Complex fluid properties of additively manufactured periodic lattice structures
* Presenting author
Abstract:
The volume of the cavity significantly influences the resonant frequency of resonators. The lower the frequency to be damped, the larger the required volume. The combination of resonators and passive porous absorbing material is intended to reduce the volume of the cavity and thus the required installation space. In order to design such a combined resonator and to adapt it to a target spectrum it is necessary to be able to manipulate the sound propagation in the porous medium. For this purpose, fine mesh additively manufactured periodic lattice structures are investigated in this work. These lattice structures are modelled with the surrounding air as complex fluids and the effective fluid properties are determined for different lattice constants as a function of frequency. With the determined complex fluid properties and the Johnson-Champoux-Allard-Lafarge (JCAL) model, it is now possible to calculate the complex fluid properties as a function of the lattice constant and the frequency. The fluid properties calculated using the JCAL model agree in good approximation with comparative measurements. Being able to predict sound propagation as a function of lattice constant and frequency using the JCAL model is an important step in the development of the combined resonator.