The Boundary Element Method for Plate Analysis

It is observed that the amplitude of the vibrations increases as the external frequency $\mathrm{\Omega }$ approaches the natural frequency. However, the amplitude curves of the nonlinear problem move to the right, indicating a hardening nonlinear behavior, while two stable solutions are observed for some values of the excitation frequency. Moreover, due to the viscoelastic material, the vibrations are bounded contrary to the linear membrane problem. Fig. 5.19 presents the amplitude-frequency curves for various values of the viscous parameter $\mathit{\eta }$. The amplitude of ...