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와류하중모델을 고려한 공력감쇠비 추정법

Estimation of Aerodynamic Damping Considering Vortex Wind Load Model

황재승|김태민
한국풍공학회|2024.09|한국풍공학회지 (Journal of the Wind Engineering Institute of Korea)|제28권 제3호|pp. 43-49|DOI 10.37109/weik.2024.28.3.43

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키워드

White noise백색잡음와류하중하중모델가상 동적 가진기공력감쇠Vortex induced loadLoad modelVirtual dynamic shakerAerodynamic damping

초록

건축 토목 구조물에 작용하는 하중은 알 수 없는 경우가 대부분이므로 구조물에 대한 시스템 식별 알고리듬은 외부하중을 백 색잡음으로 가정한다. 이러한 가정은 일면 타당성이 있으나 와류하중과 같이 스펙트럼이 특정한 형태를 가지고 있는 경우 모달 파라 미터 특히 감쇠비 추정의 불확실성의 원인이 되고 있다. 본 연구에서는 구조물의 응답으로부터 역 계산된 하중을 이용하여 하중모델 을 구축하고 이를 이용하여 감쇠비를 추정하는 새로운 기법을 제안한다. 본 제안 기법은 외부하중을 백색잡음으로 가정하는 기존 VDS 기법을 기반으로 외부하중 스펙트럼 모델을 고려할 수 있는 보다 일반화된 기법이다. 제안된 추정기법을 직사각형단면 공탄성모델에 대한 공기력진동실험으로 수행하여 구한 가속도 응답에 적용하여 감쇠비추정의 신뢰성을 검증하였다. 풍속에 따라 풍하중 모델을 구 축하고 와류공진, 와류공진 전 후의 공력감쇠비를 평가한 결과 안정적이며, 신뢰도가 높은 감쇠비 추정이 가능함을 알 수 있었다.

Abstract

Since the dynamic wind loads on slender structures like tall buildings are mostly unknown, a white noise assumption of the external loads is applied to the most system identification algorithms for the structures. This assumption is justified very well most cases, however, it would be an uncertainty in the estimation of modal parameters, especially damping ratios, when a load spectrum has a specific shape, such as vortex shedding. In this study, a novel technique is proposed for estimating damping ratios by including load model which is back-calculated from the structure's responses. Based on the existing VDS technique, which assumes the external loads as a white noise, the proposed technique is more generalized so that the external load spectrum model could be considered. In order to verify the applicability of the damping ratio estimation, the proposed technique is applied to the acceleration response obtained from an aeroelastic model test for a rectangular cross-section model. Vortex induced load model parameters are identified and then the load model is used to evaluate the damping ratio according to the wind speed(before and after vortex resonance and vortex resonance). it is shown from the results that a stable and reliable damping ratio estimation can be obtained.

참고문헌 (18)

  1. Chauhan, S., "Using the Unified Matrix Polynomial Approach (UMPA) for the development of the Stochastic Subspace Identification (SSI) algorithm", Journal of Vibration and Control, 19(13), pp.1950~1961 (2013)
  2. Peeters, B., "Stochastic system identification for operational modal analysis: A Review", ASME Journal of Dynamic Systems, Measurement, and Control, 123, pp.659~667 (2001)
  3. Van Overschee, P., "Subspace Identification for Linear Systems: Theory-Implementations- Applications" (1996), Kluwer Academic Publishers
  4. Caicedo, J., "Natural excitation technique and eigensystem realization algorithm for phase I of the IASC-ASCE benchmark problem: simulated data", Journal of Engineering Mechanics, 130(1), pp.49~60 (2004), ASCE
  5. Chang, M., "Modified natural excitation technique for stochastic modal identification", Journal of Structural Engineering, 139(10), pp.1753~1762 (2013), ASCE
  6. James, G. H., "The natural excitation technique (NExT) for modal parameter extraction from operating structures", Modal Analysis, 10, pp.260~277 (1995)
  7. Brincker, R., "Modal Identification of Output-Only Systems using Frequency Domain Decomposition", Proceedings of the European COST F3Conference on System Identification & Structural Health Monitoring, pp.273~282 (2000)
  8. Antoni, J., "A study and extension of secondorder blind source separation to operational modal analysis", Journal of Sound and Vibration, 332, pp.1079~1106 (2013)
  9. Belouchrani, A., "A Blind Source Separation Technique Using Second-Order Statistics", Transaction on Signal Processing, 45(2), pp.434~444 (1997), IEEE
  10. Ghahari, S. F., "Blind modal identification of non-classically damped structures under nonstationary excitations", Structural Control and Health Monitoring, 24, pp.e1925~ (2017)
  11. Kerschen, G., "Physical interpretation of independent component analysis in structural dynamics", Mechanical Systems and Signal Processing, 21, pp.1561~1575 (2007)
  12. Sadhu, A., "A review of outputonly structural mode identification literature employing blind source separation methods", Mechanical Systems and Signal Processing, 94, pp.415~431 (2017)
  13. Kareem, A., "Acrosswind response of buildings", Journal of the Structural Division, 108(4), pp.869~887 (1982), ASCE
  14. Kareem, A., "Model for prediction of the acrosswind response of buildings", Engineering Structures, 6(2), pp.136~141 (1984)
  15. Vickery, B. J., "Across-wind vibrations of structures with circular cross-section, Part I : Development of a mathematical model for full-scale application", Journal of Wind Engineering and Industrial Aerodynamics, 12, pp.75~97 (1983)
  16. Hansen, S. O., "Vortex-induced vibrations of structures", Structural Engineers World Congress (2007)
  17. Hwang, J. S., "A Estimation Method of Wind Load using the Acceleration of Building", Journal of Wind Engineering Institute of Korea, 9(2), pp.197~207 (2005)
  18. Hwang, J. S., "Estimation of Damping Ratio of a Structure by a Virtual Mass Tuner", Journal of the Wind Engineering Institute of Korea, 20(1), pp.65~70 (2016)

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