Analytical model improvement using frequency response functions

In recent years, a number of different methods have been developed in order to update an analytical structural dynamics model using the limited data which can be obtained from vibration tests. The majority of these methods are based on correlation between the analytical and measured modal data and, in most cases, spatial completeness of the measured co-ordinates is critical. In this paper, a new method is presented which tackles the model updating problem by using an incomplete set of measured FRF data directly. It is shown that model updating methods based on modal data are, essentially, particular cases of the present generalised method in which FRF data at resonance frequencies only are employed. The advantages of using FRF data (over modal data) to update an analytical model are demonstrated. Special attention is given to the application of the method to the case where both measured modes and co-ordinates are incomplete. The practical applicability of the method is assessed based on the GARTEUR structure which has been used in a Europe-wide correlation exercise.