Bio-inspired passive actuator simulating an abalone shell mechanism for structuralcontrol

Abstract

An energy dispersion mechanism called ‘sacrificial bonds and hidden length’, which is foundin some biological systems, such as abalone shells and bones, is the inspiration fornew strategies for structural control. Sacrificial bonds and hidden length cansubstantially increase the stiffness and enhance energy dissipation in the constituentmolecules of abalone shells and bone. Having been inspired by the usefulness andeffectiveness of such a mechanism, which has evolved over millions of years andcountless cycles of evolutions, the authors employ the conceptual underpinnings ofthis mechanism to develop a bio-inspired passive actuator. This paper presents afundamental method for optimally designing such bio-inspired passive actuators forstructural control. To optimize the bio-inspired passive actuator, a simple methodutilizing the force–displacement–velocity (FDV) plots based on LQR control isproposed. A linear regression approach is adopted in this research to find theinitial values of the desired parameters for the bio-inspired passive actuator. Theillustrative examples, conducted by numerical simulation with experimental validation,suggest that the bio-inspired passive actuator based on sacrificial bonds and hiddenlength may be comparable in performance to state-of-the-art semi-active actuators.