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Sound transmission characteristics of sandwich panels with a truss lattice core Moosavi Mehr, Ehsan

Abstract

Sandwich panels are extensively used in constructional, naval and aerospace structures due to their high stiffness and strength-to-weight ratios. In contrast, sound transmission properties of sandwich panels are adversely influenced by their low effective mass. Phase velocity matching of structural waves propagating within the panel and the incident pressure waves from the surrounding fluid medium lead to coincidence effects (often within the audible range) resulting in reduced impedance and high sound transmission. Truss-like lattice cores with porous microarchitecture and \emph{reduced} inter panel connectivity relative to honeycomb cores promise the potential to satisfy the conflicting structural and vibroacoustic response requirements. This study combines Bloch-wave analysis and the Finite Element Method (FEM) to understand wave propagation and hence sound transmission in sandwich panels with a truss lattice core. Three dimensional coupled fluid-structure finite element simulations are conducted to compare the performance of a representative set of lattice core topologies. Potential advantages of sandwich structures with a lattice core over the traditional shear wall panel designs are identified. The significance of partial band gaps is evident in the sound transmission loss characteristics of the panels studied. This work demonstrates that, even without optimization, significant enhancements in STL performance can be achieved in truss lattice core sandwich panels compared to a traditional sandwich panel employing a honeycomb core under constant mass constraint.

Item Metadata

Title
Sound transmission characteristics of sandwich panels with a truss lattice core
Creator
Moosavi Mehr, Ehsan
Publisher
University of British Columbia
Date Issued
2016
Description
Sandwich panels are extensively used in constructional, naval and aerospace structures due to their high stiffness and strength-to-weight ratios. In contrast, sound transmission properties of sandwich panels are adversely influenced by their low effective mass. Phase velocity matching of structural waves propagating within the panel and the incident pressure waves from the surrounding fluid medium lead to coincidence effects (often within the audible range) resulting in reduced impedance and high sound transmission. Truss-like lattice cores with porous microarchitecture and \emph{reduced} inter panel connectivity relative to honeycomb cores promise the potential to satisfy the conflicting structural and vibroacoustic response requirements. This study combines Bloch-wave analysis and the Finite Element Method (FEM) to understand wave propagation and hence sound transmission in sandwich panels with a truss lattice core. Three dimensional coupled fluid-structure finite element simulations are conducted to compare the performance of a representative set of lattice core topologies. Potential advantages of sandwich structures with a lattice core over the traditional shear wall panel designs are identified. The significance of partial band gaps is evident in the sound transmission loss characteristics of the panels studied. This work demonstrates that, even without optimization, significant enhancements in STL performance can be achieved in truss lattice core sandwich panels compared to a traditional sandwich panel employing a honeycomb core under constant mass constraint.
Genre
Thesis/Dissertation
Type
Text
Language
eng
Date Available
2016-01-30
Provider
Vancouver : University of British Columbia Library
Rights
Attribution-NonCommercial 2.5 Canada
DOI
10.14288/1.0223865
URI
http://hdl.handle.net/2429/56785
Degree
Master of Applied Science - MASc
Program
Mechanical Engineering
Affiliation
Applied Science, Faculty of; Mechanical Engineering, Department of
Degree Grantor
University of British Columbia
Graduation Date
2016-02
Campus
UBCV
Scholarly Level
Graduate
Rights URI
http://creativecommons.org/licenses/by-nc/2.5/ca/
Aggregated Source Repository
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Attribution-NonCommercial 2.5 Canada