Abstract: With rigorous dynamic performance of mechanical products, it is important to identify dynamicparameters exactly. In this paper, a response surface plotting method is proposed and it can be applied to identifythe dynamic parameters of some nonlinear systems. The method is based on the principle of harmonic balancemethod (HBM). The nonlinear vibration system behaves linearly under the steady-state response amplitude, whichpresents the equivalent stiffness and damping coefficient. The response surface plot is over two-dimensional space,which utilizes excitation as the vertical axis and the frequency as the horizontal axis. It can be applied to observethe output vibration response data. The modal parameters are identified by the response surface plot as linearityfor different excitation levels, and they are converted into equivalent stiffness and damping coefficient for eachresonant response. Finally, the HBM with first-order expansion is utilized for identification of stiffness and dampingcoefficient of nonlinear systems. The classical nonlinear systems are applied in the numerical simulation as theexample, which is used to verify its effectiveness and accuracy. An application of this technique for nonlinearityidentification by experimental setup is also illustrated.

Key words: structural nonlinearity, parameter identification, equivalent stiffness and damping, response surfaceplot