CONSTRUCTING A FINITE-ELEMENT MODEL OF A VIBRATORY ROD FROM EIGENDATA

The finite element model, based on linear shape functions, for rods under longitudinal vibrations, consists of mass and stiffness matrices which are both tri-diagonal. It is shown that this model can be constructed from a single eigenvalue and two eigenvectors. However, for a large model order, the construction based on these data is sensitive to perturbations. The sensitivity of the model can be decreased by using overdetermined data. The results can be applied to evaluate experimental finite element models for rod-like structures from vibration test data. © 1994 Academic Press Limited.