we suggest a design formulation for external diaphragm of the welded built-up square CFT external diaphragm connections. Four specimens were manufactured for a experimental test, then we analyzed the behaviors of the specimens.

Strength Evaluation for Adhesive Bonds of Adhesive with FRP Ship Body Structure (FRP 선체구조용 접착제의 접착강도 평가)

  • Ahn, Seok-Hwan;Choi, Han-Kyu;Nam, Ki-Woo
    • Journal of Ocean Engineering and Technology
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    • v.24 no.1
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    • pp.146-152
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    • 2010
  • Recently, the applied frequency of composite materials was increased from the viewpoint of lightweight, high strength and low cost when a leisure boat and a fishing boatwere built. However, studies on the mechanical properties of composite material with ship are rare. Specially, a leisure boat and fishing boat with FRP had been built by hand lay-up method. However, the vacuum infusion method is rising recently for ship building. The manufactured these FRP plates were combined by using the adhesive. Therefore, in this study Cleavage peel strength, Shear strength and fatigue limit of adhesive bonds by tensileloading were estimated. From test results, the strengths of FRP specimens made by the vacuum infusion method are higher than that of the hand lay-up method.