Parametric identification of nonlinear multiple degree-of freedom structural dynamic systems

The identification of linear structural dynamic systems has been dealt with extensively in the past studies. Identification methods for nonlinear structures have also been introduced in previous articles, including procedures based on the method of multiple scales, iterative and noniterative direct methods, and state space mappings. Here, a procedure based on multiple step integration methods for the solution of differential equations is applied to a simple two degrees of freedom system. RMS based noise is added to a simulated response in order to monitor the effects of measurement noise on the identification procedures. The input data is filtered before final processing in the identification algorithms. The multistep algorithm is compared with the iterative direct method on the basis of criteria such as accuracy, ease of use, and numerical efficiency.