j. stuart bolton
DESCRIPTION
J. Stuart Bolton. Ph.D. Institute of Sound and Vibration Research, Southampton University, UK. Poroelastic materials and applied signal processing Professor of Mechanical Engineering Wave propagation and sound radiation Sound Field visualization Poroelastic materials Noise Control - PowerPoint PPT PresentationTRANSCRIPT
J. Stuart Bolton• Ph.D. Institute of Sound and Vibration Research, Southampton University, UK.
– Poroelastic materials and applied signal processing
• Professor of Mechanical Engineering– Wave propagation and sound radiation– Sound Field visualization– Poroelastic materials– Noise Control
• Americas Editor (with Patricia Davis) of the Journal of Sound and Vibration
• Funding from: 3M, Sony, Cummins Engines, Boeing, Raytheon Aircraft . . .
Optimization of Acoustic TreatmentsOptimization of Acoustic Treatments3 foams , 2 air space, 3 panel3 foams , 2 air space, 3 panel
FOAM1
FOAM2
FOAM3
AIR1
AIR2
Panel 2 Panel 3Panel 1
Incidence 1
Tc Transmitted
Reflection Rc
Area I
Z=0 Z=L1
Z=L2
Z=L3
II
Z=L4
Z=L5
III IV V VI VII
Honeycomb panel
solve for
Area I inin jP 0
Area II
Area IV
zv inzin
654321 hhhhhh CCCCCC
trtr jP 0z
v trztr
Panel motionxjk
ttxeWW ~ xjk
ppxeWW ~
654321 pppppp CCCCCC
Area V
Area III 21 11 AA
Area VI
Area VII
654321 qqqqqq CCCCCC
21 22 AA
Apply b.c.’s at each interface
SEM – ThinsulateSEM – Thinsulate
B&K Four-mic TL tubeB&K Four-mic TL tube
[ Direct BEM ]
radiation field characteristicsbased on Acoustic Radiation Mode
(Acoustic Transfer Vector)
SPL & Sound Intensity on a hemisphere surrounding a tire
Sound Power Radiation Efficiency
Radiation Mode Contribution[ Structural Harmonic FEM ]structural wave propagation
based on surface normal velocities
Component Noise: e.g. Tire Radiation Component Noise: e.g. Tire Radiation Analysis ProcedureAnalysis Procedure
Frequency # of nodes
164 Hz 8 (n=4)
140 Hz 6 (n=3)
115 Hz 4 (n=2)
n 3
From Dispersion Curve
Acoustical Holography for Noise Source Identification: Acoustical Holography for Noise Source Identification:
e.g. rolling tire at 21 mph (128 Hz)e.g. rolling tire at 21 mph (128 Hz)