The Interactive Liner Impedance Analysis and Design (ILIAD) tool is a software package used to design the composite surface impedance of an acoustic liner using resonant channels. ILIAD’s graphical user interface allows the acoustic channel geometry to be drawn in the liner volume while the surface impedance and absorption coefficient calculations are updated in real time. A one-dimensional transmission line model serves as the basis for the impedance calculation and can be applied to many liner configurations. The software can be used to design arrays of resonators that can be packaged into complex geometries heretofore unsuitable for effective acoustic treatment.

This innovation targets the difficult task of generating aircraft liner designs that offer broadband sound absorption in spaces previously unused for liners due to the geometric complexities of the available space. Working liner design from a graphical standpoint allows the designer to visualize the spatial relationship between the liner channels and the design space. Realtime analysis provides instant feedback on changes to the liner geometry, allowing liners to be designed to meet a specific surface impedance target spectra.

This work was done by Brian Howerton and Michael Jones of Langley Research Center. For more information on this technology, contact Langley Research Center at This email address is being protected from spambots. You need JavaScript enabled to view it.. Refer to LAR-18217-1

NASA Tech Briefs Magazine

This article first appeared in the January, 2016 issue of NASA Tech Briefs Magazine.

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