FINITE-ELEMENT MODEL UPDATING USING FREQUENCY-RESPONSE FUNCTION DATA .2. CASE-STUDY ON A MEDIUM-SIZE FINITE-ELEMENT MODEL

This work reports findings from a case study which is aimed at updatin g a medium-size finite element model using frequency response function (FRF) data. The numerical stability of the method and its applicabili ty to true measured FRF data were investigated in the case of a plate- beam structure which was modeled using about 500 dof. The initial fini te element model of the structure was found to be in fairly good agree ment with measured data, a feature which allowed a systematic evaluati on of various factors affecting the quality of model updating. After s everal attempts, it was possible to update the initial FRFs so that th ey matched the measured ones within engineering accuracy. However, the non-uniqueness of the updated model became apparent since it was poss ible to find several such models, the FRFs of each of which satisfied the basic matching criterion.