4 - Memorial University of Newfoundland DAI

general agreement.
5. An investigatim into the effect of s member cracking suggested that
the Sl~eluml InlcgrZy Mclhod is limited because of the low sensitir
ily/resoiution regarding resonant frequcney versus eraeks. This, there-
for~, implies thal only major damages (i.e., primary structural element
lailurc) can be dokcled.
6. At each roaonant frequency, the structure deformed in a different man-
ner. ilcnce, the relative magnitudes between the various remnant f m
quencies should provide an indication of tho general location at which
the structure had b m weakened. The prima~y benefit of such a gs-
tem is that any damagorl mombcr which has a large influence on the
ati~Tnoas of a pnrticuinr mode of the structure will, obviously, rault in
as annlugous large change in the exdtstion frequency of that mode.
Thus, il is imperative that the stiffness characleristics of the atruc-
tore bc completely underrtaod; sa any large changes in the resonant
freguoncy of s specific mode may be localized.
7. Worn the thcorelicaiiy computed mode shapes, it was possible to ob-
serve lile effecl of damage on the most affected mode(r) fmm theshear-
iog of llre panel containing the damaged mcmbcr(s). Thia could not be
ailown experimentally, since it would require an array of transducers to
computc the mode shapes from the experimentaldata.
8. Esiimates of damping for the lat mode (from the wave induced vibra-
tions sludies) are lower than that obtained with the transient decay
tests. The values computed from the wave tests are: 2.02% and 2.4'196,