Microstructure-based modeling to characterize low pore density open-cell foams and its experimental validation

Area of Science:

• Acoustics
• Materials Science
• Porous Materials

Background:

• Microlattices with large pores are vital for many applications, necessitating an understanding of their acoustic properties.
• Classical homogenization and equivalent fluid models fail for low pore density microlattice foams.
• Accurate acoustic prediction is essential for optimizing the performance of these materials.

Purpose of the Study:

• To propose and validate a microstructure-based direct fluid model (DFM) for predicting acoustic performance.
• To evaluate the DFM's accuracy for low pore density periodic open-cell foams with spherical pores.
• To compare DFM predictions with experimental data and traditional methods.

Main Methods:

• Developed a direct fluid model (DFM) incorporating microscale geometric features.
• Simulated the DFM for three-dimensional (3D) body-centered-cubic (BCC) porous foams (1-12 PPI).
• Conducted comparative studies using equivalent fluid models and experimental data over 500-4100 Hz.

Main Results:

• Homogenization methods showed significant deviation from experiments for PPI < 5.
• DFM predictions closely matched experimental results for 3D-printed samples across a range of PPI.
• Observed a transition from dissipative to reactive acoustic regimes as PPI decreased.

Conclusions:

• The direct fluid model (DFM) is a valid and accurate method for predicting the acoustics of low PPI microlattices.
• DFM provides superior accuracy compared to traditional homogenization methods for these materials.
• The study highlights the DFM's capability in capturing acoustic transitions in porous structures.