DOI QR코드

DOI QR Code

Equivalent Damping Ratio Based on Earthquake Characteristics of a SDOF Structure with an MR Damper

지진특성에 따른 MR감쇠기가 설치된 단자유도 구조물의 등가감쇠비

  • Published : 2008.01.20

Abstract

Seismic control performance of MR dampers, which have severe nonlinearity, varies with respect to the dynamic characteristics of an earthquake such as magnitude, frequency and duration. In this study, the effects of excitation characteristics on the equivalent linear system of a building structure with the MR damper are investigated through numerical analysis for artificial ground motions generated from different response spectrums. The equivalent damping ratio of the structure with the MR damper is calculated using Newmark and Hall's equations for ground motion amplification factors. It is found that the equivalent damping ratio of the structure with the MR damper is dependent on the ratio of the maximum friction force of the MR damper over excitation magnitude. Frequency contents of the earthquake ground motion affects the equivalent damping ratio of long-period structures considerably. Also, additional damping effect caused by interaction between the viscousity and friction of the MR damper is observed. Finally. response reduction factors for equivalent linear systems are proposed in order to improve accuracy in the prediction of the actual nonlinear response.

References

  1. Jung, H.-J., Spencer, Jr, B. F., Ni, Y. Q. and Lee, I.-W., 2004, 'State-of-the-art of Semiactive Control Systems Using MR Fluid Dampers in Civil Engineering Applications', Structural Engineering and Mechanics, Vol. 17, No. 3-4, pp. 493-526 https://doi.org/10.12989/sem.2004.17.3_4.493
  2. Spencer Jr., B. F., Dyke, S. J., Sain, M. K., Carlson, J. D., 1997, 'Phenomenological Model for Magnetorheological Dampers', Journal of Engineering Mechanics, Vol. 123, No. 3, pp. 230-238 https://doi.org/10.1061/(ASCE)0733-9399(1997)123:3(230)
  3. Jansen, L. M., Dyke, S. J., 2000, 'Semiactive Control Strategies for MR Dampers : Comparative study', Journal of Engineering Mechanics, Vol. 126, No. 8, pp. 795-803 https://doi.org/10.1061/(ASCE)0733-9399(2000)126:8(795)
  4. ATC, Seismic Evaluation and Retrofit of Concrete Buildings, ATC-40 Report, Applied Technology Council, Redwood City, California, 1996
  5. Vanmarcke, E. H., Gasparini, D. A., 1976, SIMQKE User's Manual and Document, Division of Advanced Environmental Research and Technology, MIT
  6. Clough, R. W., Penzien, J., 1993, Dynamics of Structures, McGrow-Hill, Singapore
  7. Newmark, N. M. and Hall, W. J., 1982, 'Earthquake Spectra and Design', Earthquake Engineering Research Institute, Berkeley
  8. Lee, S.-K., Min, K.-W., 2005, 'Study on the Shaking Table Testing Method Considering the Dynamic Soil-structure Interaction', Proceeding of Architectural Institute of Korea Annual Autumn Conference, Vol. 25, No. 1, pp. 15-18