Document Type
Dissertation
Date of Award
Fall 1-31-2003
Degree Name
Doctor of Philosophy in Mechanical Engineering - (Ph.D.)
Department
Mechanical Engineering
First Advisor
N. Aubry
Second Advisor
Pushpendra Singh
Third Advisor
E. S. Geskin
Fourth Advisor
Chul Lee
Fifth Advisor
Nanying Jia
Abstract
The sound transmission loss (STL) characteristics of polymer-based materials are considered. Analytical models that predict, characterize and optimize the STL of polymeric materials, with respect to physical parameters that affect performance, are developed for single layer panel configuration and adapted for layered panel construction with homogenous core. An optimum set of material parameters is selected and translated into practical applications for validation.
Sound attenuating thermoplastic materials designed to be used as barrier systems in the automotive and consumer industries have certain acoustical characteristics that vary in function of the stiffness and density of the selected material. The validity and applicability of existing theory is explored, and since STL is influenced by factors such as the surface mass density of the panel's material, a method is modified to improve STL performance and optimize load-bearing attributes. An experimentally derived function is applied to the model for better correlation. In-phase and out-ofphase motion of top and bottom layers are considered. It was found that the layered construction of the coinjection type would exhibit fused planes at the interface and move in-phase. The model for the single layer case is adapted to the layered case where it would behave as a single panel.
Primary physical parameters that affect STL are identified and manipulated. Theoretical analysis is linked to the resin's matrix attribute. High STL material with representative characteristics is evaluated versus standard resins. It was found that high STL could be achieved by altering materials' matrix and by integrating design solution in the low frequency range.
A suggested numerical approach is described for STL evaluation of simple and complex geometries. In practice, validation on actual vehicle systems proved the adequacy of the acoustical characterization process.
Recommended Citation
Homsi, Emile N., "Acoustical characterization and parameter optimization of polymeric noise control materials" (2003). Dissertations. 559.
https://digitalcommons.njit.edu/dissertations/559
