Harnessing Adaptive Bistable Stiffness Inspired by Hair- Cell-Bundle Structure in Human Cochlea

Abstract

Abstract This study presents an initial study on the adaptive bistable stiffness of hair cell bundle structure in a human cochlea and aims to harness its bistable nonlinearity that features a negative stiffness region. Typically, hair cell bundle structures inside the human auditory system comprise a conical bundle structure constituting multiple tiny long cylinders called Stereocilia. Their primary function is to send electrical impulse signals to the brain in response to the vertical oscillation produced by the travelling wave propagation on the basilar membrane of the cochlea and to shift the region of better sensitivity through their mechanical adaption capability. In this study, the harmonic balance method was employed to understand the amplifying of the movements of hair cells over broad frequency ranges, and hair cell’s dynamic behaviors induced by bistable stiffness characteristics are projected on phase diagrams, and Poincare maps concerning the bifurcation. In this study, we investigate the nonlinear frequency responses of the hair cell bundle structure, deducing that the transferred sound signals can be significantly amplified, as observed in the super- and subharmonic response regimes. This study offers promising potential engineering applications to harness adaptive bistable stiffness.