Eng Noise Control Figures

8/4/2019 Eng Noise Control Figures

1/189

The following are figures from Engineering Noise

Control by Bies and Hansen , 3rd edition. You can

enlarge parts of them by using the cropping tool and then

stretching with the mouse. The figures are not numbered

but they are in the same order that they are in the text

book.

Good luck!


2/189


3/189

(a)

(b)

+ +

wavelength

acoustic

pressure

patm

pmax


4/189

10

20

20

50 100 200 500 1000 2000 5000 10000 20000

audible frequency (Hz)

wavelength (m)

5 2 1 0.5 0.2 0.1 0.05 0.02


5/189

y t X t( ) = sin

xt

X

t

()=

cos

X

X

0

0

-X

-X

2

2

3 4

3

4

t

t

xt()

y t( )

X

x

y

Im

Re

t0


6/189

t

p2

p12

p1

Im

Re


7/189

20000

10000

5000

2000

1000

500

200

100

50

20

10

5

2

1

0.5

0.2

0.1

0.05

0.02

0.01

0.005

0.002

0.001

0.0005

0.0002

0.0001

0.00005

0.00002

0.00001

0.000005

-10

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180large military weapons

firearms

boom boxes inside cars

upper limit for unprotectedear for impulses

pneumatic chipper at 1.5 m

textile loom

newspaper press

diesel truck, 70 km/hr at 15 m

passenger car, 80km/hr at 15 m

conversation at 1 m

quiet room

median hearing threshold(1000 Hz)

threshold for those with very

good hearing

audiometric test room

whispered speech

teenage rock and roll band

power lawnmower at operator's ear

milling machine at 1.2 m

garbage disposal at 1 m

vacuum cleaner

air conditioning window unit at 1 m

A-weighted sound pressurelevel in dB re 20 Pa

Sound pressurein Pa

walkman (personal stereo)

snowy, rural area - no windno insects


8/189

(a)

(c)

(e)

(b)

(d)

(f)

p

p

p

t

t

t


9/189

p

p

p

t

t

t

f

ff1

f1 f2 f3

Frequency bands

(a)

(c)

(e)

(b)

(d)

(f)

p2

p2

p2


10/189

x

t


11/189


12/189

Oval WindowResonance

Helicotrema

Stapes

RoundWindow


13/189

outer hair cells

scala media(endolymph)

Hensen'sstripe

tectorial

membrane

innerhair cell

basilarmembrane tunnel

of Corticochlear

nerve

scala tympani(perilymph)

Reissner'smembrane

stria vascularis

rods ofCorti

spiralsulcus

reticularlaminahair cell

stereocilia

scala vestibuli(perilymph)

scala tympani(perilymph)

cochlear duct(endolymph)

scala vestibuli(perilymph)

(a)

(b)


14/189

70010001400200028004

6

8

10

12

14

16

18

ABasal End Apical End

Frequency (Hz)

TemporaryThresholdShift(dB)

B


15/189

1

2

3 a b (stimulus)

c (half octave above)

Cochlear Duct

CharacteristicFrequency(Hz)

Basal End Apical EndA B


16/189

200 300 500 1000 2000 5000 100000

0.1

0.2

0.3

0.4

0.5

Frequency (Hz)

ff


17/189

0.25

0.25

0.2

0.2

0.4

0.4

0.5

0.5

0.63

0.63

0.8

0.8

1

1

1.25

1.25

1.6

1.6

2

2

2.5

2.5

3.15

3.15

0

0

20

20

40

40

60

60

80dB

80dB

Thresho

ldshift(dB)

Thresho

ldshift(dB)

40 dB

40 dB

60 dB

60 dB

4

4

Frequency of masked tone (kHz)

Frequency of masked tone (kHz)


18/189

0.2 0.25 0.315 0.4 0.5 0.63 0.8 1 1.25 1.6 2 2.5 3.15

0

20

40

60

4Frequency of masked tone (kHz)

Threshold

shift(dB)

410 Hz narrow band of noise,80 dB masking level

400 Hz tone,80 dB masking level


19/189

120

100

100

80

80

60

60

40

40

20

20

MAF

MAF

0

0

20

20

40

40

60

60

80

80

100

100

120

120

31.5

31.5

63

63

125

125

250

250

500

500

1k

1k

2k

2k

4k

4k

8k

8k

Octave band centre frequency (Hz)

Tonal frequency (Hz)

Soundpressurelevel(dBre20

Pa)

Soundpressurelevel(dBre20

Pa)

140

140

(a)

(b)


20/189

Band pressure leveldB re 20 Pa 110

100

90

80

70

60

50

40

30

20

0.1

1

10

100110

100

90

80

70

60

50

40

30

20

31.5 63 125 250 500 1k 2k 4k 8k

One-third octave band centre frequency (Hz)

LoudnessLevel,

(Phons)

P

Loudnessind

ex,

(sones)

S

10

20

30

40

50

60

70

80

90

100

110

120

130

31.5 63 125 500 1k 2k 4k 8k 16k250

Bandsoundpressure

level(dB

)

re20

Pa

150

100806050403025201512

1086543

2.521.5

1.0

0.70.50.30.20.1

One-third octave band centre frequency (Hz)

Loudness index(sones)S

(a)

(b)


21/189

10000

1000

100

A(linear)

B(low SPL)

31.5 63 125 250 500 1000 2000 4000 8000

Frequency (Hz)

Subjectivepitch(mels)

increasingSPL

increasingSPL


22/189

(a) (b)

grid

vent

diaphragm

conductor insulator

electrode

E

E0

CCS

RpR


23/189

(a) (b)

grid

vent

diaphragm

conductor insulator

piezo-electricmaterial

E

E

C

CsR

s

0

R


24/189

DFR

0

30

60

90

120

180

o

o

o

o

o

o

0.16 0.25 0.4 0.63 1.0 1.6-10

0

10

Sensitivity(dB)

d/


25/189

-30

-40

-50

0.01 0.1 1.0 10 100

frequency (kHz)

Sensitivity

(dBre1V

Pa)

A

B

C


26/189

0

-5

-10

-15

-20

-25

-30

-35

-40

-45

-50

31.5 63 125 250 500 1k 2k 4k 8k 16k

One-third octave band center frequency (Hz)

Levelweighting(dB)

A

B

C


27/189

1 2 3

4

5

6

7


28/189

50.0mm

28.9mm

40.8mm

120

6.1mm

1

2

34

1,2

3

4

4

1

2

3


29/189

Average 4

1234

Average 4

6860

6860

6860

Pressure

Velocity 1

Velocity 2

Velocity 3

rms

rms meter

rms1234

2nd orderButterworthHP filter 2




4 4

3 3

Mic 4

Mic 3

Mic 2

Mic 1

1

1

2 21s

1s

1s

Diff

Diff

Diff

Integrator

Integrator

Integrator

Gain

Gain

Gain

5

Av


30/189

10 dB

t1 t2Time (sec)

Soundpressurelevel(dB

)

Maximum sound level

LAE - Shaded areaunder curve


31/189

31.5 63 125 250 500 1000 2000 4000 8000 16000

Octave band centre frequency

Hearingthreshold(dB)

0

20

40

60

80

100

Age(years)

M

M

M

W

W

W40

20

80

60Speech range


32/189

31.5 63 125 250 500 1000 2000 4000 8000 16000

0

20

40

60

80

Hearingth

reshold(dB)

Octave band centre frequency

Speech range

Years ofexposure

35-3925-29

15-195-91-2

Exposure


33/189

Inadequate for speech recognition

Inadequate for speech recognition

Adequate for speech recognition

Adequate for speech recognition

Exposure(years)

10203040

10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

Percentage risk of developing a hearing handicap

Medianloss(dB)

(a)

80 dB(A)

90 dB(A)

100 dB(A)110 dB(A)

10 20 30 40 50 60 70 80 90 1000

10

20

30

40

50

60

70

Percentage risk of developing a hearing handicap

Medianloss(dB)

(b)

HDI

50

55

60

65

70HDI dt

L

t

10 101020

0

log /


34/189

F

B

A

C

B

EDA

20 dB

(a)

(b)


35/189

impact and steady state (equal energy)

5 dB / doublingsteady state

impulse180

170

160

150

140

130

120

110

100

90

0.1 1 10 10 10 10 10 10 10 10 102 3 4 5 6 7 8 92 5 5 5 5 5 5 5 5

8-hour dB(A)

equivalent

B-duration x number of impulses (ms)

Peaksoundpressure

level(dBre20

Pa)


36/189

A-Weighted level (dB(A))

40 50 60 70 80 90 100

30 40 50 60 70 80 900.25

0.5

1

2

4

8

16

Speech interference level (dB 20 Pa)re

Dis

tanceinmetres

Norm

al

Veryloud

Shout

Ampli

fiedvoicelimit

Rais

ed

ExpectedVoiceLevel

100


37/189


38/189

0

10

20

30

40

50

60

70

80

65

55

45

35

15MAF

63 125 250 500 1k 2k 4k 8k

Octave band center frequency (Hz)

Octavebandsoundpres

surelevel(dBre20

Pa)

(NC)

25


39/189

45

35

25

30

40

50

(RC)

16 31.5 63 125 250 500 1k 2k 4k 8k

10

20

30

40

50

60

70

80

90

Octavebandsoundpre

ssurelevel(dBre20

Pa)


A

B


40/189

45

35

25

30

40

50

(RC)

16 31.5 63 125 250 500 1k 2k 4k 8k

10

20

30

40

50

60

70

80

90

Octavebandsoundpre

ssurelevel(dBre20

Pa)


A

B


41/189

0

10

20

30

40

50

60

70

90

80

100

65

55

45

35

15

10

0

6316 12531.5 250 500 1k 2k 4k 8k


Octavebandsoundpressurelevel(dBre20mPa) (NCB)

25

A

B

90


42/189

(RNC)

16 31.5 63 125 250 500 1k 2k 4k 8k

10

0

20

30

40

50

60

70

80

90

Octavebandsoun

dpressurelevel(dBre20

Pa)


50

45

35

20

25

10

30

15

40


43/189

longitudinalwave front

source


44/189

h

-h

x

H

O

source 1

source 2

r

r1

r2

y


45/189

+


46/189

h

L

-L

-h

x

O

r

r1

y

z

+

+


47/189

D

b

dr0

x

u O

rn


48/189

z

r

a

y

x

O

d d

r


49/189

0

0.5

1.0

1.0 2.0 3.0 5.0 7.0 8.0 9.0 10.0

Fw

U

a

()

/

2

w


50/189

dS

dS

rd

dr

dy

d

h

ar


51/189


52/189

H

d

r

yx

z

L

ri

h

O

0Planes

ource

0


53/189

referencepointsource

=1.0

=0.1

=0.5=0.2

-10

-20

-30

-40

0.1 1.0 10

Relativeattenuation(dB)

r / HL


54/189

source S

observer O

SI a

b


55/189

Z k1 1

Z k2 2

y

x

rR

rI

rT

incident wave reflected wave

transmittedwave

medium 1

medium 2


56/189

hs

hr

r

r1r2

L

air

ground

source

receiver

imagesource

125,2

50

0


57/189

10

100

1000

30 40 50 60 70 80 90K1 Attenuation (dB)

63,

500

1k

2k

4k

8k

Distancefromso

urce(m)

(a)

1.0

2.0

5.0

10

0 10 20 30

K1 Attenuation (dB)

Distancefromso

urce(m)

(b)


58/189

250, 500

1k, 2k

125, 4k

8k

0 200 400 600 800 10000

5

10

15

K2

-additionalattenuation

Distance from source (m)


59/189

r1r2


60/189

-5

0

5

10

15

100 1000 2000


Attenuation(dB)

500

250

500

125

1000

4000

2000

63


61/189

1 10 100 1000 10,000

10

20

0

Reflection parameter, [ / ] (degrees) R f11/2

Reflection

loss

(dB)

AR

less than 0.001

0.01

0.02

0.05

0.1

0.2

f R/ =11

Sound Receiver


62/189

Soundsource

Soundsource

u

- C

C

r1

Shadowzone

xReceiver

Receiveron shadow

border Receiverwell intoshadow

Soundray

r1

rx

hrhs

ground


63/189

Excessattenuation(dB)

Distance from sound source ( / )r x

0

10

20

30

0.5 1 2 4 8

65 =75 =80

=90


64/189

-20 0 20 40 60 80 100 120 140 1600

10

20

30

( ) degrees C -

Limitingvalueof

excessat

tenuation(dB)


65/189

-15

-10

-5

0

5

10

15

100 500

CAT 1

CAT 2CAT 3

CAT 5CAT 6

1000 2000


Attenu

ation(dB)

(a)

15


66/189

-15

-10

-5

0

5

10

100 500

CAT 1

CAT 2

CAT 3

CAT 5

CAT 6

1000 2000


Attenuation(dB)

(c)

-15

-10

-5

0

5

10

15

100 500

CAT 1

CAT 2

CAT 3

CAT 5CAT 6

1000 2000


Attenua

tion(dB)

(d)

-15

-10

-5

0

5

10

15

100 500

CAT 1

CAT 2

CAT 3

CAT 5

CAT 6

1000 2000


Attenuation(dB)

(e)

15


67/189

-15

-10

-5

0

5

10

100 500

CAT 1CAT 2

CAT 3

CAT 5

CAT 6

1000 2000

Attenuation(dB)

(f)

-15

-10

-5

0

5

10

15

100 500

CAT 1CAT 2

CAT 3

CAT 5

CAT 6

1000 2000


Attenuation(dB)

(g)

30


68/189

= /

=2

/r

0.1 0.2 0.3 0.5 1 2 3

3

5

5

10

10

20

20

30

30

0.3

0.5

1

2

Far field

Geometricnear field

Hydrodynamicnear field

Transition

Transitio

n

Transition

=1/

=1

/


69/189

z=0

0.36

0.36

0.93

0.93

0.58

0.58

14

8

910

5 2

36

12 11

x

y

7


70/189

0.5

1

22.5

3

44

8

7 6

0.01 0.1 10

2

4

6

8

10

Correctionfactor,

,(dB

)

1

Area ratio, 1 / 2S S

Lp Lp1 - 2 (dB)

1.5


71/189

10

0

-10

-20

-30

10Log

0.01 0.1 1.0 10

Frequency ratio, /f fc

Ph/A

0.1

0.05

0.012

0.006

0.003


72/189

tiny source ofsound at x = y = z = 0

x

z y

Lx

Lz

Ly

90 (a)


73/189

80 100 125 160 200 250 315

60

70

80

90

Frequency (Hz)

20 25 31.5 40 50 63 80

50

60

70

80

90

010

100

001

110

011

101

020

111

120

200

210

121

201

002

030

Lp(

dBre20

Pa)

(a)

(b)


74/189

3 dB

Frequency (Hz)

Room-respon

se,

(dB)

Lp

measurement band

bandwidth

z


75/189

sphericalregion

2r

I

y

x

dS (circularsection area)


76/189

loudspeaker

reverberant enclosure

microphone

noisegenerator

bandpassfilter

poweramplifier

graphiclevelrecorder

bandpassfilter

sound levelmeter

1.0


77/189

R c1/ = 3

45

1020

50

100

2005001000

10000100000

10-3

10-2

10-1

100

101

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

f /c

st


78/189

1.0

0.8

0

0.2

0.4

0.6

0.01 0.02 0.04 0.063 0.1 0.2 0.4 0.63 1.0

f /c

10% open area

>25% open area

panel absorber0% open area


79/189

A

B

C

D

E

F

G

H

IJ

0.15 0.2 0.5 1.0 2 4 6 8 100.0

0.2

0.4

0.6

0.8

1.0

1.2

f f/0

10.0


80/189

400

3

50

300

250

200

175

150

125

100

85

70

60

50

40

A

B

C

D

E

F

G

H

I

J

0.3

0.5

1.0

2.0

3.0

5.0

25 30 50 100 200 500 1000 1500

Cavity depth, (mm)L

Surfaceden

sity,

(kgm-2)

m

f0 (Hz)

10


81/189

0.1 1 10 100

0

-10

-20

-30

r a/

=0.9

0.7

0.5

0.3

0.1

10log

()

-10log

(

/

)

10

2

10

2

pr

W

ca

10


82/189

0.1 1 10 100

0

-10

-20

-30

r/a

=0.9

0.70.5

0.3

0.1

10log

()

-10log

(

/

)

10

2

10

2

pr

W

c

a

20


83/189

-10

0

10

10log

(

)-

1

0log

(

/2)

(dB)

10

10

ph

pa

2

2

0 0.5 1

h/a

1= 0.9

2

= 0.1

r= 0

r a>>

r a=

10


84/189

0.1 1 10 100

0

-10

-20

-30

r/a

(a)

(b)

10log

()

-10log

(

/

)

10

2

10

2

pr

W

ca

10


85/189

0.1 1 10 100

0

-10

-20

-30

r/a

= 0.9

0.7

0.5

0.3

0.1

10log

()

-10log

(

/

)

10

2

10

2

pr

W

c

a

10


86/189

0.1 1 10 100

0

-10

-20

-30

r/a

=0.9

0.7

0.5

0.3

0.1

10log

(

)

-10log

(

/

)

10

2

10

p

r

W'ca

10


87/189

0.1 1 10 100

0

-10

-20

-30

r/a

= 0.9

0.7

0.5

0.3

0.1

10log

()-

10log

(

/

)

10

2

10

2

pr

W

ca

10


88/189

0.1 1 10 100

0

-10

-20

-30

r/a

= 0.9

0.7

0.5

0.3

0.1

10log

()

-10log

(

/)

10

2

10

pr

W'ca


89/189

h2

h1 material 1

material 2

neutralaxis

y

(a)


90/189

(a)

(b)


91/189

neutralaxis

z1

h

b3

b4b2

z2z3

z4

b1

4 2

2 4


92/189

5

10

15

20

25

125 250 500 1k 2k 4k

1/3 octave band centre frequency

TL(dB)

STC 16


93/189

45 65

40 70

50 60

55 55

60 50

65 45

125 250 500 1k 2k 4k

1/3 octave band centre frequency

L

n(dB)

IIC 50

ImpactInsulationClass(IIC)

ve(a) Isotropic


94/189

Frequency (Hz)

Transmissionloss(dB)

stiffnesscontrolled

mass law

frequency of firstpanel resonance

coincidenceregion

dampingcontrolled

6d e

octv

a e

B rp

9

tav

dB

pero

ce

coincidenceregion

stiffnesscontrolled

first panelresonance

dampingcontrolled

masslaw

9dB

t

ocave

per

Frequency (Hz)

Transmission

loss(dB)

(b) orthotropic


95/189

Y

X

Z

P

(a)


96/189

6dB

pero

ctave

9dB

per octave

A

B

TL(dB)

0.5 1.0

f fc/ (log scale)

0.5fc c 0.5f 2fc c2 21 1f

A

B

CD

6dB

per

octav

e

6dB

per

octav

e

(log scale)f

TL(d

B)

(b)


97/189

Frequency (Hz) (log scale)

TL(dB)

6dB/oct.

12dB

/oct.

18

dB

/oct.

6dB/oct.

15dB/

oct.

A

D BC

f0 f 0.5fc2 fc2

70

Bct.


98/189

One-third octave band centre frequencies (Hz)

Transmissionloss(dB)

63 125 250 500 1000 2000 4000 800010

20

30

40

50

60

A

B

C

6dB

/oct.

18

dB/o

ct.

6dB/

oct.

15

dB

/oc

measured

calculated (Sharp)

calculated (Davy)

50


99/189

8

45

40

35

30

25

20

15

10

5

0

5

10

15

20

25

30

35

40

45

10 10 10 10 10-5 -4 -3 -2 -1

1 10 100

5 5 5 5 52 2 2 2 2

Area ratio, /S S1 2

TL(dB)

TL =

TL > TL

TL = TL - TL

TL=TL + TL

2 1

2 1

1


100/189

gap=50mm

20mm10mm

5mm

100 200 300 500 1000 2000 3000 5000Frequency (Hz)

0.05

0.1

0.2

0.3

0.5

1.0

Transmissio

ncoefficient,

10

7

5

3

1

TL(dB)

30


101/189

TL = 30

20

10

5

1

2

3

4

6

8

10

20

0.4 0.5 0.63 0.8 1.0

Ratio of covered to total area

Soundpo

werreduction(dB)


102/189

source at( )X Y ZS S S, ,

receiver at

( )X Y ZR R R, ,

ZR

Y

XS XR

B

barrier ofheight h

YS

YR

d

hb

A

X

practical


103/189

0

5

10

15

20

25

-0.3 0

-0.01-0.1

-0.05

0.01 0.1

0.05 0.2 0.6 1.0

0.4 0.8

2 4 6 8 10 20 40 60 100

Attenuation,

(dB)

b

Fresnel number, N

practicalupper limit

incoherentline source

point or coherentline source


104/189

O

S S

S SR

R R

A B

(a) (b)

bar i


105/189

OO

O

R

S

S

ground

ground

barrier


106/189

90

90

120

120

150

150

180

180

(degrees)

(degrees)

34

K = 5

7

8

9.4

9.8

2

6

9

receiver

source


107/189

A C B

d

d

AB

N0

Source

Source

Receiver

Receiver

wind


108/189

effective

source position

windcurved sound

ray trace

top of barrier

Hb

S

'S

R

A

h'S

source


109/189

source at( )X Y ZS S S, ,

receiver at( )X Y ZR R R, ,

Z = hR r

Y

XS

X

XR

B

double edgebarrier ofheight h

YS

YR

d

hb

A e

b

b

a

50


110/189


63 125 250 500 1000 2000 4000 8000

0

10

20

30

40

Octaveba

ndinsertionlos

s


111/189


112/189

7

throat equally spacedtotal area

throat area

holes of

equal to


113/189

w


114/189

areaA

Z p va = / 0

0 x

x = -


115/189

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1 2 3 4 5 6 7 8 10 20 30 50 70 100

n

K


116/189

area A

Z p va = /

xx = -

0

volume V(a)


117/189

area , lengthA

sound

Zu

Zs ZdP v, v1

v2

(b)


118/189

1 2 3 4 5 6 7

8

9 10 11 12

13

14 15 16 17 18 1920

2122

2324 25

26

2728

29

30

3132

33 3435

3637

38

39 4041

4243

4445

4647

4849

50

51 5253 54

55

56

57

58

resonator splitter airway

throat length

135 degrees

throatwidth

Helmholtzresonator

(a)

(b)

(c)

flow

x y(a)


119/189

v, p v1 v2

Za

Zb Z +Zc L

a c

b

B

sound

source

(load, )L

(b)

11 cm

microphoneloudspeaker

v


120/189

30 40 50 70 100 200 300 500

-20

-10

0

10

20

U= 70 ms-1

U= 30 ms-1

U= 0

Frequency (Hz)

Insertionloss,

(dB)

IL

50 cm 20 cm 35 cm

v

(a)


121/189

Za

ZLv, p ZdZb

Zc

vb vd vL

source ( )load,Lca eb d

(b)

UD

r

U d2d1

(a) (d)


122/189

H

W

U U U

D

r

U

U

d1 d2U d1 d2U

L

U (degrees)

(b) (e)

(c) (f)

(g)

(h)

unsteady shear forces at reattachment(longitudinal quadruple source)


123/189

U

H

unsteady point of reattachment(drag dipole source)

B C

D


124/189

AD

E

d u c t

i n n e rw a l l


125/189

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0.0

0.5

1.01.5

2.0

2.5

3.0

3.5

0.01 0.1 1 100.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

.01 0.1 1 10

Attenuationrate(dBper

ductlength)

h

2h

curveno

h

12

345

0.250.5

124

Rc1

R

c1

Rc1

Rc1

R

c1

Rc1

= 1 = 2

= 8

= 12 = 16

= 4

123 123

12345 12345

2345

1 1

2345

2h/


126/189

0.0

0.0

0.5

0.5

1.0

1.0

1.5

1.5

2.0

2.0

2.5

2.5

3.0

3.0

0.01 0.1 1 100.0

0.5

1.0

1.5

2.0

2.5

3.0

.01 0.1 1 10

Attenuationrate

(dBper

ductlength)

h

2h

curveno

h

12

345

0.250.5

124

Rc1

= 1R

c1

= 2

Rc1

= 8

Rc1

= 12R

c1

= 16

Rc1

= 4

1 1234

1234512345

1234

5

1234

5

2h/


127/189

0.0

0.0

0.5

0.5

1.0

1.0

1.5

1.5

2.0

2.0

2.5

2.5

3.0

3.0

3.5

3.5

4.0

4.0

0.01 0.1 1 100.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

.01 0.1 1 10

Attenuationrate

(dBper

ductlength)

h

2h

curveno

h

12

345

0.250.5

124

Rc1

= 1R

c1

= 2

Rc1

= 8

Rc1

= 12R

c1

= 16

Rc1

= 4

12

123

1234512345

12345

1

2345

2h/


128/189

0.0

0.51.0

1.5

2.0

2.53.0

3.5

4.0

4.5

5.0

5.5

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0.01 0.1 1 100.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

.01 0.1 1 10

2h/

Attenuationrate

(dBper

ductlength)

h

2h

curveno

h

123

45

0.250.51

24

Rc1

= 8

Rc1

= 12R

c1

= 16

Rc1

= 4

Rc1

= 1R

c1

= 2

12345 12345

12345 12345

1

2345

1

2345

2.5

3.0

R1= 1

Rc1

= 4curveno

h


129/189

0.01 0.1 1 100.0

0.5

1.0

1.5

2.0

2.5

.01 0.1 1 10

0.01 0.1 1 100.0

0.5

1.0

1.5

2.0

2.5

3.0

c = 1

Rc1

= 12

cno

12

34

0.010.1

12

hh

h

h

= 1.0

= 2.0

= 0.25

M= 0

M= 0

M= 0

124

3

12

4 3

124 3

2h

2

2

h

h

/

/

Attenuationrate(dBper

ductlength)

h


130/189


131/189

0.1 0.2 0.4 1.0 2 40

5

10

15

Inletc

orrection(dB)

Dimensionless frequency, A/

30

Expansion ratio = 9m


132/189

0 2 4 6 8 10 12 14 16 18 200

5

10

15

20

25

Total attentuation of lining (dB)

Transmissionlossoroverallattenuation(

dB)

6

4

3

2

m = 9

p

6

43

2

1


133/189

0.1 0.2 0.4 1.0 2 40

5

10

15

20

Ductbendcorrection(dB)

S Dimensionless frequency,

A

B

C

D

E

F


134/189

out

in

H

L

area A

area A

(a) (b)


135/189

no water

with water

31.5 63 125 250 500 1000 2000 4000 8000 16,00060

70

80

90

100

110


OctavebandSPL(dBre

20Pa)

60

780W t lit d


136/189

31.5 63 125 250 500 1000 2000 40000

10

20

30

40

50


Octavebands

oundattenuation

(dB)

780

500

300

150

30

12

Water, litres per second =

10 0o


137/189

-10

-20

0

10

Direct

ivityIndex(dB)

0.2 1 10 202

fd/c

=0

30o

45o

60o

90o>120o


138/189

m F t F t ( ) = sin0


139/189

Ck

m

C

U t U t ( ) = sin0

k

10


140/189

= 1.00.7

0.5

0.3

0.20.1

0.0

0.1 1 100

0.1

1

Frequency ratio,f f/ 0

Forcetransmissibility,

T

Percent forcetransmissibility

2,000 0.2

n


141/189

Disturbing frequency (cycles per minute)

Staticd

eflection(mm)

Naturalfreque

ncy(cyclesperminute)

607080

90100

200

300

400

500

600700800900

1,000

100 200 300400500

600700

800900

1000 2000 3000

100

10

1

Amplific

ation

tobe

avo

ided

Non-

criti

calapp

licatio

ns

applica

tions

Extre

mel

ycritic

alC

ritical

applica

tions

Reso

nance

100%

30%

20%

10%

5%3%

2

%

1%

Shock-a

bsor

ptio

n

applica

tions


142/189

x

y

y

z2h

2b

2e

c . g . xx

mass m

a

b b

(a) (b)

(a) (b)


143/189

M

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

0.

2

0.3

= 1.0 = 1.0

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0

3.5

3.02.82.62.42.22.01.81

.61.

41.21.1

1.05

W

(a) (b)=0.4

0.45

0.5

0.6

0.7

0.8

0.9

=

4.0


144/189

C2

C1

mass m2

k2

mass m1

k1

y2

y1

Fej t

1.0


145/189

Resultantnaturalfreque

ncy

Naturalfrequencyas

o

kf

o

Stiffness of isolatorStiffness of frame

kikf

,

0 0.5 1.0

0.7

0.8

0.9

air

1250


146/189

Deflec

tion(mm)

Naturalfrequency(Hz)

springs

metalsprings

rubber andelastomers

cork and feltpads

100

31

10

3

0.025

0.25

2.5

25

0.7

0.8


147/189

Unstable

Stable

(Hinged ends)

(clamped ends)

Relativecompression,

0 0/D

0

0.1

0.2

0.3

0.4

0.5

0.6

1 2 3 4 5 6 7 8 9 10

0 2 4 6 8 10 12 14 16 18 20


148/189

Naturalfrequency(Hz)

10 20 40 100 200 400 1,000

20

30

40

Static load (kPa)

Hard

Medium

Soft

mass y2


149/189

C2

C1

massm2

k2

mass m1

k1

y2

y1

Fej t


150/189

visco-elastic material

metal layer

base structure


151/189

0

-3

-7

frequency (Hz)f0

20lo

g

vvmax f

2f

discharge discharge


152/189

intake

(a) Centrifugal fan,blow-through type

intake

(b) axial flow

discharge

intake

(c) Induced draftpropeller-type

discharge

intake

(d) Forced draft, propellor-typeunderflow

0


153/189

L

L

p

p

(dB

reoverall

)

f f/p

1----

32

1----

16

1----

8

1----

4

1----

2

1 2 4 8 16 32 64

-40

-30

-20

-10

0

acousticallyabsorptive lining

aspiratedair

t b l t t b l t


154/189

turbulent

mixing region

coreorifice

(a) Absorptive lined shroudsilencer

orifice

(b) Multiple-jet diffuser-typesilencer

turbulentmixingregion

diffused air

orifice

porous material

(c) Diffuser-type silencer

orifice mixingregion

core

entrained air

air shroud

gas flow

(d) Cross-section of air shroudsilencer

M ddj

valve orifice

PP


155/189

staticpressure

distance through valve

Mj didj

P1 = inlet pressure

P P F P2 1> - (0.472 )L 1

P P =P F P2 1 1= - (0.472 )2C L

P P = P2 1= 0.5280C

P P = P2 1= 0.072CE

P P2 2 1=P B


156/189

segment length near sideof track


157/189

R

line bisectingangle of view

DUCT ErrorPrimarynoise


158/189

FIRFilter

Weight UpdateAlgorithm

Controlsource

Errormicrophone

SignalConditioning

Error pathdelay estimate

Physicalsystem

Controller

Fan shaft

Tachometer

noise


159/189

wN-1

in

out

z -1z -1z -1

w0

w1


160/189

FIRFilter


DUCT

Controlsource

Error

microphoneReferencemicrophone


Physicalsystem

Controller

DUCT


161/189

FIRFilter

FIRFilter


DUCT

Controlsource

Errormicrophone

Referencemicrophone


Physicalsystem

Controller

H

IIRFilter


162/189

-90

-80

-70

-60

-50

-40

Noisereduction(dB)

0 100 200

Frequency (Hz)

Uncontrolled

Controlled


163/189

DUCT

Controlsource

ErrormicrophonePrimary noise

Amplifier

CompensatingFilter

44


164/189

8

6

4

10

14

12

16

8

66

8

6

48

12

1012

18

14

ElectronicControlSystem

PhysicalControlSystem Primary


165/189

Controller

System System PrimaryDisturbance

ControlSources

ErrorSensors

Enclosure

ReferenceSensor

PrimaryDisturbance


166/189

Phase

(degrees)

Amplitude

(dB)

102030

40

50

-135-90-45

04590

135

Mode1,1 1,3 3,1 3,3 1,5

Phase

(degrees)

Amplitude

(dB)

-135-90-45

04590

135

20

40

60

80

Mode0,0,1 0,2,0 0,0,2 0,2,1

Control ForceCancel Reinforce Cancel

ModalRearrangement

Structural Modes Acoustic Modes

40 dBAttenuation

primary controlled

moden=3

moden=1

P

m

s(n)

p(n)

++

noise in noise out


167/189

Adaptivefilter

Controlalgorithm

m

F

x(n) y(n)

e(n)

+

+

S

m

E

Acoustic/vibrationsystem

Digitalelectronicsystem

Acoustic feedback path

Cancellationpath

estimate

ESR


168/189

Controlsignal

Errorsignal

+

+

Systemidentification

algorithm

Filter

Randomnoise

+

-


169/189

Adaptivealgorithm

Systemidentification

Errorsignal

ControllerA/D

system

A/Dsystem

D/Asystem

Referencesignal

Controlsignal

Electroniccontrol system


170/189

n

Utot

V

z


171/189

z

y

x

U

x

y

67 mm

70 mm 1

2

102 mm


172/189

7

280 mm

680 mm

67 mm

12

11

54

3

104mm

9

8

10


173/189

w

465

d

21 3

7

l

106


174/189

1 10 100 1000

B (kg m-3)

103

104

105

R1

(MK

S

raylsm-1)

d=1

23

4

57

68

1

0

15

12

2.5

1.5

4

68

100

high-frequencyrange


175/189

10-4 10-2 10-1 1 10

10-2

10-3

2

4

68

2

4

68

10-1

2

f c/

f R/ 1

/=

1.0

m

/=

0.1

mlow-frequency

range

mid-frequencyrange

R1 c/ = 2020

24


176/189

10

2

5

1

0.05 0.1 1 10 150

4

8

12

16

20

TL(dB)

f c B/

9

10


177/189

01

2

3

4

5

6

7

8

Refle

ctionloss(dB)

f R/ 1

10-4 10-2 10-110-3 1

100

R c1 / = 10


178/189

1

10

0.01 0.1 1 2 4 106 100

TL(dB)

f R/ 1

2

5

1

0.2

0.5

0.1

graphic


179/189

heavy metal plug

test samplemicrophoneprobe

speaker

microphoneretractingcable

mechanical drivesound level

meter

bandpass

filter

graphiclevel

recorder

amplifieroscillatorfrequency

counter


180/189

0

Z = p ut/ t

x = -L

sample

x

0.25 0.9

5

4


181/189

0 5 10 15 20 25 30 35 40 45 500.500.0

0.450.05

0.400.10

0.350.15

0.300.20

L0 (dB)

D1

/

0.

94

0.93

0.92

0.91

0.9

0.84

0.8

2

0.8

0.7

5

0.7

0.6

5

0.6

0.5

5

0.

5

0.

45

0.

4

0.

35

0.

3

0.

25

0.

2

0.1

8

0.1

6

0.

14

0.1

2

0.1

0.0

9

0.0

8

0.0

7

0.0

6

0.0

5

0.0

4

0.

03

0.0

25

0.0

2

0.0

15

st

=0

.01

0.8

8

0.8

6

al


182/189

Filterinput

sign

Filteroutput

0

0

0

0

+8% -1%

time

+1

0

time t

2


183/189

-1time, t

(a)

(b)

Sum of first fourharmonic components

1

2

3

4

A /4 A / 4A

2 22

k k0

amplitude squared

(a)


184/189

A / 2

A

A

A

A

A

A / 2

2

A

A

2

2

2

2

k

k

0

k

0

0

amplitudesquared

amplitude

-f f

f

f

f

f

f

f

f

k k

k

k

k

0

0

0

0

10 log

10 log

10

10

ref

ref

ref

dBre (d)

(c)

(b)

x(t)time

X(f)'frequency

t- t

(a)


185/189

- f f

- T - /2T T T/2

x(t) time

X(fn)

frequency

1/ =T B

f f0 1f-1

- t t

f- f

(b)

- t t

f- f

f ff /2f /2 sss s

frequency

1/fs

time

X(f)

x(t )k

t tt 0-1 1

(c)


186/189

- T

s s s s

- /2T T/2 T

- /2f- f f /2 f

timex(t )k

X(f )n

Frequency

(d)


187/189

amplitude


188/189

time

time

time

time

(a)

(b)

(c)

(d)

0

10


189/189

T

Flat

HanningAtte

nuation(dB)

20

30

40

50

600 1 0 2 0 4 0 6 0 8 1 2 0 4 0 6 0 8 0 10 0

20dB/decade

60dB/d

eca

de

1

Eng Noise Control Figures

Documents

Transcript of Eng Noise Control Figures