Linear parameter estimation for multi-degree-of-freedom nonlinear systems using nonlinear output frequency-response functions

The Volterra series approach has been widely used for the analysis of nonlinear systems. Based on the Volterra series, a novel concept named nonlinear output frequency-response functions (NOFRFs) was proposed by the authors. This concept can be considered as an alternative extension of the classical frequency-response function for linear systems to the nonlinear case. In this study, based on the NOFRFs, a novel algorithm is developed to estimate the linear stiffness and damping parameters of multi-degree-of-freedom (MDOF) nonlinear systems. The validity of this NOFRF-based parameter estimation algorithm is demonstrated by numerical studies.