Design and optimization of a novel locally resonant periodic strut for vibration and noise reduction in helicopter cabins

This article presents a novel locally resonant periodic strut to mitigate vibration and noise in helicopter cabins. Dual-resonator configurations in series and parallel combine local resonance and Bragg scattering, achieving broadband attenuation from 200 to 2000 Hz. Dynamic modelling based on the spectral element method and transfer matrix analysis reveals distinct low-frequency resonance bandgaps and mid-to-high-frequency Bragg bandgaps. The influences of key design parameters, including mass and stiffness ratios, are analysed to optimize bandgap characteristics. A genetic algorithm is employed to identify the global optimal design, significantly enhancing vibration isolation performance. Numerical simulations demonstrate that the proposed strut exhibits superior attenuation capabilities compared with conventional designs, underscoring its potential in advanced aerospace applications for noise and vibration control. It should be noted that the decoupling of stiffness- and mass-related parameters relies on an idealized assumption for theoretical analysis, and practical material coupling effects may limit its direct applicability.