고유진동수 이용 손상추정법과 모드형상 이용 손상추정법에 의한 PSC 보의 비파괴 손상검색

Nondestructive Damage Detection in PSC Beams : Frequency-Based Method Versus Mode-Shape-Based Method

  • 김정태 (정회원·부경대학교 해양공학과) ;
  • 류연선 (정회원·부경대학교 해양공학과) ;
  • 조현만 (정회원·부경대학교 해양공학과 시간강사)
  • 발행 : 2002.03.01

초록

PSC 보의 비파괴 손상검색을 위한 고유진동수 이용 손상추정법과 모드형상 이용 손상추정법을 제시하였다. 먼저, 고유진동수의 변화를 사용하여 손상의 위치를 예측하는 알고리즘과 고유진동수 1차 섭동 이론에 근거하여 균열크기를 예측하는 알고리즘을 요약하였다 다음으로, 모드형상의 변화로부터 모드민감도의 변화를 감지하고 이를 통해 손상의 위치와 크기를 추정하는 손상지수 알고리즘을 요약하였다. PSC 보의 유한요소모델을 사용하는 수치실험을 통해 고유 진동수 이용 손상추정법과 모드형상 이용 손상추정 법의 정확성을 검증하였다. 분석결과 두 방법 모두 실험 대상 구조에 도입된 균열의 위치를 정확하게 예측하였으며 균열의 크기를 비교적 근사하게 예측하였다.

A methodology to nondestructively locate and estimate size of damage in beam-type structures using a few natural frequencies or a few mode shapes is presented. A damage-localization algorithm to locate damage from changes in natural frequencies and a damage-sizing algorithm to estimate crack-size from natural frequency perturbation are outlined. A damage index algorithm to localize and estimate severity of damage from monitoring changes in mode shapes is outlined. The frequency-based method and the mode-shape-based method are evaluated for several damage scenarios by locating and sizing damage in PS concrete beams lot which a few natural frequencies and mode shapes are generated from finite element models. The result of the analyses indicates that the two methods correctly localize and closely estimate the size of the crack simulated in the test beam.

키워드

참고문헌

  1. Rytter, A., 'Vibration Based Inspection of Civil Engineering', Ph.D. Dissertation, Uni- versity of Aalborg, Denmark, 1993
  2. Vandiver, J. K., 'Detection of Structural Failures on Fixed Platforms by Measurement of Dynamic Responses', Proc. of 7th Annual Offshore Technology Conference, Houston, Texas, Paper 2267, 1975
  3. Crohas, H., and Lepert, P., 'Damage Detection Monitoring Method for Offshore Platforms Is Field Tested', Oil and Gas J., Vol. 80, No. 8, 1982
  4. Cawley, P., and Adams, R. D., 'The Location of Defects in Structures from Measurements of Natural Frequencies', J. Strain Analysis, Vol. 14, No. 2, 1979, pp.49-57 https://doi.org/10.1243/03093247V142049
  5. Pandey, A. K., Biswas, M., and Samman, M. M., 'Damage Detection from Changes in Curvature Mode Shapes', Journal of Sound and Vibration, Vol. 145, No. 2, 1991, pp. 321-332
  6. Chance, J., Tomlinson, G. R., and Worden, K., A Simplified Approach to the Numerical and Experimental Modeling of the Dynamics of a Cracked Beam, Proc. of the 12th Int. Modal Analysis Conference, Honolulu, Hawaii, Vol. 1, 1994, pp.778-785
  7. Stubbs, N., and Osegueda, R., 'Global Non-destructive Damage Evaluation in Solids', Int J. Analytical and Experimental Modal Analysis, Vol. 5, No. 2, 1990, pp.67-79
  8. Wu, X., Ghaboussi, J., and Garrett, J. H., 'Use of Neural Networks in Detection of Structural Damage', Computers and Structures, Vol. 42, No. 4, 1992, pp.649-659 https://doi.org/10.1016/0045-7949(92)90132-J
  9. Kaouk, M., and Zimmerman, D. C., 'Structural Damage Assessment Using a Generalized Minimum Rank Perturbation Theory', AIAA J., Vol. 32, No. 4, 1994, pp.836-842 https://doi.org/10.2514/3.12061
  10. Stubbs, N., Kim, J. T., and Topole, K., 'The Effect of Model Uncertainty on the Accuracy of Global Nondestructive Damage Detection in Structures', Computational Stochastic Mechanics, eds. P.D. Spanos and C. A. Brebbia, Elsevier Applied Science, London, 1991, pp.125-136
  11. Ostachowicz, W. M. and Krawczuk, M., 'Vibration Analysis of a Cracked Beam', Computers & Structures, Vol. 36, No. 2, 1990, pp.245-250 https://doi.org/10.1016/0045-7949(90)90123-J
  12. Sundermeyer, J. N., and Weaver, R. L., 'On Crack Identification and Characterization in a Beam by Nonlinear Vibration Analysis', TAM Report No. 74, UILU-ENG-93-604, Univ. of Illinois, 1993
  13. Kim J. T., 'Assessment of Relative Impact of Model Uncertainty on the Accuracy of Nondestructive Damage Detection in Struc- tures', Ph.D. Dissertation, Texas A&M University, U.S.A., 1993
  14. Chen, J., and Garba, J.A., 'On-Orbit Damage Assessment for Large Space Structures', AIAA Journal, Vol. 26, No. 9, 1988, pp.1119-1126 https://doi.org/10.2514/3.10019
  15. Pandey A. K., and Biswas, M., 'Damage Detection in Structures using Changes in Flexibility', Journal of Sound and Vibration, Vol. 169, 1994, pp.3-17 https://doi.org/10.1006/jsvi.1994.1002
  16. Stubbs N., and Kim, J. T., 'Damage Localization in Structures Without Baseline Modal Parameters', AIAA Journal, Vol. 34, No. 8, 1996, pp.1649-1644
  17. Farrar, C. R., and Jauregui, D. A., 'Comparative Study of Damage Identification Algorithm Applied to a Bridge: I. Experiment', Smart Mater. Struct., Vol. 7, 1998, pp.704- 719 https://doi.org/10.1088/0964-1726/7/5/013
  18. Kim, J. T., and Stubbs, N., 'Improved Vibration-Based Damage Identification Method', Vol. 12, No. 3, 1999, pp.331-343
  19. Kim, J. T., 'Experimental Verification of Nondestructive Crack Detection Model Using a Few Natural Frequencies', Journal of the Computational Structural Engineering Institute of Korea, Vol. 12, No. 2, 1999, pp.149-159
  20. Gudmunson, P., 'Eigenfrequency Changes of Structures due to Cracks, Notches or Other Geometric Changes', J. Mech. Phys. Solids, Vol. 30, No. 5, 1982, pp.339-353 https://doi.org/10.1016/0022-5096(82)90004-7
  21. Kim, J. T., and Stubbs, N., 'Model Uncertainty and Damage Detection Accuracy in Plate- Girder Bridges', Journal of Structural En- gineering, ASCE, Vol. 121, No. 10, 1995, pp.1409-1417 https://doi.org/10.1061/(ASCE)0733-9445(1995)121:10(1409)
  22. Saiidi, M., Douglas, B., and Feng, S., 'Pre- stress Force Effect on Vibration Frequency of Concrete Bridges', Journal of Structural Engineering, ASCE, Vol. 120, No. 7, 1994, pp.2233-2241 https://doi.org/10.1061/(ASCE)0733-9445(1994)120:7(2233)