Full-Gradient Optimization of the Vibroacoustic Performance of (Non-)auxetic Sandwich Panels

This paper aims to optimize vibro-acoustic response of (non-) auxetic sandwich panels by use of topology optimization method. First, structural noise and vibration responses of the auxetic panel with the re-entrant hexagonal honeycomb core are studied. It is proved that the interactions between the structural vibrations and induced noise are more complex when expected for a low-frequency range, and the optimized noise reduction can be obtained by a proper combination of auxetic and non-auxetic properties within a single structure. Therefore, vibro-acoustic response of the sandwich panel with a re-entrant hexagonal honeycomb core by applying a full-gradient two-dimensional geometry optimization method is analyzed and optimized. It is shown that under various random loads, the sound power level can be reduced by about 20% at the cost of a slight increase (< 5%) of the total mass. Besides, the structural Eigen frequencies are shifted to lower values that are desirable for applications, e.g., in the aerospace industry. The obtained results ensure that the proposed optimization approach delivers extra noise reduction for auxetic sandwich panels as compared to the results available in the literature.