교량-차량 동적상호작용을 고려한 시간가변적 시스템 특성 분석 = Identification of System Frequency Variations in Vehicle–Bridge Interaction Systems

다국어 초록 (Multilingual 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.

국문 초록 (Abstract)

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 보이는 것을 알 수 있다. 따라서 상호작용이 발생하는 시스템차수에 대한 이해가 필요함을 알 수 있다.

참고문헌 (Reference)

1 Farrar, C. R, "Variability of Modal Parameters Measured on the Alamosa Canyon Bridge" Los Alamos National Lab 1996

2 Zhang, Q. W, "Traffic‐Induced Variability in Dynamic Properties of Cable‐Stayed Bridge" 31 (31): 2015-2021, 2002

3 Li, J, "Natural Frequency of Railway Girder Bridges under Vehicle Loads" 8 (8): 199-203, 2003

4 Kim, R.E, "Hybrid Model for Railroad Bridge Dynamics" 142 (142): 04016066-, 2016

5 Yang, Y. B, "Frequency Variation in Vehicle–Bridge Interaction Systems" 13 (13): 1350019-, 2013

6 McGetrick, P.J, "Experimental Validation of a Drive-by Stiffness Identification Method for Bridge Monitoring" 14 (14): 317-331, 2015

7 Kim, C. Y, "Effect of Vehicle Weight on Natural Frequencies of Bridges Measured from Traffic-Induced Vibration" 2 (2): 109-115, 2003

8 OBrien, E. J, "Damage Detection using Curvatures Obtained from Vehicle Measurements" 7 (7): 333-341, 2017

9 Nagayama, T, "Bridge Natural Frequency Estimation by Extracting the Common Vibration Component from the Responses of Two Vehicles" 150 : 821-829, 2017

10 Farrar, C.R, "An Introduction to Structural Health Monitoring" 365 (365): 303-315, 2007

11 Sun, Z, "A Damage Detection Algorithm Utilizing Dynamic Displacement of Bridge under Moving Vehicle" 2016 : 8454567-, 2016