Modal Truncation

In actuality: FUE = FU + F'U

and FDE = FD + F'D

The problem is then

[(FD-FU) + (F'D-F'U)] [L] = 0

or (FD-FU) L + (F'D-F'U) L = 0

what we solve is just the first term, therefore for the approach to give accurate values of L it is necessary that

FD - FU ?? F'D-F'U

i.e. Damage must have a significantly larger effect on the identified modes than in the modes that belong to the truncated space.

contributions from

unidentified modes

Previous slide

Next slide

Back to first slide

View graphic version