A COMPARISON OF SENSITIVITY AND RESPONSE FUNCTION BASED UPDATING TECHNIQUES

摘要

This paper deals with the updating of the finite element model of an L-plate formed by two pieces connected by a series of spot welds. Experimental data were acquired for five nominally-identical specimens and it was observed that significant dynamic behaviour discrepancies existed between these specimens. A reference structure was selected so that the initial correlation of the theoretical and experimental models was acceptable and a full updating exercise was conducted using both the response function and inverse eigen sensitivity methods. Although significant improvements were obtained in both cases, it was found that the success of the updated models depended very heavily on the parameters chosen such as the selection and number of the frequency points in response function updating and the selection of modes to be included as well as the balancing of the sensitivity matrix in sensitivity based updating. A detailed comparison of the updated models was undertaken with particular emphasis on predicted response functions and the success of the updated models was assessed using a number of model quality parameters, some defined in this study. Also, as in previous investigations, it was found that the updated model was not unique since several satisfactory models could be obtained by changing the choice of updating parameters.