Wind and Structures

  • 제24권4호
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  • Pages.351-365
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  • 2017
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  • 1226-6116(pISSN)
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  • 1598-6225(eISSN)
테크노프레스 (Techno-Press)
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DOI QR코드

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Alternative numerical method for identification of flutter on free vibration

  • Chun, Nakhyun (School of Civil, Environmental and Architectural Engineering, Korea University) ;
  • Moon, Jiho (Department of Civil Engineering, Kangwon National University) ;
  • Lee, Hak-Eun (School of Civil, Environmental and Architectural Engineering, Korea University)
  • 투고 : 2016.10.12
  • 심사 : 2017.02.22
  • 발행 : 2017.04.25
⟨ 이전 논문 다음 논문 ⟩

초록

The minimization method is widely used to predict the dynamic characteristics of a system. Generally, data recorded by experiment (for example displacement) tends to contain noise, and the error in the properties of the system is proportional to the noise level (NL). In addition, the accuracy of the results depends on various factors such as the signal character, filtering method or cut off frequency. In particular, coupled terms in multimode systems show larger differences compared to the true value when measured in an environment with a high NL. The iterative least square (ILS) method was proposed to reduce these errors that occur under a high NL, and has been verified in previous research. However, the ILS method might be sensitive to the signal processing, including the determination of cutoff frequency. This paper focused on improving the accuracy of the ILS method, and proposed the modified ILS (MILS) method, which differs from the ILS method by the addition of a new calculation process based on correlation coefficients for each degree of freedom. Comparing the results of these systems with those of a numerical simulation revealed that both ILS and the proposed MILS method provided good prediction of the dynamic properties of the system under investigation (in this case, the damping ratio and damped frequency). Moreover, the proposed MILS method provided even better prediction results for the coupling terms of stiffness and damping coefficient matrix.

키워드

참고문헌

  1. Chen, A., He, X. and Xiang, H. (2002), "Identification of 18 flutter derivatives of bridge decks", J. Wind Eng. Ind. Aerod., 90(12), 2007-2022. https://doi.org/10.1016/S0167-6105(02)00317-3
  2. Chowdhury, A.G. and Sarkar, P.P. (2003), "A new technique for identification of eighteen flutter derivatives using a three-degree-of-freedom section model", Eng. Struct., 25(14), 1763-1772. https://doi.org/10.1016/j.engstruct.2003.07.002
  3. Chun, N.H. (2011), "System identification of flutter derivatives extraction with independent variables", M.S. Dissertation, Korea University, Seoul.
  4. Fuyou, X., Xuyong, Y. and Zhe, Z. (2016), "Insight into coupled forced vibration method to identify bridge flutter derivatives", Wind Struct., 22(3), 273-290. https://doi.org/10.12989/was.2016.22.3.273
  5. Ghilani, C.D. and Wolf, P.R. (2006), Adjustment Computations: Spatial Data Analysis, John Wiley and Sons, Inc, Hoboken, New Jersey, USA.
  6. Hwang, Y.C., Kim, H.K., Cha, S.H. and Lee, H.S. (2014), "New excitation technique for the identification of flutter derivatives", Proceedings of the 2014 World Congress on Advances in Civil, Environmental, and Materials Research, Busan, August.
  7. Jakobsen, J.B. and Hjorth-Hansen, E. (1995), "Determination of the aerodynamic derivatives by a system identification method", J. Wind Eng. Ind. Aerod., 57, 295-305. https://doi.org/10.1016/0167-6105(95)00006-D
  8. James, H.M., Ronald, W.S. and Mark, A.Y. (2003), Signal Processing First, Prentice Hall, Upper Saddle River, New Jersey, USA.
  9. Sarkar, P.P. (1992), "New-identification methods applied to the response of flexible bridges to wind", Ph.D. Dissertation, MD: The Johns Hopkins University, Baltimore.
  10. Sarkar, P.P., Caracoglia, L., Haan, Jr. F.L., Sato, H. and Murakoshi, J. (2009), "Comparative and sensitivity study of flutter derivatives of selected bridge deck sections, Part 1: Analysis of inter-laboratory experimental data", Eng. Struct., 31(1), 158-169. https://doi.org/10.1016/j.engstruct.2008.07.020
  11. Sarkar, P.P., Jones, N.P. and Scanlan, R.H. (1992), "System identification for estimation of flutter derivatives", J. Wind Eng. Ind. Aerod., 41-44, 1243-1254.
  12. Scanlan, R.H. and Tomko, J.J. (1971), "Airfoil and bridge deck flutter derivatives", J. Eng. Mech. Div., ASCE, 97(6), 1717-1733.
  13. Simiu, E. and Scalan, R.H. (1996), Wind Effects on Structures, John Wiley and Sons, Inc., Hoboken, New Jersey, USA.
  14. Xu, F., Zhu, L., Ge, X. and Zhang, Z. (2014), "Some new insights into the identification of bridge deck flutter derivatives", Eng. Struct., 75, 418-428. https://doi.org/10.1016/j.engstruct.2014.06.015

피인용 문헌

  1. Determining minimum analysis conditions of scale ratio change to evaluate modal damping ratio in long-span bridge vol.22, pp.1, 2017, https://doi.org/10.12989/sss.2018.22.1.041