Sound insulation performance of honeycomb core aluminum sandwich panels with flexible epoxy-based foam infill

The most distinctive features of sound insulation structures are their flexibility and porosity. Therefore, the flexible epoxy matrix material was made cellular using a suitable foaming agent. In addition, hollow glass mi-crospheres (HGMs) were added to the epoxy matrix. Thus, the sound wave refraction was increased by obtaining cavities in the cell walls. Structures with different densities and voids were created by changing the ratios of the filling material and foaming agents used in the sandwich. An aluminum (Al) honeycomb was used to protect the insulation materials' structural integrity and ensure the homogeneous distribution of sound waves. The effect of density differences on sound insulation values was investigated. The mechanical properties of sandwich struc-tures were determined using compression and three-point bending tests. The distribution of the filler in the matrix was visualized using SEM. TGA, DSC, thermal conductivity, dielectric, and flammability tests were also performed to determine their thermal, electrical, and flammability properties. During the formation of cells in the flexible epoxy, the HGMs were positioned in the cell wall by internal gas pressure. Low-density structures performed better at low frequencies, while high-density structures at high frequencies.

Automated summary

The distinctive features of sound insulation structures are flexibility and porosity. A cellular flexible epoxy matrix material was created using a foaming agent, and hollow glass microspheres were added to increase sound wave refraction. Structures with different densities and voids were formed by adjusting the ratios of filling material and foaming agents. An aluminum honeycomb was used for protection and homogeneous distribution of sound waves. The effect of density differences on sound insulation values was analyzed, and the mechanical, thermal, electrical, and flammability properties of the sandwich structures were evaluated.