Optimization of vibration characteristics and directional propagation of plane waves in branching ligament structures of wind models

Abstract

To achieve multi-frequency vibration suppression and wave propagation modulation, eight branching ligament structures for wind models are proposed. Using lattice theory, dynamical model and finite element release method, the structures are verified to have multi-frequency bandgaps. By attaching a solid disc at the center of the model, the bandgap coverage of the structure is improved and the bandgap frequency is reduced. The modal analysis shows that the vibration of branch ligaments and border ligaments has a suppression effect on elastic waves. The phase constant surface, phase velocity and wave propagation direction plots at specific frequencies are calculated to verify the directional and regional nature of wave propagation. And the good correspondence of group velocity and wave propagation finite element simulation results at specific frequencies. Finally, the calculated bandgap frequency range is compared with the vibration transfer function, and the two agree well. And the stress cloud diagram also shows that the optimized structure has an excellent vibration suppression capability. The innovatively designed structure has the combined advantages of light weight, ease of fabrication, wide frequency and low frequency vibration control, while the integrated in-plane wave analysis provides the theoretical basis for structural optimization.

Keywords

• Vibration attenuation
• Wave propagation
• Acoustic metamaterials
• Group velocity
• Stress fraction