Output-only Techniques Research Articles

The paper resumes the activity of the Mechanical Department dynamics group around the Z24 benchmark used within the framework of the COST F3 Action; a miscellany of techniques including advanced signal processing, FE modelling and up-dating techniques have been used for this purpose. The first task of the work is the identification aspect; this target has been achieved by adopting output-only techniques such as RDT-ITD, ARMAV and CVA methods. In the Z24 case, the most interaction-free algorithm has been chosen, which was demonstrated to be the CVA technique; hence, only the results from this approach are proposed. Two methods are also proposed to choose the most convenient size in the CVA technique, one being based on analytical considerations of the condition number of the Hankel matrix, the other using the MAC approach. In terms of up-dating procedures, the well-known method of sensitivity analysis, based on a shell Finite Element Model has been adopted; the first task of the up-dating procedure developed in the paper has been devoted to tune the FEM on the undamaged bridge; this task is fundamental in preparing a correct model for further procedures investigating in the progressive damage direction.

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