Simple multi-sections unit-cell model for sound absorption characteristics of lotus-type porous metals

This paper presents a simple multisection unit-cell model (UCM) with which to investigate the sound absorption characteristics of lotus-type porous metals (LTPMs). This model is inspired by analyzing micrographs of the LTPMs and by considering the relationship between the average pore diameter and the porosity. The multisection UCM is used to establish the analytical relationships between the basic nonacoustic parameters (namely, flow resistivity, tortuosity, and porosity) and the sound absorption characteristics of the LTPMs. The analytical predictions are compared with existing experimental data and with analytical results from a uniform UCM. Good agreement is found between the multisections UCM and the existing experimental results. The comparative relationships of the sound absorption coefficients of the LTPMs and uniform and graded open-cell foam aluminum are plotted as well.