Nonlinear vibration response of a rectangular sheet under harmonic forced excitation in three-dimensional uniform flow: Influence of excitation amplitudes on frequency response

Thin, flexible plates (sheets) are used in numerous industrial applications. As these sheets are subjected to fluid flow during the manufacturing process, violent vibrations may occur in the sheets owing to external disturbances, which may cause serious damage to the sheets. Thus, it is crucial to clarify the detailed vibration characteristics of the sheet in a fluid flow to avoid or suppress vibrations. In this study, the influence of excitation amplitudes on the frequency response of a sheet was investigated in detail for various flow velocities to gain a deeper understanding of the nonlinear aspect of this problem through both experiments and nonlinear analysis. In the experiments, harmonic displacement excitation was applied at the leading edge of the sheet in a vertical wind tunnel. The influence of the excitation amplitudes on the frequency response was investigated. For the nonlinear analysis, a nonlinear fluid-structure interaction model considering the influence of harmonic displacement excitation was developed to investigate the vibration response. The frequency response curves exhibit softening-type nonlinearity for relatively low flow velocities, whereas frequency response curves exhibit hardening-type nonlinearity for relatively high flow velocities in the experiments. In contrast, the frequency response curves exhibit the softening-type nonlinearity regardless of the flow velocity in the nonlinear calculations based on the potential flow.(c) 2023 Elsevier Ltd. All rights reserved.