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Identification of Mode Shape by Fitting Cross power Spectra under Unknown Excitation(PDF)

《南京理工大学学报》(自然科学版)[ISSN:1005-9830/CN:32-1397/N]

Issue:
2000年02期
Page:
117-120
Research Field:
Publishing date:

Info

Title:
Identification of Mode Shape by Fitting Cross power Spectra under Unknown Excitation
Author(s):
ShenFan ZhengMin BaoMing
Institute of Vibration Engineering Research,NUAA,Nanjing 210016
Keywords:
cross-pow er data f it t ing modal analysis ambient excitat ion complex exponential method
PACS:
O324
DOI:
-
Abstract:
The cross-correlat ion functions is applied to PRCE method to ex tract the natural frequencies and damping f rom output only under the w hite-noise ex citation, but the mode shape can. t be determined. This paper gives a theoretical formulat ion for the ext ract ion of mode shape by f it t ing the cross-pow er spectra of the output s and a cantilever beam is analysed. The results show that the present method can ident ify the mode shape accurately and complement the use of PRCE under unknow n ex citat ion condit ion.

References:

1 Bao Z W, Ko J M. Determination o f modal parameters of tall buildings w ith ambient vibr at ion measurements. The International Journal of Analytical and Exper imental Modal Analysis, 1991( 1) : 57~ 68
2 Hermans L, Mathieu L. Modal parameter extr action from in-operation data. Proceeding s of the 15t h SEM I nternational Modal Analysis Co nference. Bethel: Society for Exper iment Mechanics Inc, 1997. 531~ 539
3 James Ó G H, Carne T G. The natural excitation technique ( NExT) for modal parameter extraction from operating structure. The International Journal of Analy tical and Exper imental Modal Analysis, 1995, 10( 4) : 260~ 277

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Memo:
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Last Update: 2013-03-25