THE USE OF ANTIRESONANCES FOR ROBUST MODEL UPDATING

✍ Scribed by W. D'AMBROGIO; A. FREGOLENT

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 222 KB
• Volume: 236
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1999.2987

✦ Synopsis

In this paper, an updating technique that includes antiresonances in the de"nition of the output residual is considered. Antiresonances are not a global system property, but are typical of each frequency response function (FRF), thus allowing the residual vector to be enlarged with data identi"ed from additional FRFs. However, antiresonance information is not independent of mode shape information; it is rather an alternative, which is preferable for several reasons. Antiresonances can be identi"ed from experimental FRFs with much less error than mode shapes; furthermore, correlation between test and analysis antiresonances is a good index of the correlation between test and analysis FRFs. In the implementation of the technique, matching problems arise whenever antiresonances identi"ed from transfer FRFs are used; unlike the situation for point FRFs, the distribution of antiresonances may be signi"cantly altered by small changes in the structural model. Such problems may be circumvented by restricting the experimental database to point FRFs; in this case, the procedure is quite robust and excellent results are obtained, although it is necessary to plan experimental testing di!erently from the usual modal testing, with possible impact on related costs. For this reason, a procedure to deal with transfer FRFs by establishing a correlation between test and analysis FRFs at antiresonances using frequency domain assurance criterion (FDAC), is also evaluated. The procedure is not very robust and requires special attention to give acceptable results.