Abstract: Due to wide-ranging and successful aplication of linear modal analysis (LMA), not only in the structural dynamics, but practically in all areas of natural and engineering sciences, its simple concept strives to extends to nonlinear dynamical systems. This has led to the formulation of nonlinear modal analysis (NMA), which has a potential to become powerful tool in the analysis of real dynamic systems. This paper presents a comparison of simple linear and nonlinear systems, and the concept of nonlinear normal modes (NNM). For realistic estimation of dynamical parameters experimental modal analysis is neccessary, which can then, in combination with nonlinear analysis, give real results.
Keywords: linear modal analysis, nonlinear modal analysis, nonlinear normal modes, experimental modal analysis