Acoustic fatigue analysis for perforated honeycomb sandwich structure based on vibro-acoustic coupling

Abstract:

To analyze the influence of different opening diameters in the upper panel of the honeycomb sandwich structure on its acoustic fatigue life, the vibro-acoustic coupling analysis was adopted in this study. First, the finite element analysis of the structure was performed to obtain low-order modes and corresponding frequencies. Next, the sound field was divided by boundary element, and a dynamic model of acoustic-structure coupling was built. In order to reduce calculation, principal component analysis was performed on the input noise load, the principal components of each order were extracted as input conditions, and the dynamic responses at each frequency and each principal component were obtained by numerical analysis. Then, the power spectral density (PSD) function of structural dangerous points was obtained by post-processing based on modal superposition. Lastly, the PSD method which combines P-M linear cumulative damage theory and probability density function was used to calculate the acoustic fatigue life of the structure. Result shows that although the structural panel opening caused the reduction of structural rigidity and the stress concentration of the hole edge, when the diameter of the opening was small, each honeycomb cell was a Helmholtz resonator. Consequently, the acoustic wave was affected by the viscosity when it propagated in the opening structure, and heat loss occurred during the propagation, which could absorb part of the acoustic energy and reduce noise. Therefore, the small open-cell structure has a positive effect on the acoustic fatigue life.