j. stuart bolton ph.d. institute of sound and vibration research, southampton university, uk....

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 motion

xjktt

xeWW ~ xjkpp

xeWW ~

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)