Isolated substructure model updating based on local static test

For large-scale structures,measurement and identification of the whole structure are very difficult and the accuracy of the estimates is rarely reliable.In general,only some local substructure model is important and it is not necessary to update the whole structure.From such a viewpoint,the isolated substructure method for model updating and damage detection was introduced.It aims at updating local substructure element stiffness by using the static response at the corresponding substructure location of the whole structure.First,the isolated substructure was formed by applying virtual fixed supports(numerically and not physically) on the substructure boundaries to obtain the local flexibility matrix of the isolated substructure.Then a new flexibility perturbation method was used to modify the model of the isolated substructure,which can accurately compute the stiffness modification coefficients only by simple computation without any higher-order approximation or iteration.A plane truss structure was analyzed as a numerical example to verify the presented method.The results show that the substructure can be updated successfully by using the static displacement response at the corresponding substructure location even with 3% noise.