Numerical Study on the Acoustic Transmission Performance of New Hierarchical Honeycomb Sandwich Panel.

A novel hierarchical honeycomb structure is proposed as the core layer of sandwich panels, replacing the hexagonal vertices with other shapes. Its vibration and sound insulation performance are further discussed. Structural acoustic finite element analysis methods were used to simulate the natural frequency, sound transmission loss (STL), and sound pressure distribution within the acoustic domain of the sandwich panels. Within the given simulation parameter range, the sound insulation efficiency of the new hierarchical honeycomb sandwich panel was significantly improved, and the triangular vertex configuration exhibited the best noise reduction ability. By varying the vertex size and the dimensions of the units, the sandwich panels' vibration reduction and noise insulation capabilities can be further optimized. The average sound transmission loss (STLo) for hierarchical parameter (the ratio of the vertex edge length to the wall length) λ = 0.4 increases by 17.2% compared to λ = 0.2, greatly improving sound reduction efficiency. When the size of the honeycomb unit is small, the sandwich panel exhibits enhanced acoustic transmission loss within the resonance frequency range. The hierarchical honeycombs after vertex triangle rotation show an STLo level of around 43.08-44.24 dB. The influence of vertex triangle rotation on the STLo of hierarchical honeycomb is closely related to the hierarchical parameters, with STLo increasing by 14.8% for λ = 0.2 and 4% for λ = 0.3, while the opposite phenomenon occurs when λ is 0.4. The research results provide valuable insights into improving the vibration reduction and sound insulation performance of honeycomb sandwich panels within the target frequency range by introducing hierarchical features. However, related engineering applications need to rely on subsequent experimental verification.