Karhunen-Loeve (K-I,) or proper orthogonal decomposition modes are used to
discretize the dynamics of a four-bay linear truss. This is achieved by def
ining global K-L modal amplitudes and employing the orthogonality relations
between K-L modes that are inherent in the K-L decomposition. It is found
that the K-L-based low-order models can capture satisfactory the transient
dynamics of the truss, even when only a limited number of them is used for
the order reduction. A comparison between the exact and low-order dynamics
in the frequency domain reveals that the low-order models capture the leadi
ng resonances of the truss. A series of experiments with a practical three-
bay truss is then performed to validate the theoretical K-L decomposition.
A comparison between theory and experiment indicates agreement between the
predicted and realized dominant K-L mode shapes, but less so in the higher-
order modes. The reasons for this discrepancy between theory and experiment
are discussed, and possible applications of the K-L-based order reduction
to passive and active control of practical large-scale flexible systems are
outlined.