• Title/Summary/Keyword: VEDS

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An integrated optimal design of energy dissipation structures under wind loads considering SSI effect

  • Zhao, Xuefei;Jiang, Han;Wang, Shuguang
    • Wind and Structures
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    • v.29 no.2
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    • pp.99-110
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    • 2019
  • This paper provides a simple numerical method to determine the optimal parameters of tuned mass damper (TMD) and viscoelastic dampers (VEDs) in frame structure for wind vibration control considering the soil-structure interation (SSI) effect in frequency domain. Firstly, the numerical model of frame structure equipped with TMD and VEDs considering SSI effect is established in frequency domain. Then, the genetic algorithm (GA) is applied to obtain the optimal parameters of VEDs and TMD. The optimization process is demonstrated by a 20-storey frame structure supported by pile group for different soil conditions. Two wind resistant systems are considered in the analysis, the Structure-TMD system and the Structure-TMD-VEDs system. The example proves that this method can quickly determine the optimal parameters of energy dissipation devices compared with the traditional finite element method, thus is practically valuable.

자율운항선박 통신기술 및 사이버보안 기술에 관한 연구

  • 박개명;안종우;유진호;손금준
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2022.11a
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    • pp.271-273
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    • 2022
  • 자율운항선박의 안전한 운항을 위해서는 선박과 선박, 육상과 선박 간의 통신이 무척 중요하다. 또한 자율운항을 위하여 육상과 선박 간, 선박 내 시스템 간의 빈번한 통신 및 데이터 교환으로 인하여 사이버 공격에 취약해지기 때문에 이를 방어하기 위한 사이버보안 기술의 개발 역시 필요하였다. 이에 자율운항선박 기술 개발 사업 중 통신 기술 및 사이버보안 기술 개발 현황에 소개하고자 한다.

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Control of the along-wind response of steel framed buildings by using viscoelastic or friction dampers

  • Mazza, Fabio;Vulcano, Alfonso
    • Wind and Structures
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    • v.10 no.3
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    • pp.233-247
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    • 2007
  • The insertion of steel braces has become a common technique to limit the deformability of steel framed buildings subjected to wind loads. However, when this technique is inadequate to keep floor accelerations within acceptable levels of human comfort, dampers placed in series with the steel braces can be adopted. To check the effectiveness of braces equipped with viscoelastic (VEDs) or friction dampers (FRDs), a numerical investigation is carried out focusing attention on a three-bay fifteen-storey steel framed building with K-braces. More precisely, three alternative structural solutions are examined for the purpose of controlling wind-induced vibrations: the insertion of additional diagonal braces; the insertion of additional diagonal braces equipped with dampers; the insertion of both additional diagonal braces and dampers supported by the existing K-braces. Additional braces and dampers are designed according to a simplified procedure based on a proportional stiffness criterion. A dynamic analysis is carried out in the time domain using a step-by-step initial-stress-like iterative procedure. Along-wind loads are considered at each storey assuming the time histories of the wind velocity, for a return period $T_r=5$ years, according to an equivalent wind spectrum technique. The behaviour of the structural members, except dampers, is assumed linear elastic. A VED and an FRD are idealized by a six-element generalized model and a bilinear (rigid-plastic) model, respectively. The results show that the structure with damped additional braces can be considered, among those examined, the most effective to control vibrations due to wind, particularly the floor accelerations. Moreover, once the stiffness of the additional braces is selected, the VEDs are slightly more efficient than the FRDs, because they, unlike the FRDs, dissipate energy also for small amplitude vibrations.