Enhanced Vibration Attenuation via Structurally Engineered Frozen Mode Regime

As aircraft and instruments become more complex and precise, the need to manage vibrations becomes an issue of extreme importance as it is necessary to help maintain functionality and increase the lifespan of the object. We propose a mechanism to increase the attenuating properties of a one-dimensional phononic crystal through the geometric modification of the unit cell structure. These geometric modifications allow for the existence of a stationary inflection point (SIP) in the Bloch dispersion relation of the phononic crystal. At this frequency, the group velocity of the propagating solutions of the acoustic wave equation goes to zero, essentially trapping the wave inside the structure leading to near zero transmission through the crystal. This behavior allows for the absorption of the structure to scale nonlinearly with the length of the phononic crystal. The specific excitation frequency at which this effect occurs can be tuned by changing both material and geometric properties and is robust against any manufacturing defects and ambient temperature.