Impact vibration properties of locally resonant fluid-conveying pipes*

Fluid-conveying pipe systems are widely used in various equipments to transport matter and energy. Due to the fluid-structure interaction effect, the fluid acting on the pipe wall is easy to produce strong vibration and noise, which have a serious influence on the safety and concealment of the equipment. Based on the theory of phononic crystals, this paper studies the vibration transfer properties of a locally resonant (LR) pipe under the condition of fluid-structure interaction. The band structure and the vibration transfer properties of a finite periodic pipe are obtained by the transfer matrix method. Further, the different impact excitation and fluid-structure interaction effect on the frequency range of vibration attenuation properties of the LR pipe are mainly considered and calculated by the finite element model. The results show that the existence of a low-frequency vibration bandgap in the LR pipe can effectively suppress the vibration propagation under external impact and fluid impact excitation, and the vibration reduction frequency range is near the bandgap under the fluid-structure interaction effect. Finally, the pipe impact experiment was performed to verify the effective attenuation of the LR structure to the impact excitation, and to validate the finite element model. The research results provide a technical reference for the vibration control of the fluid-conveying pipe systems that need to consider blast load and fluid impact.