• Title/Summary/Keyword: 강성 개선

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현장 - "스티로폴 상자 종이스티커를 PS 재질로"

  • 한국발포스티렌재활용협회
    • 환경사랑
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    • s.63
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    • pp.10-11
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    • 2012
  • 국회 강성천 황영철 의원이 주최하고 자원순환연대가 주관하며 한국농어민신문과 당 협회가 후원한 '농수산물 스티로폴 상자 종이스티커 재질개선 간담회'가 지난 2월 29일 국회의원회관에서 열렸다. 이날 간담회에서 EPS 포장재의 재활용률을 높이고 상품의 이미지를 제고시키기 위해 종이 스티커 대신 PS(폴리스틸렌) 필름 스티커를 붙여야 한다는 데 의견이 모아졌다. 한국농어민신문이 정리한 이날 종합토론에서 개진 된 참석자들의 의견을 발췌했다.

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Evaluation of Gusset Plate Connection Stiffness in Braced Frames (가새 골조에서 거싯 플레이트 연결부의 강성 평가)

  • Yoo, Jung Han
    • Journal of Korean Society of Steel Construction
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    • v.21 no.2
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    • pp.105-113
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    • 2009
  • To improve braced frame performance, the connection strength, stiffness, and ductility must be directly considered in the frame design. The resistance of the connection must be designed to resist seismic loads and to help provide the required system ductility. In addition, the connection stiffness affects the dynamic response and the deformation demands on the structural members and connections. In this paper, current design models for gusset plate connections are reviewed and evaluated usingthe results of past experiments. Current models are still not sufficient to provide adequate connection design guidelines and the actual stress and strain states in the gusset plate are very nonlinear and highly complex. Design engineers want simple models with beam and column elements to make an approximate estimation of system and connection performance. The simplified design models are developed and evaluated to predict connection stiffness and system behavior. These models produce reasonably accurate and reliable estimation of connection stiffness.

Direct Inelastic Design of Reinforced Concrete Members Using Strut-and-Tie Model (스트럿-타이 모델을 이용한 철근콘크리트 부재의 직접 비탄성 설계)

  • Eom, Tae-Sung;Park, Hong-Gun
    • Journal of the Korea Concrete Institute
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    • v.20 no.3
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    • pp.345-356
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    • 2008
  • In the previous study, direct inelastic strut-and-tie model (DISTM) was developed to perform inelastic design of reinforced concrete members by using linear analysis for their secant stiffness. In the present study, for convenience in design practice, the DISTM was further simplified so that inelastic design of reinforced concrete members can be performed by a run of linear analysis, without using iterative calculations. In the simplified direct inelastic strut-and-tie model (S-DISTM), a reinforced concrete member is idealized with compression strut of concrete and tension tie of reinforcing bars. For the strut and tie elements, elastic stiffness or secant stiffness is used according to the design strategy intended by engineer. To define the failure criteria of the strut and tie elements, concrete crushing and reinforcing bar fracture were considered. The proposed method was applied to inelastic design of various reinforced concrete members including deep beam, coupling beam, and shear wall. The design results were compared with the properties and the deformation capacities of the test specimens.

Simplified 2D Analysis for Suspension Bridges Subject to Wind Excitation (현수교 풍진동에 관한 2D 간단해석 및 변수연구)

  • Kim, Woo Seok;Lee, Jaeha
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.6
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    • pp.463-470
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    • 2013
  • In this paper, 2D simple analyses were performed in order to predict the large torsional oscillations in a suspension bridge based on Makenna and Tuama model(2001). The existing model(Makenna and Tuama, 2001) has shown unrealistic results as the wind speed increases and frequency decreases. Furthermore, resonance could not be simulated by the existing model. Therefore, in this study, new model was proposed with a consideration of the torsional resistance. The vertical and rotational behaviors of the deck in the suspension bridge were analyzed. Analysis results showed that at first vertical oscillations were observed and it was gradually transformed to the rotation oscillations. With the consideration of the torsional resistance, it was shown that vertical behavior were stabilized as time passed. However, the rotational behavior was not stabilized and was kept until the end of analysis. Beat periods decreased while the wind speed increased. The resonance of the rotational mode was dependent to the rotational resistance. Obtained results could be applied for the design of the suspension bridge under the wind load.

Optimal Design for Torsional Stiffness of the Tubular Space Frame of a Low-Cost Single Seat Race Car (저가 입문용 1인승 레이스카 Tubular Space Frame의 비틀림 강성 최적설계)

  • Jang, Woongeun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.5955-5962
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    • 2014
  • Generally, the frame design of a vehicle is a critical technology that plays an important role in the racing and high performance sports car market. The high performance of race car frame means that it requires high torsional stiffness because it directly affects the cornering behavior of the race car. The optimal design for the frame of a low-cost single seat race car was carried out using the DOE (Design Of Experiments) with Taguchi's orthogonal array and FEM (Finite Element Method) analysis to secure sufficient torsional stiffness in this paper. According to the results by DOE and FEM analysis, the optimal design case produced improved 10.7% and 14.5% improvement in each stiffness-to-weight ratio and frame weight than in the early design step. Therefore, this paper shows that the optimal design with Taguchi's orthogonal array is very useful and effective for designing a tubular space frame of a low-cost single seat race car in the early design step.

A study on the Dynamic Behavior Enhancement of the Korean High-speed Train (고속열차의 주행동특성 개선에 관한 연구)

  • Jeon, Chang-Sung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.81-87
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    • 2017
  • This paper describes the dynamic behavior and enhancement of Korean high-speed trains. The tail vibration reduction method of the yaw damper installation method change, which was derived from previous research, was applied to the running test of high-speed train. In addition, the vibration reduction method for the entire vehicle was derived by a numerical method and its effect was confirmed by a running test. The improved design was applied to the double-deck high-speed train coaches and the commissioning proceeded without problems in dynamic behavior. Sensitivity analysis of the suspension parameters affecting the critical speed of Korean next-generation high-speed trains was performed and four design variables that greatly affected the critical speed were derived. These were in the order of the primary elastic joint x-directional stiffness, the secondary yaw damper series stiffness, the secondary lateral damper damping coefficient, and the carbody damper damping coefficient. By optimizing the design variables, the suspension parameter that improves the critical speed by 23.3% can be used in the commercial designs of Korean next-generation high-speed trains.