Parametric Identification Based on Pseudo-Tests

Optimal selection of artificial boundary conditions for model update and damage detection

“…This has been demonstrated experimentally in [15,21]. In [14], both the natural frequencies and mode shapes of the OCS are used in updating. The experimental study of the identification of OCS natural frequencies, reported in [21], demonstrated that OCS natural frequencies do indeed appear clearly as peaks in the OCS impedance spectra.…”

“…The method of artificial boundary conditions [13], or ''pseudo-tests'' [14] offers those benefits while avoiding some of their drawbacks. The theory of ABC originates in the concept of the omitted coordinate system (OCS) [15] which plays a central role in the underlying properties of advanced model reduction techniques and frequency domain updating; see for example, [16][17][18][19][20][21][22].…”

“…Note that column pivoting in conjunction with the QR method is effective for dealing with near-rank deficiency, and can improve numerical accuracy, so its use as a subset selection strategy does not compromise the numerical aspects of the problem. The use of the QR algorithm in the context of model updating with artificial boundary conditions (''pseudo-tests'') has also been explored in [14]. …”

Vibration Nodes, and the Cancellation of Poles and Zeros by Unit-Rank Modifications to Structures

“…The Appendix gives a thorough review of the``classical'' theory on unitrank adjustment of structural systems including the cases of modi®cation by a passive spring and an active feedback gain. Further information can be obtained from Lallement and Cogan [9] and Rade [10]. Ram and Blech [11] showed that when a system is modi®ed by adding a stiffness, k * , and a mass, m * , at a single co-ordinate then all of the natural frequencies above k à am à p will decrease whilst all those below k à am à p will increase.…”