Reverse Design of a Novel Coupling Strut for Vibration Attenuation in the Helicopter Cabin

Helicopter gearbox support strut is one of the main research objects in field vibration and noise control helicopter cabins. Aiming to further widen attenuation range traditional Bragg periodic struts, a novel type Local resonance (LR)/Bragg coupling with graded parameters as well reverse design method proposed. Combined spectral element (SEM) transfer matrix (TMM), analytical expression transform relationship longitudinal vibrations through yielded. The impacts different on boundaries bandgaps are explored according results simulation analysis. On this basis, gradient determined, then all unknown structural can also be determined. Compared struts LR/Bragg non-graded parameters, presented has an obvious advantage widening low-frequency below 500 Hz.