A direct model updating method using added known stiffness

In order to solve the problem of insufficient measured modes in the dynamic model updating, a direct model updating method using added known stiffness components is proposed. In this method, a revised structure is obtained by adding the known stiffness components to the original structure, and then the measured modal parameters of both the original structure and the revised structure are used to update the dynamic model. For a definite set of parameters to be updated, the proposed method can be utilized to increase the number of the modal parameters available in the model updating procedure, thus the orders of the required measured modes can be largely decreased. Two model updating examples for a 25 degree-of-freedom mass-spring model and a straight wing model are demonstrated numerically to verify the feasibility of the updating algorithm. The results show that using the proposed method, good updating accuracy can be achieved with only a few numbers of measured modal parameters.