Simultaneous identification of structural physical parameters and input based on dynamic response sensitivity

A new method was proposed to simultaneously identify structural physical parameters and input from several dynamic responses of a structure based on dynamic response sensitivity. The input forces on the structure were represented by using orthogonal polynomial approximation, and the sensitivity of the structural dynamic response with respect to the orthogonal coefficients of input forces and the physical parameters of the structure was derived analytically. The identification equation was set up and was solved with the damped least-squares method to simultaneously identify input forces and structural parameters. A five-story plane frame and a nine-bay three-dimensional frame were taken as examples for validating the proposed method, respectively. Numerical simulations with noisy measured accelerations and initial model errors showed that the proposed method could accurately identify the input forces and detect the changes of structural physical parameters caused by structural local damages.