Flexoelectric energy dissipating mechanism for multi-impact protection

Traditional impact protection structures (IPSs) dissipate impact energy according to the plastic dissipation mechanism, which is only effective for single impacts due to the irreversible deformation of structures. To achieve multi-impact protection, this paper proposes a novel chiral periodic structure with the deformation self-recovery function and the high energy conversion efficiency based on the flexoelectric mechanism. A theoretical model is formulated on the electromechanical responses of a flexoelectric beam under rotational boundaries. The equivalent stiffness and damping characteristics are subsequently derived to construct the electromechanical responses of the structure under constant velocity and mass impacts. Discussions are addressed for the influence of the structural scale effect and resistance on the electromechanical responses. The results show that the energy conversion efficiency increases by 2 to 3 orders of magnitude, reaching as high as 85.3%, which can match well with those of structures reported in the literature based on the plastic energy dissipating mechanism.