Modal testing and structural identification of a planar truss

This paper is an experimental investigation of the effect of damage on the vibration modes and frequencies of a steel planar truss. The damage is simulated by releasing an end constraint on certain structural members. Experiments showed that frequency changes induced by the damage are detectable, while, on the contrary, mode shapes turn out to be quite insensitive to the damage. The paper also discusses indeterminacy which has been met on structural identification from dynamic-test data