Structural parameter estimation accuracy in the presence of modeling error

A study on the significance of modeling error in parameter estimation for the purpose of structural identification (St-Id) is presented. This paper examines the impact of the uncertainty in a finite element model on the estimated parameters and the shape of two objective functions. Selected known parameters of a six-story shear building are systematically contaminated and labeled as uncertain parameters. The values of the objective functions are calculated using simulated incomplete modal data sets. The objective functions are plotted in 3D to visualize the error surface. St-Id is performed to verify the values of the parameter estimates at the global minimum. Additionally, the process of error propagation is investigated. It is concluded that parameter estimates can get contaminated to various degrees based on modeling error as well as measurement locations and type of error function used. Modeling error simulations prior to actual field-testing is highly recommended to determine the feasibility of nondestructive tests for successful St-Id.