FRF-based model updating using SMURF technique

Finite element (FE) method is a well-known technique in structural dynamic analysis. However, FE models may be inaccurate or even incorrect due to erroneous modeling, geometrical over-simplification or uncertainties in the element and joint properties. In contrast, modal models are generally considered to be correct or at least closely matching the actual dynamic behavior of a structure. Therefore, a model updating procedure should be introduced for adjusting the analytical model in order to reconcile theoretical and experimental results. In this paper, a new FRF-based model updating method is proposed based on the Structural modification using experimental frequency response functions (SMURF) method. It is demonstrated that the proposed method updates the parameters accurately using just a few frequency response functions from the mis-modeled regions. A 12-DOF mass-spring system is considered as a test case in a simulated experiment. The convergence of the method and its capacity to improve the accuracy of the FE model are evaluated. Moreover, the paper considers the effect of the number of modes, the frequency range of interest used in the calculations as well as the coordinate incompleteness and noise on the quality of the updated model. The updated models are compared in terms of the predicted natural frequencies, mode shapes and frequency response functions.