Direct Eigenstructure Assignment for Model Updating

A direct updating approach for stiffness and damping matrices based on eigenstructure assignment is presented. The approach (which preserves symmetry, connectivity, and constraints imposed by static equilibrium) computes the corrections as the sum of two parts: the first ensures the modal data are exactly satisfied; and the second, without shifting the identified part of the spectrum, satisfies the constraints exactly for consistent modal data and in a least-square sense otherwise.