Parameter Identification of Structural Nonlinearity by Using Response Surface Plotting Technique

Abstract

With rigorous dynamic performance of mechanical products, it is important to identify dynamic parameters exactly. In this paper, a response surface plotting method is proposed and it can be applied to identify the dynamic parameters of some nonlinear systems. The method is based on the principle of harmonic balance method (HBM). The nonlinear vibration system behaves linearly under the steady-state response amplitude, which presents 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 observe the output vibration response data. The modal parameters are identified by the response surface plot as linearity for different excitation levels, and they are converted into equivalent stiffness and damping coefficient for each resonant response. Finally, the HBM with first-order expansion is utilized for identification of stiffness and damping coefficient of nonlinear systems. The classical nonlinear systems are applied in the numerical simulation as the example, which is used to verify its effectiveness and accuracy. An application of this technique for nonlinearity identification by experimental setup is also illustrated.