Design parameter oriented model updating method using additional masses

As there are too many unknown variables which need to be updated for the model updating method using additional masses, the updating equation conducted by this method is an underdetermined equation, and the updating accuracy cannot meet the requirements of engineering applications. A design parameter oriented model updating method was presented to improve the accuracy of this method. Taylors series of the system matrices expanded with respect to design parameters were adopted, and the sensitivity influence matrices of stiffness and mass were derived, then updating objects were converted to design parameters. A straight wing model and a step section beam were performed as numerical examples to verify the improved method. For the two examples, local stiffness errors in the range of 30% to 50% were introduced into the initial finite element models. The calculation errors obtained by the updated finite element models were less than 1% for both examples. The results showed that the presented method can largely reduce the number of unknown variables, and just limited measured modes were needed, and the updating accuracy was also better than that of the original method, and furthermore, the physical indications of updating results were clearer than that of the original method.