A direct method for model updating with incomplete measured data and without spurious modes

This paper presents a new method for finite element matrix updating problem in an undamped model. This method has a computationally convenient feature of handling the difficulty of the incomplete measured data in an algorithmic way without using standard modal expansion or reduction techniques. The completed eigenvector matrix is such that it is mass normalised with respect to the analytical mass matrix. The method is also capable of preserving the large number of eigenvalues and eigenvectors of the finite element model that are not affected by updating. The latter has an effect of preventing the appearance of spurious modes in the frequency range of interest, which is a common concern with most direct updating methods.