Date Available
12-10-2014
Year of Publication
2014
Document Type
Master's Thesis
Degree Name
Master of Science in Mechanical Engineering (MSME)
College
Engineering
Department/School/Program
Mechanical Engineering
Advisor
Dr. David W. Herrin
Abstract
Soft trim absorbing parts (i.e., headliners, backwalls, side panels, etc.) are normally comprised of different layers including films, adhesives, foams and fibers. Several approaches to determine the complex wavenumber and characteristic impedance for porous sound absorbing materials are surveyed and the advantages and disadvantages of each approach are discussed. It is concluded that the recently documented three-point method produces the smoothest results. It is also shown that measurement of the flow resistance and the use of empirical equations is sufficient for many common materials. Following this, the transfer impedance of covers, adhesives, and densified layers are measured using an impedance difference approach. The transfer matrix method was then used to predict the sound absorption of a multi-layered materal which included a perforated cover, fiber layers, and an adhesive. The predicted results agree well with measurement.
Recommended Citation
Li, Wanlu, "EXPERIMENTAL STUDIES ON THE DETERMINATION OF ACOUSTIC BULK MATERIAL PROPERTIES AND TRANSFER IMPEDANCE" (2014). Theses and Dissertations--Mechanical Engineering. 48.
https://uknowledge.uky.edu/me_etds/48
