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Identification of System Frequency Variations in Vehicle-Bridge Interaction Systems

교량-차량 동적상호작용을 고려한 시간가변적 시스템 특성 분석

  • Lee, Jaehun (Deprartment of Civil & Environmental Engineering, Hanynag University) ;
  • Lee, Young Jae (Deprartment of Civil & Environmental Engineering, Hanynag University) ;
  • Kim, Robin Eunju (Deprartment of Civil & Environmental Engineering, Hanynag University)
  • 이재훈 (한양대학교 건설환경공학부) ;
  • 이영재 (한양대학교 건설환경공학부) ;
  • 김은주 (한양대학교 건설환경공학부)
  • Received : 2021.11.04
  • Accepted : 2021.11.17
  • Published : 2022.02.28

Abstract

Natural frequency variations in a vehicle-bridge interaction system is examined. The interaction system is designed for a simple beam subject to a moving vehicle. The equation of motion for the system is derived under the quarter-car condition, and numerical simulation is performed. Frequency amplification ratio (FAR) is defined as a ratio between the initial and the varying natural frequency of the system; a discontinuity in the FAR implies a resonance condition. Analysis is mainly focused on patterns, frequency variation characteristics, and discontinuity points of the FAR under the vehicle mass and tire stiffness variations. The result reveals that the interactions between the system affects the natural frequency of both the vehicle and the bridge in similar frequency regions that can be visually identified at the middle of the span using the FAR.

본 연구에서는 차량-교량 상호작용 시스템의 고유진동수 변화를 분석하였다. 차량이 주행하는 교량의 동특성은 차량의 질량 및 진동을 무시하지 않는 경우 상호작용을 반영해야 하는데, 이때 시스템은 시간가변적이므로 고유진동수 또한 시간가변적인 특성을 보인다. 따라서 본 연구에서는 차량과 교량을 각각 2자유도를 갖는 시스템으로 모델링하여 차량의 위치와 질량비 그리고 시스템 강성비에 따른 시간가변적 고유진동수를 산출하였다. 분석 결과 일반적으로 초기 고유진동수가 작은 시스템은 상호작용으로 인하여 증폭비가 낮아지는 추세를 보이나 상호작용이 발생할 경우 증폭비는 분기점을 보이며 비선형적 추세를 보이는것을 알 수 있다. 따라서 상호작용이 발생하는 시스템차수에 대한 이해가 필요함을 알 수 있다.

Keywords

Acknowledgement

본 연구는 국토교통부/국토교통과학기술진흥원 국토교통촉진연구사업(No. 21CTAP-C164093-01)의 지원을 받아 수행되었습니다.

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