An low-frequency vibration isolation structure inspired by ladybird sheath

The circular sheath wing structure of the ladybird provide excellent low-frequency vibration attenuation based on mortise and tenon construction. However, the mortise and tenon structure is prone to wear and tear, and also has higher requirements for machining and installation, and is characterized by low efficiency of energy consumption by intermittent friction. A bio-inspired structure is inspired by the energy dissipation mechanism of ladybird sheath wings. The mortise and tenon structure is improved by extruding curved guiding friction plates to realize the continuous friction energy dissipation mechanism. To reduce the machining and installation difficulties, three pairs of 1/4 curved beams are utilized instead of the hemispherical structure of the ladybug. Viscoelastic rubber and permanent magnet repulsion mechanism are introduced to realize the purpose of multiple vibration isolation. Mechanical models and finite element analyses were established for the units of arc beams, permanent magnetic repulsion, and rubber. Based on the theoretical calculations and simulation results, the effectiveness of the structure and the influence of structural parameters on the output performance are inferred. A low-frequency shock vibration experimental system was set up to investigate the isolation effect of the bio-inspired structure employing low-frequency shock vibration from 0.2 to 5 Hz. The experimental results show that for vibration below 5 Hz, the vibration isolation efficiency of the bio-inspired structure can reach 94 % by choosing three pairs of arc beams of 0.2 mm thickness with 48 mm silicone rubber pads and four pairs of permanent magnets.