THEORETICAL AND EXPERIMENTAL STUDY ON VORTEX-INDUCED VIBRATION SUPPRESSION BASED ON NONLINEAR TARGETED ENERGY TRANSFER

Flow-induced vibration of the structure widely occurs in many important engineering fields such as mechanical, aerospace, civil and petroleum. In order to prevent fatigue and failure of the engineering structures due to flow-induced vibrations, it’s necessary to do deep researches on stability, dynamic responses and vibration controls. In this paper, a nonlinear targeted energy transfer (NTET) model composed of linear springs and mass block is proposed. The passive control mechanism of nonlinear energy absorbers on the vortex-induced vibration of an elastically supported cylinder is investigated. Firstly, based on the energy method, the coupling dynamic equations for the nonlinear passive control on vortex-induced vibration of a cylinder are established. Then, experimental study is conducted by designing the nonlinear spring-mass configuration of NTET. Good agreements are obtained by comparing experimental results with theoretical predictions. Finally, the optimal parameters of the NTET for improving the control performance of vortex-induced vibrations are obtained. It is found that some NTET parameters such as mass, spring stiffness and spring prestress have significant impacts on the control performance. The results show that both the cylinder and NTET exhibit periodic steady-state vibration responses. Changes in the mass of NTET can significantly affect the coupling frequency of the system. In the case of no spring prestress, larger mass, lower stiffness of the NTET can produce a better vibration suppression. But when the spring prestress is increased, the nonlinear stiffness of the NTET becomes weak, resulting in a reduction of control effect on the vortex-induced vibration. Parametric analysis shows that with the enhancement of vortex-induced vibration control effect, the vibration amplitude of cylinder can be decreased while the NTET’s amplitude is gradually increased, indicating the improvement of the energy transfer efficiency. The present research results can provide very useful theoretical support and experimental data for efficiently designing control strategies on vortex-induced vibrations in engineering fields.