Optimized design and experimental validation of sound absorption coefficient performance in aluminium metal foam by...

Determining the structural properties of aluminum metal foam is essential to predicting its acoustic behavior. Acoustic models are presented that show the relationship between the morphology of the absorber and the sound absorption coefficient (SAC). Optimizing the parameters affecting the SAC can be the maximum theoretically SAC achieved at each frequency. In the previous article (https://doi.org/10.32604/sv.2021.09729) the parameters of porosity percentage (Ω), pore size (D) and pore opening size (d) were optimized by the genetic algorithm and Lu model. In this study, the optimal aluminum metal foam was synthesized using Spark Plasma Sintering (SPS), with the maximum temperature of 420 °C and final pressure of 20 MPa in samples with thicknesses of 5, 10, 15 and 20 mm in different frequencies from 1000 to 6300 Hz. The crystal structure and microstructure of samples were investigated using XRD and SEM. Optimized metal foam SAC (0.67, 0.9, 1 and 1) and experimental peak SAC (0.44, 0.67, 0.76 and 0.82) were compared with the optimized SAC in 5, 10, 15 and 20 mm thicknesses, respectively. The values of the coefficient of determination (R²) according to multiple linear regression (MLR) for the two optimized SAC and experimental in thicknesses of 5, 10, 15 and 20 mm were 0.90, 0.95, 0.96 and 0.90, respectively. The results of this study show that porous metal foam can have a high absorption coefficient in any desired thickness and frequency by using the optimal morphology.