Shipborne precision instruments present vibration under wave loadings, especially in the harsh sea state, which deteriorates the instrument function and even causes failure. Inspired by the bionics dynamics, this study proposes an adaptive bio-inspired isolator for mitigating the random wave-induced vibration. The conceptual design of the proposed isolator is constructed by embedding an MRE-based device into a limb-like bio-inspired structure, which presents controllable high-static-low-dynamic stiffness property. The proposed system could fulfill tuning capability for effective vibration mitigation in low-frequency excitations. The theoretical modeling is developed and the static analysis of the proposed isolation system is studied. The dynamic equation of proposed isolation system under regular and random wave loadings is established and solved by the harmonic balance method. The influences of key geometrical and field-controllable parameters on the proposed isolation system characteristics (e.g., displacement transmissibility, acceleration response and vibration peak) are investigated and the tunable frequency-shift properties are presented. The results demonstrate that the adaptive MRE-based bio-inspired isolation system can effectively suppress the objective’s dynamic responses under wave-induced loadings in various primary frequencies. Additionally, the proposed isolation system obviously outperforms the passive linear isolation system in decreasing objective’s displacement and acceleration. This study indicates that the proposed MRE-based adaptive bio-inspired isolation system could provide a potential method for vibration isolation tuning in random low-frequency wave-induced vibration.
 

Magnetorheological elastomer (MRE), bio-inspired dynamics, semi-active control, nonlinearity, vibration mitigation.