Developing coexisting traveling and standing waves in Euler-Bernoulli beams using a single-point excitation and a spring-damper system

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Department of Mechanical Engineering-Engineering Mechanics


In the inner ear, the Basilar Membrane (BM) and inner hair cells work to transduce acoustic waves into electrical signals; of these, the BM is the structural membrane that carries the acoustic information as traveling structural waves. These waves propagate from the base of the cochlea towards its apex. The helicotrema is the main component of the cochlea's apex, which prevents the waves from traveling back from the apex to the base. Due to this unique characteristic of the BM, humans are able to hear continuous acoustic signals without any reflection and overlap of acoustics. The work herein is inspired by this biological behavior and seeks to understand and replicate such behavior in a passive manner in basic structures. This feature of the inner ear leads us to study the dynamics of a uniform beam connected to a spring-damper system as a passive absorber, in order to understand some of the observed phenomenological behaviors of the basilar membrane. The location of the spring-damper system divides the beam into two dynamic regions: one which exhibits non-reflecting traveling waves and the other with standing waves. In this paper, traveling waves co-existing with standing waves in the two distinct regions of the structure and are realized analytically, numerically, and experimentally. The results of this work can be used in various applications such as vibration energy harvesting, particle transportation, vibration suppression and control, and in exploring possible explanations of the functionality of the helicotrema in the cochlea.

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Journal of Sound and Vibration