1 1 fundamental physical and technical...

50
1 1 1 Fundamental Physical and Technical Terms 1.1 Units of physical quantities 1.1.1 The International System of Units (Sl) The statutory units of measurement are 1) 1. the basic units of the International System of Units (Sl units) for the basic quantities length, mass, time, electric current, thermodynamic temperature and luminous in- tensity, 2. the units defined for the atomic quantities of quantity of substance, atomic mass and energy, 3. the derived units obtained as products of powers of the basic units and atomic units through multiplication with a defined numerical factor, 4. the decimal multiples and sub-multiples of the units stated under 1-3. Table 1-2 Decimals Multiples and sub-multiples of units Decimal power Prefix Symbol 10 18 Exa E 10 –1 Dezi d 10 15 Peta P 10 –2 Zenti c 10 12 Tera T 10 –3 Milli m 10 9 Giga G 10 –6 Mikro μ 10 6 Mega M 10 –9 Nano n 10 3 Kilo k 10 –12 Piko p 10 2 Hekto h 10 –15 Femto f 10 1 Deka da 10 –18 Atto a Table 1-1 Basic SI units Quantity Units Units Symbol Name Length m metre Mass kg kilogramme Time s second Electric current A ampere Thermodynamic temperature K kelvin Luminous intensity cd candela Quantity of substance mol mole 1) DIN 1301 ABB_11_E_01 13.08.2007 8:16 Uhr Seite 1

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Page 1: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

1

1

1 Fundamental Physical and Technical Terms

1.1 Units of physical quantities

1.1.1 The International System of Units (Sl)

The statutory units of measurement are1)

1. the basic units of the International System of Units (Sl units) for the basic quantitieslength, mass, time, electric current, thermodynamic temperature and luminous in-tensity,

2. the units defined for the atomic quantities of quantity of substance, atomic massand energy,

3. the derived units obtained as products of powers of the basic units and atomicunits through multiplication with a defined numerical factor,

4. the decimal multiples and sub-multiples of the units stated under 1-3.

Table 1-2DecimalsMultiples and sub-multiples of units

Decimal power Prefix Symbol

1018 Exa E 10–1 Dezi d1015 Peta P 10–2 Zenti c1012 Tera T 10–3 Milli m109 Giga G 10–6 Mikro µ106 Mega M 10–9 Nano n103 Kilo k 10–12 Piko p102 Hekto h 10–15 Femto f101 Deka da 10–18 Atto a

Table 1-1

Basic SI units

Quantity Units UnitsSymbol Name

Length m metreMass kg kilogrammeTime s secondElectric current A ampereThermodynamic temperature K kelvinLuminous intensity cd candelaQuantity of substance mol mole

1)DIN 1301

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 1

DEU108193
Textfeld
Die ABB AG übernimmt keinerlei Verantwortung für eventuelle Fehler oder Unvollständigkeiten in diesem Dokument. Vervielfältigung - auch von Teilen - ist ohne vorherige schriftliche Zustimmung durch die ABB AG verboten. Copyright © 2007 by ABB AG, Mannheim Alle Rechte vorbehalten.
Page 2: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

2

Tab

le 1

-3

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

1 L

eng

th, a

rea,

vo

lum

e

1.1

Leng

thm

etre

m

1.2

Are

asq

uare

met

rem

2

are

a1

a =

102

m2

for

land

mea

sure

men

the

ctar

eha

1 ha

= 1

04m

2on

ly

1.3

Volu

me

cub

ic m

etre

m3

litre

l1

l =

1 d

m3

= 1

0–3m

3

1.4

Rec

ipro

cal

reci

pro

cal m

etre

1/m

leng

thd

iop

tre

dp

t1

dp

t =

1/m

1.5

Elo

ngat

ion

met

re p

erm

/mm

etre

(con

tinue

d)

Num

eric

al

valu

e o

fel

onga

tion

ofte

n ex

pre

ssed

in p

er c

ent

only

fo

r re

frac

tive

ind

ex

ofop

tical

sys

tem

s

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 2

Page 3: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

3

1

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

2 A

ngle

2.1

Pla

ne a

ngle

rad

ian

rad

(ang

le)

1 ra

d =

1 m

/m

full

angl

e1

full

angl

e =

2 π

rad

right

ang

le1

= (π

/2) r

ad

deg

ree

°1

°=

(π/1

80) r

adm

inut

e’

1’=

1°/

60se

cond

”1”

= 1

’/60

gon

gon

1 go

n=

(π/2

00) r

ad

2.2

Sol

id a

ngle

ster

adia

nsr

1 sr

= 1

m2 /

m2

see

DIN

131

5

(con

tinue

d)

see

DIN

131

5

In c

alcu

latio

n th

e un

it ra

d a

sa

fact

or c

an b

e re

pla

ced

by

num

eric

al 1

.

⎫ ⎪ ⎪ ⎬ ⎪ ⎪ ⎭

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 3

Page 4: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

4

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

3 M

ass

3.1

Mas

ski

logr

amm

ekg

gram

me

g1

g=

10–3

kgto

nne

t1

t=

103

kgat

omic

u1

u=

1.6

6056

55 ·

10–2

7kg

mas

s un

it

met

ric c

arat

Kt

1 K

t=

0.2

· 10

–3kg

3.2

Mas

s p

er u

nit

kilo

gram

me

kg/m

leng

thp

er m

etre

Tex

tex

1 te

x=

10–6

kg/m

=

1 g

/km

(con

tinue

d)

Uni

ts

of

mas

s ar

e al

sous

ed t

o d

esig

nate

wei

ght

as t

he r

esul

t of

wei

ghin

gq

uant

ities

of

good

s (D

IN13

05)

only

for

gem

s

only

for

tex

tile

fibre

s an

dya

rns,

see

ISO

114

4

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 4

Page 5: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

5

1

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

3.3

Den

sity

kilo

gram

me

kg/m

3se

e D

IN 1

306

per

cub

ic m

etre

3.4

Sp

ecifi

ccu

bic

met

rem

3 /kg

see

DIN

130

6vo

lum

ep

erki

logr

amm

e

3.5

Mas

s m

omen

tki

logr

amm

e-kg

· m

2

of in

ertia

1)sq

uare

met

re

1)S

ee a

lso

note

s on

pag

e 15

.

( con

tinue

d)

see

DIN

130

4-1

and

N

ote

to N

o. 3

.5

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 5

Page 6: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

6

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Qua

ntity

Rel

atio

nshi

pR

emar

ksN

ame

Sym

bol

Nam

eS

ymb

ol

4 T

ime

4.1

Tim

ese

cond

sm

inut

em

in1

min

= 6

0 s

hour

h1

h =

60

min

day

d1

d

= 2

4 h

year

a

4.2

Freq

uenc

yhe

rtz

Hz

1 H

z =

1/s

4.3

Rev

olut

ions

reci

pro

cal

1/s

per

sec

ond

seco

ndre

cip

roca

lm

inut

e1/

min

1/m

in =

1/(

60 s

)

(con

tinue

d)

In t

he p

ower

ind

ustr

y a

year

is t

aken

as

8760

hou

rs.

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 6

Page 7: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

7

1

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

4.4

Cyc

licre

cip

roca

l1/

sfr

eque

ncy

seco

nd

4.5

Velo

city

met

re p

erm

/sse

cond

1ki

lom

etre

km/h

1 km

/h =

—m

/sp

er h

our

3.6

4.6

Acc

eler

atio

nm

etre

per

m/s

2

seco

nd s

qua

red

4.7

Ang

ular

rad

ian

per

rad

/sve

loci

tyse

cond

4.8

Ang

ular

rad

ian

per

rad

/s2

acce

lera

tion

seco

nd s

qua

re

(con

tinue

d)

The

2πfo

ld o

f th

e pe

riod

frequ

ency

is

calle

d an

gula

rfre

quen

cy

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 7

Page 8: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

8

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

1)R

emar

ksN

ame

Sym

bol

Nam

eS

ymb

ol

5 F

orc

e, e

nerg

y, p

ow

er

5.1

Forc

ene

wto

nN

1 N

= 1

kg

m/s

2

5.2

Mom

entu

mne

wto

n-se

cond

N ·

s1

N·s

= 1

· kg

m/s

5.3

Pre

ssur

ep

asca

lP

a1

Pa

= 1

N/m

2

bar

bar

1 b

ar

= 1

05P

a

(con

tinue

d)

Als

o ca

lled

wei

ght

see

DIN

130

5.

see

DIN

131

4

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 8

Page 9: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

9

1

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

1)R

emar

ksN

ame

Sym

bol

Nam

eS

ymb

ol

5.4

Mec

hani

cal

new

ton

per

N/m

2 , P

a1

Pa

= 1

N/m

2

stre

sssq

uare

met

re,

1 M

Pa

= 1

N/m

m2

pas

cal

1 G

Pa

= 1

kN

/mm

2

5.5

Ene

rgy,

wor

k,jo

ule

J1

J=

1 N

m =

1 W

sq

uant

ity o

f hea

t=

1 k

g m

2 /s2

kilo

wat

t-ho

urkW

h1

kWh

= 3

.6 M

Jel

ectr

on v

olt

eV1

eV=

1.6

0219

·10

–19J

5.6

Torq

ue

new

ton-

met

reN

· m

1 N

· m

=

1 J

= 1

W ·

s

5.7

Ang

ular

new

ton-

seco

nd-

N ·

s · m

1 N

· s

· m =

1 k

g · m

2 /s

mom

entu

mm

etre

(con

tinue

d)

see

DIN

134

5

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 9

Page 10: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

10

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

5.8

Pow

erw

att

W1

W =

1 J

/s

ener

gy fl

ow,

=1

N ·

m/s

heat

flow

= 1

V ·

A

6 V

isco

met

ric

qua

ntit

ies

6.1

Dyn

amic

pas

cal-

seco

ndP

a · s

1 P

a · s

= 1

N ·

s/m

2se

e D

IN 1

342

visc

osity

= 1

kg/

(s ·

m)

6.2

Kin

emat

icsq

uare

met

rem

2 /s

see

DIN

134

2vi

scos

ityp

er s

econ

d

(con

tinue

d)

app

aren

t p

ower

(V ·

A)

reac

tive

pow

er (v

ar)

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 10

Page 11: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

11

1

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

7 T

emp

erat

ure

and

hea

t

7.1

Tem

per

atur

e1)ke

lvin

K

deg

ree

Cel

sius

°C

The

deg

ree

Cel

sius

is(c

entig

rad

e)th

e sp

ecia

l nam

e fo

rke

lvin

whe

n ex

pre

ssin

gC

elsi

us t

emp

erat

ures

.

7.2

Ther

mal

squa

re m

etre

m2 /

sse

e D

IN 1

341

diff

usiv

ityp

er s

econ

d

7.3

Ent

rop

y, t

herm

aljo

ule

J/K

see

DIN

134

5ca

pac

ityp

er k

elvi

n

7.4

Ther

mal

w

att

per

W/(

K ·

m)

see

DIN

134

1co

nduc

tivity

kelv

in-m

etre

1)S

ee a

lso

note

s on

pag

e 15

.(c

ontin

ued

)

The

rmo

dyn

amic

te

mp

era-

ture

; see

Not

e to

No.

7.1

and

DIN

134

5.K

elvi

n is

al

so

the

unit

for

tem

per

atur

e d

iffer

ence

s an

din

terv

als.

Exp

ress

ion

of

Cel

sius

te

m-

per

atur

es a

nd C

elsi

us t

em-

per

atur

e d

iffer

ence

s,

see

Not

e to

No

7.1.

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 11

Page 12: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

12

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

7.5

Hea

t tr

ansf

erw

att

per

W/(

K ·

m2 )

see

DIN

134

1co

effic

ient

kelv

in-s

qua

rem

etre

8 E

lect

rica

l and

mag

neti

c q

uant

itie

s

8.1

Ele

ctric

cur

rent

,am

per

eA

see

DIN

132

4m

agne

tic

pot

entia

ld

iffer

ence

8.2

Ele

ctric

vol

tage

,vo

ltV

1 V

=

1 W

/Ase

e D

IN 1

324

elec

tric

pot

entia

l

8 3

Ele

ctric

siem

ens

S1

S

= A

/Vse

e N

ote

to c

olum

ns 3

and

cond

ucta

nce

4 an

d a

lso

DIN

132

4

8.4

Ele

ctric

ohm

Ω1 Ω

= 1

/Sse

e D

IN 1

324

resi

stan

ce

(con

tinue

d)

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 12

Page 13: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

13

1

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

8.5

Qua

ntity

of

coul

omb

C1

C=

1 A

· s

see

DIN

132

4el

ectr

icity

, ele

ctric

amp

ere-

hour

Ah

1 A

· h

= 3

600

A ·

sch

arge

8.6

Ele

ctric

fara

dF

1 F

= 1

C/V

see

DIN

130

4ca

pac

itanc

e

8.7

Ele

ctric

flux

co

ulom

b p

erC

/m2

see

DIN

132

4d

ensi

tysq

uare

met

re

8.8

Ele

ctric

fiel

dvo

lt p

er m

etre

V/m

see

DIN

132

4st

reng

th

8.9

Mag

netic

flux

web

erW

b1

Wb

= 1

V ·

sse

e D

IN 1

324

8.10

Mag

netic

flux

te

sla

T1

T =

1 W

b/m

2se

e D

IN 1

324

dens

ity, (

indu

ctio

n)

8.11

Ind

ucta

nce

henr

yH

1 H

= 1

Wb

/Ase

e D

IN 1

324

(per

mea

nce)

(con

tinue

d)

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 13

Page 14: 1 1 Fundamental Physical and Technical Termsat.dii.unipd.it/renato.gobbo/didattica/corsi/Componenti...4 Table 1-3 (continued) List of units 12345 67 8 Sl unit Other units No. Quantity

14

Tab

le 1

-3 (c

ontin

ued

)

List

of u

nits

12

34

56

78

Sl u

nit

Oth

er u

nits

No.

Q

uant

ityR

elat

ions

hip

Rem

arks

Nam

eS

ymb

olN

ame

Sym

bol

8.12

Mag

netic

fiel

dam

per

eA

/mse

e D

IN 1

324

inte

nsity

per

met

re

9 P

hoto

met

ric

qua

ntit

ies

9.1

Lum

inou

sca

ndel

acd

inte

nsity

9.2

Lum

inan

ceca

ndel

a p

ercd

/m2

see

DIN

503

1 P

art

3sq

uare

met

re

9.3

Lum

inou

s flu

xlu

men

Im1

Im=

1 c

d ·

srse

e D

IN 5

031

Par

t 3

9.4

Illum

inat

ion

lux

Ix1

lx=

1 Im

/m2

see

DIN

503

1 P

art

3

see

DIN

503

1 P

art

3.

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 14

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15

1

Not

es t

o Ta

ble

1-3

To

No

. 3.5

:

Whe

n co

nver

ting

the

so-c

alle

d “

flyw

heel

ine

rtia

GD

2 ” i

nto

a m

ass

mom

ent

ofin

ertia

J, n

ote

that

the

num

eric

al v

alue

of G

D2

in k

p m

2is

eq

ual t

o fo

ur t

imes

the

num

eric

al v

alue

of t

he m

ass

mom

ent

of in

ertia

J in

kg

m2 .

To

No

. 7.1

:

The

(ther

mod

ynam

ic) t

emp

erat

ure

(T),

also

kno

wn

as “

abso

lute

tem

per

atur

e”, i

sth

e p

hysi

cal q

uant

ity o

n w

hich

the

law

s of

the

rmod

ynam

ics

are

bas

ed.

For

this

reas

on,

only

thi

s te

mp

erat

ure

shou

ld b

e us

ed i

n p

hysi

cal

equa

tions

. Th

e un

itke

lvin

can

als

o b

e us

ed t

o ex

pre

ss t

emp

erat

ure

diff

eren

ces.

Cel

sius

(cen

tigra

de)

tem

per

atur

e(t)

( ) i

s th

e sp

ecia

l diff

eren

ce b

etw

een

a gi

ven

ther

mod

ynam

ic t

emp

erat

ure

Tan

d a

tem

per

atur

e of

T0

= 2

73.1

5 K

.

Thus

, t =

T –

T 0=

T –

273.

15 K

.(1

)

Whe

n ex

pre

ssin

g C

elsi

us t

emp

erat

ures

, the

sta

ndar

d s

ymb

ol °

C is

to

be

used

.

The

diff

eren

ce ∆

t b

etw

een

two

Cel

sius

tem

per

atur

es,

e. g

. th

e te

mp

erat

ures

t 1=

T1

– T 0

and

t2

= T

2–

T 0, i

s

∆t

=t 1

–t2

=T 1

– T 2

=∆

T(2

)

A t

emp

erat

ure

diff

eren

ce o

f th

is n

atur

e is

no

long

er r

efer

red

to

the

ther

mo-

dyn

amic

tem

per

atur

e T 0

, an

d h

ence

is n

ot a

Cel

sius

tem

per

atur

e ac

cord

ing

toth

e d

efin

ition

of E

q. (

1).

How

ever

, th

e d

iffer

ence

bet

wee

n tw

o C

elsi

us t

emp

erat

ures

may

be

exp

ress

edei

ther

in

kelv

in o

r in

deg

rees

Cel

sius

, in

par

ticul

ar w

hen

stat

ing

a ra

nge

ofte

mp

erat

ures

, e. g

. (20

±2)

°C

Ther

mod

ynam

ic t

emp

erat

ures

are

oft

en e

xpre

ssed

as

the

sum

of

T 0an

d a

Cel

sius

tem

per

atur

e t,

i. e

. fol

low

ing

Eq

. (1)

T =

T0

+ t

(3

)

and

so

the

rele

vant

Cel

sius

tem

per

atur

es c

an b

e p

ut i

n th

e eq

uatio

n st

raig

htaw

ay. I

n th

is c

ase

the

kelv

in u

nit s

houl

d a

lso

be

used

for t

he C

elsi

us te

mp

erat

ure

(i. e

. fo

r th

e “s

pec

ial

ther

mod

ynam

ic t

emp

erat

ure

diff

eren

ce”)

. Fo

r a

Cel

sius

tem

per

atur

e of

20

°C, t

here

fore

, one

sho

uld

writ

e th

e su

m t

emp

erat

ure

as

T =

T0

+ t

= 2

73.1

5 K

+ 2

0 K

= 2

93.1

5 K

(4)

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 15

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16

1.1.

2 O

ther

uni

ts s

till

in c

om

mo

n us

e; m

etri

c, B

riti

sh a

nd U

S m

easu

res

Som

e of

the

uni

ts li

sted

bel

ow m

ay b

e us

ed f

or a

lim

ited

tra

nsiti

on p

erio

d a

nd in

cer

tain

exc

eptio

nal c

ases

. The

sta

tuto

ry r

equi

rem

ents

var

yfr

om c

ount

ry t

o co

untr

y.

ångs

tröm

Åle

ngth

1 Å

= 0

.1 n

m =

10–1

0 mA

stro

nom

ie u

nit

AE

leng

th1

AE

= 1

49,5

9787

· 10

–9 m

atm

osp

here

phy

sica

lat

mp

ress

ure

1 at

m =

1,0

1325

bar

atm

osp

here

tec

hnic

alat

, ata

pre

ssur

e1

at =

0,9

8066

5 b

arb

arre

lb

bl

volu

me

1 b

bl

= 1

58,9

88 l

Brit

ish

ther

mal

uni

tB

tuq

uant

ity o

f hea

t1

Btu

≈10

55.0

56 J

calo

rieca

lq

uant

ity o

f hea

t1

cal

= 4

.186

8 J

cent

igon

cp

lane

ang

le1

c =

1 c

gon

= 5

π· 1

0–5ra

dd

egre

ed

egte

mp

erat

ure

diff

eren

ce1

deg

= 1

Kd

egre

e fa

hren

heit

°Fte

mp

erat

ure

T K=

273

.15

+ (5

/9) ·

(tF

– 32

)d

ynd

ynfo

rce

1 d

yn =

10–5

Ner

ger

gen

ergy

1 er

g =

10–7

Jfo

otft

leng

th1

ft =

0.3

048

mga

llon

(UK

)ga

l (U

K)

volu

me

1 ga

l (U

K) ≈

4.54

609

· 10–3

m3

gallo

n (U

S)

gal (

US

)liq

uid

vol

ume

1 ga

l (U

S) ≈

3.78

541

· 10–3

m3

gaus

sG

mag

netic

flux

den

sity

1 G

= 1

0–4T

gilb

ert

Gb

mag

netic

pot

entia

l diff

eren

ce1

Gb

= (

10/4

π) A

gon

gp

lane

ang

le1

g =

1 g

on =

5 π

· 10–3

rad

hors

epow

erhp

pow

er1

hp ≈

745.

700

Whu

ndre

dw

eigh

t (lo

ng)

cwt

mas

s1

cwt

≈50

.802

3 kg

inch

(inc

hes)

in, "

leng

th1

in =

25.

4 m

m =

254

· 10

–4m

kilo

gram

me-

forc

e, k

ilop

ond

kp, k

gffo

rce

1 kp

= 9

.806

65 N

≈10

Nkn

otkn

time

1 kn

= 1

sm

/h =

0,5

144

m/s

Ligh

t-ye

arlj

leng

ht1

Lj =

9,4

6053

· 10

15 m

= 6

3240

AE

Uni

t of

mas

sM

Em

ass

1 M

E =

9.8

0665

kg

max

wel

lM

, Mx

mag

netic

flux

1 M

= 1

0 nW

b =

10–8

Wb

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 16

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17

1

met

re w

ater

col

umn

mW

Sp

ress

ure

1 m

WS

= 9

806,

65 P

a ≈

98,0

665

mb

arm

icro

leng

th1

µ=

1 µ

m =

10–6

mm

ilem

ilele

nght

1 m

ile =

160

9,34

4 m

mill

imet

res

of m

ercu

rym

m H

gp

ress

ure

1 m

m H

g ≈

133.

322

Pa

mill

igon

ccp

lane

ang

le1

cc =

0.1

mgo

n =

5 π

· 10–7

rad

oers

ted

Oe

mag

netic

fiel

d s

tren

gth

1 oe

= (

250/π)

A/m

≈80

A/m

ounc

eoz

mas

s1

oz =

28.

3495

gP

ferd

estä

rke,

che

val-

vap

eur

PS

, CV

pow

er1

PS

= 7

35.4

9875

WP

fund

Pfd

mas

s1

Pfd

= 0

.5 k

gp

ieze

pz

pre

ssur

e1

pz

= 1

mP

a =

10–3

Pa

pin

tp

tvo

lum

e1

pt

= 5

68,2

62 m

lp

oise

Pd

ynam

ic v

isco

sity

1 P

= 0

.1 P

a · s

pon

d, g

ram

-for

cep

, gf

forc

e1

p =

9.8

0665

· 10

–3N

≈10

mN

pou

nd1)

Ibm

ass

1 Ib

= 0

,453

5923

7 kg

pou

ndal

pd

lfo

rce

1 p

dl ≈

0.13

8255

Np

ound

forc

eIb

ffo

rce

1 Ib

f ≈

4.44

822

Nse

a m

ile, i

nter

natio

nal

smle

ngth

(mar

ine)

1 sm

= 1

852

msh

ort

hund

red

wei

ght

sh c

wt

mas

s1

sh c

wt

≈45

.359

2 kg

stilb

sblu

min

ance

1 sb

= 1

04cd

/m2

stok

esS

tki

nem

atic

vis

cosi

ty1

St

= 1

0–4m

2 /s

torr

Torr

pre

ssur

e1

Torr

= 1

.333

224

mb

arty

pog

rap

hica

l poi

ntp

leng

th (p

rintin

g)1

p =

(1.

0033

3/26

60) m

≈0.

4 m

mya

rdyd

leng

th1

yd =

0.9

144

mZ

entn

erZ

trm

ass

1 Z

tr =

50

kg

1)U

K a

nd U

S p

ound

s av

oird

upoi

s di

ffer o

nly

afte

r the

six

th d

ecim

al p

lace

.

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 17

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18

Tab

le 1

-4

Met

ric, B

ritis

h an

d U

S li

near

mea

sure

Met

ric u

nits

of l

engt

hB

ritis

h an

d U

S u

nits

of l

engt

h

Kilo

met

reM

etre

Mill

imet

reM

ileYa

rdFo

otIn

chM

il

kmm

mm

mile

ydft

in o

r "

mil

11

000

1 00

0 00

00.

6213

1 09

3.7

3 28

139

370

3 93

7 · 1

04

0.00

11

1 00

00.

6213

· 10

–31.

0937

3.28

139

.370

39 3

700.

0000

010.

001

10.

6213

· 10

–60.

0010

940.

0032

810.

0393

739

.37

1.60

953

1 60

9.53

1 60

9 52

81

1 76

05

280

63 3

606

336

· 104

0.00

0914

0.91

4391

4.32

0.56

82 ·

10–3

13

3636

000

0.30

5 · 1

0–30.

3047

930

4.79

0.18

94 ·

10–3

0.33

331

1212

000

0.25

4 · 1

0–40.

0253

925

.399

70.

158

· 10–4

0.02

777

0.08

331

1 00

00.

254

· 10–7

0.25

4 · 1

0–40.

0253

90.

158

· 10–7

0.02

77·1

0–30.

0833

· 10

–30.

001

1

Sp

ecia

l mea

sure

s:

1 m

etric

nau

tical

mile

= 1

852

m1

Brit

. or

US

nau

tical

mile

= 1

855

m1

met

ric la

nd m

ile =

750

0 m

1 m

icro

n (µ

) = 1

/100

0 m

m =

10

000

Å

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 18

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19

1

Tab

le 1

-5

Met

ric, B

ritis

h an

d U

S s

qua

re m

easu

re

Met

ric u

nits

of a

rea

Brit

ish

and

US

uni

ts o

f are

a

Sq

uare

Sq

uare

Sq

uare

Sq

uare

Sq

uare

Sq

uare

Sq

uare

Sq

uare

Sq

uare

Circ

ular

kilo

met

res

met

red

ecim

.ce

ntim

.m

illim

.m

ileya

rdfo

otin

chm

ils

km2

m2

dm

2cm

2m

m2

sq.m

ilesq

.yd

sq.ft

sq.in

cir.m

ils

11

· 106

100

· 106

100

· 108

100

· 1010

0.38

6013

1 19

6 · 1

0310

76 ·

104

1 55

0 · 1

0619

7.3

· 1013

1 · 1

0–61

100

10 0

001

000

000

0.38

6 · 1

0–61.

1959

10.7

641

550

197.

3 · 1

07

1 · 1

0–81

· 10–2

110

010

000

0.38

6 · 1

0–80.

0119

60.

1076

415

.50

197.

3 · 1

05

1 · 1

0–10

1 · 1

0–41

· 10–2

110

00.

386

· 10–1

00.

1196

· 10

–30.

1076

· 10

–20.

1550

197.

3 · 1

03

1 · 1

0–12

1 · 1

0–61

· 10–4

1 · 1

0–21

0.38

6 · 1

0–12

0.11

96 ·

10–5

0.10

76 ·

10–4

0.00

155

1 97

32.

5899

92

589

999

259

· 106

259

· 108

259

· 1010

130

976

· 10

227

878

· 10

340

145

· 10

55

098

· 1012

0.83

61 ·

10–6

0.83

6130

83.6

130

8 36

1.30

783

6 13

0.7

0.32

28 ·

10–6

19

1296

1 64

6 · 1

06

9.29

0 · 1

0–89.

290

· 10–2

9.29

034

929.

034

92 9

03.4

0.03

58 ·

10–6

0.11

111

114

418

3 · 1

06

6.45

2 · 1

0–10

6.45

2 · 1

0–46.

452

·10–2

6.45

162

645.

162

0.23

96 ·

10–9

0.77

16 ·

10–3

0.00

6940

11.

27 ·

106

506.

7 · 1

0–18

506.

7 · 1

0–12

506.

7·1

0–10

506.

7 · 1

0–850

6.7

· 10–6

0.19

6 · 1

0–15

0.60

7 · 1

0–90.

0054

7·1

0–60.

785

· 10–6

1

Sp

ecia

l mea

sure

s:1

hect

are

(ha)

= 1

00 a

re (a

)1

sect

ion

(sq

.mile

) =

64

acre

s =

2,5

89 k

m2

1ar

e (a

) =

100

m2

1 ac

re =

484

0 sq

.yd

s =

40.

468

aU

SA

1 B

ad. m

orge

n =

56

a =

1.3

8 ac

re1

sq. p

ole

= 3

0.25

sq

.yd

s =

25.

29 m

2

1 P

russ

ian

mor

gen

= 2

5.53

a =

0.6

3 ac

re1

acre

= 1

60 s

q.p

oles

= 4

840

sq.y

ds

= 4

0.46

8 a

1 W

uert

tem

ber

g m

orge

n =

31.

52 a

= 0

.78

acre

1 ya

rd o

f lan

d =

30

acre

s =

121

4.05

a

Brit

.1

Hes

se m

orge

n =

25.

0 a

= 0

.62

acre

1 m

ile o

f lan

d =

640

acr

es =

2.5

89 k

m2

1 Ta

gwer

k (B

avar

ia) =

34.

07 a

= 0

.84

acre

1sh

eet

of p

aper

=

86

x 61

cm

give

s 8

pie

ces

size

A4

or 1

6 p

iece

s A

5or

32

pie

ces

A6

⎫ ⎬ ⎭⎫ ⎬ ⎭

ABB_11_E_01 13.08.2007 8:16 Uhr Seite 19

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20

Tab

le 1

-6

Met

ric, B

ritis

h an

d U

S c

ubic

mea

sure

s

Met

ric u

nits

of v

olum

eB

ritis

h an

d U

S u

nits

of v

olum

eU

S li

qui

d m

easu

re

Cub

icC

ubic

Cub

icC

ubic

Cub

icC

ubic

Cub

icG

allo

nQ

uart

Pin

tm

etre

dec

imet

rece

ntim

etre

mill

imet

reya

rdfo

otin

ch

m3

dm

3cm

3m

m3

cu.y

dcu

.ftcu

.inga

lq

uart

pin

t

11

000

1 00

0 · 1

031

000

· 106

1.30

7935

.32

61 ·

103

264.

21

056.

82

113.

61

· 10–3

11

000

1 00

0 · 1

031.

3079

·10

–30.

0353

261

.023

0.26

421.

0568

2.11

361

· 10–6

1 · 1

0–31

1 00

01.

3079

·10

–60.

3532

· 10

–40.

0610

230.

2642

· 10

–31.

0568

· 10

–32.

1136

· 10

–3

1 · 1

0–91

· 10–6

1 · 1

0–31

1.30

79 ·

10–9

0.35

32 ·

10–7

0.61

0 · 1

0–40.

2642

· 10

–61.

0568

· 10

–62.

1136

· 10

–6

0.76

4573

764.

573

764

573

764

573

·10

31

2746

656

202

808

1 61

60.

0283

170

28.3

1701

28 3

17.0

128

317

013

0.03

7037

11

728

7.48

224

29.9

2896

59.8

5792

0.16

38 ·

10–4

0.01

6387

116

.387

1616

387.

160.

2143

· 10

–40.

5787

· 10

–31

0.00

433

0.01

732

0.03

464

3.78

5 · 1

0–33.

7854

423

785.

442

3 78

5 44

20.

0049

457

0.13

3679

723

11

48

0.94

63 ·

10–3

0.94

6360

594

6.36

0594

6 36

0.5

0.00

1236

40.

0334

199

57.7

50.

250

12

0.47

32 ·

10–3

0.47

3180

247

3.18

0247

3 18

0.2

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750.

125

0.50

01

Con

vers

ion

: 1 in

ch =

0,0

3937

x l/

m

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1.1.3 Fundamental physical constants

Universell gas constant: R = 8.314472 J K–1 mol–1

is the work done by one mole of an ideal gas under constant pressure (1013 hPa) whenits temperature rises from 0 °C to 1 °C.

Avogadro’s constant: NA (Loschmidt’s number NL): NA = 6.0221415 · 1023 mol–1

number of molecules of an ideal gas in one mole.

Base of natural logarithms: e = 2.718282

Bohr’s radius: ao = 0.5291772108 · 10–10 mradius of the innermost electron orbit in Bohr’s atomic model

Boltzmann’s constant: k = 1.3806505 · 10–23 J · K–1

is the mean energy gain of a molecule or atom when heated by 1 K.

Elementary charge: eo = F/NA = 1.60217653 · 10–19 As is the smallest possible charge a charge carrier (e.g. electron or proton) can have.

Electron-volt: eV = 1.60217653 · 10–19 J

Energy mass equivalent: mec2 = 8.1871047 · 10–14 J = 0.510998918 MeVaccording to Einstein, following E = m · c2, the mathematical basis for all observedtransformation processes in sub-atomic ranges.

Faraday’s constant: F = 96485.3383 C · mol–1

is the quantity of current transported by one mole of univalent ions.

Field constant, electrical: ε0 = 0.885418781762 · 10–12 F · m–1

a proportionality factor relating charge density to electric field strength.

Field constant, magnetic: µ0 = 4 · π · 10–7 H · m–1

a proportionality factor relating magnetic flux density to magnetic field strength.

Gravitational constant: γ = 6.6742 · 10–11 m3 · kg–1 · s–2

is the attractive force in N acting between two masses each of 1 kg weight separatedby a distance of 1 m.

Velocity of light in vacuo: c = 2.99792485 · 108 m · s–1

maximum possible velocity. Speed of propagation of electro-magnetic waves.

Mole volume: Vm = 22.710981 · 10–3 · m3 · mol–1

the volume occupied by one mole of an ideal gas at 0 °C and 1013 mbar. A mole is thatquantity (mass) of a substance which is numerically equal in grammes to the molecularweight (1 mol H2 = 2 g H2)

Planck’s constant: h = 6.6260693 · 10–34 J · s a proportionality factor relating energy and frequency of a light quantum (photon).

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Stefan Boltzmann’s constant: σ = 5.6704 · 10–8 W · m–2 · K–4 relates radiant energyto the temperature of a radiant body. Radiation coefficient of a black body.

Temperature of absolute zero: T0 = –273.16 °C = 0 K.

Wave impedance of space: Z0 = 376.73031346152 Ωcoefficient for the H/E distribution with electromagnetic wave propagation.

Z0 = µ0 /ε0 = µ0 · c = 1/ (ε0 · c)

Weston standard cadmium cell: E0 = 1.0186 V at 20 °C.

Wien’s displacement constant: b = 2.8977685 · 10–3 m · Kenables the temperature of a light source to be calculated from its spectrum.

1.2 Physical, chemical and technical values

1.2.1 Electrochemical series

If different metals are joined together in a manner permitting conduction, and both arewetted by a liquid such as water, acids, etc., an electrolytic cell is formed which givesrise to corrosion. The amount of corrosion increases with the differences in potential.If such conducting joints cannot be avoided, the two metals must be insulated fromeach other by protective coatings or by constructional means. In outdoor installations,therefore, aluminium/copper connectors or washers of copper-plated aluminium sheetare used to join aluminium and copper, while in dry indoor installations aluminium andcopper may be joined without the need for special protective measures.

Table 1-7

Electrochemical series, normal potentials in volts, at 25 ºC.

Li/LI+ – 3.05 Mn/Mn2+ – 1.18 Fe/Fe3+ – 0.04K/K+ – 2.93 Zn/Zn2+ – 0.76 H2/H+ 0.00Ba/Ba2+ – 2.91 Cr/Cr3+ – 0.74 Cu/Cu2+ + 0.34Ca/Ca2+ – 2.87 Fe/Fe2+ – 0.44 Cu/Cu+ + 0.52Na/Na+ – 2.71 Cd/Cd2+ – 0.40 Hg/Hg2

2+ + 0.79Mg/Mg2+ – 2.37 In/In3+ – 0.34 Ag/Ag+ + 0.80Be/Be2+ – 1.85 Co/Co2+ – 0.28 Pd/Pd2+ + 0.99Al/Al3+ – 1.66 Ni/Ni2+ – 0.25 Pt/Pt+ + 1.20Ti/Ti2+ – 1.63 Sn/Sn2+ – 0.14 Au/Au3+ + 1.50Zr/Zr4+ – 1.53 Pb/Pb2+ – 0.13 Au/Au+ + 1.70

Note: The electrode designation to the left of the slash indicates the electrode material and to theright of the slash to ion layer which forms in front of the electrode surface (dependent on variousinfluences).

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If two metals included in this table come into contact, the metal mentioned first willcorrode.

The less noble metal becomes the anode and the more noble acts as the cathode. Asa result, the less noble metal corrodes and the more noble metal is protected.

Metallic oxides are always less strongly electronegative, i. e. nobler in the electrolyticsense, than the pure metals. Electrolytic potential differences can therefore also occurbetween metal surfaces which to the engineer appear very little different. Even thoughthe potential differences for cast iron and steel, for example, with clean and rustysurfaces are small, as shown in Table 1-8, under suitable circumstances these smalldifferences can nevertheless give rise to significant direct currents, and hence corrosiveattack.

Table 1-8

Standard potentials of different types of iron against hydrogen, in volts

SM steel, clean surface approx. – 0.40 cast iron, rusty approx. – 0.30cast iron, clean surface approx. – 0.38 SM steel, rusty approx. – 0.25

1.2.2 Faraday’s law

1. The amount m (mass) of the substances deposited or converted at an electrode isproportional to the quantity of electricity Q = l · t.

m ~ l · t

2. The amounts m (masses) of the substances converted from different electrolytes byequal quantities of electricity Q = l · t behave as their electrochemical equivalentmasses M*. The equivalent mass M* is the molar mass M divided by theelectrochemical valency n (a number). The quantities M and M* can be stated ing/mol.

M*m = — l · t

F

If during electroysis the current I is not constant, the product

l · t must be represented by the integral l dt.

The quantity of electricity per mole necessary to deposit or convert the equivalentmass of 1 g/mol of a substance (both by oxidation at the anode and by reduction atthe cathode) is equal in magnitude to Faraday's constant (F = 96480 As/mol).

t2

t1

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Table 1-9

Electrochemical equivalents1)

Valency Equivalent Quantity Approximaten mass2) precipitated, optimum current

g/mol theoretical efficiencyg/Ah %

Aluminium 3 8.9935 0.33558 85 … 98Cadmium 2 56.20 2.0970 95 … 95Caustic potash 1 56.10937 2.0036 95Caustic soda 1 30.09717 1.49243 95Chlorine 1 35.453 1.32287 95Chromium 3 17.332 0.64672 —Chromium 6 8.666 0.32336 10 … 18Copper 1 63.54 2.37090 65 … 98Copper 2 31.77 1.18545 97 … 100Gold 3 65.6376 2.44884 —Hydrogen 1 1.00797 0.037610 100Iron 2 27.9235 1.04190 95 … 100Iron 3 18.6156 0.69461 —Lead 2 103.595 3.80543 95 … 100Magnesium 2 12.156 0.45358 —Nickel 2 29.355 1.09534 95 … 98Nickel 3 19.57 0.73022 —Oxygen 2 7.9997 0.29850 100Silver 1 107.870 4.02500 98 … 100Tin 2 59.345 2.21437 70 … 95Tin 4 29.6725 1.10718 70 … 95Zinc 2 32.685 1.21959 85 … 93

1) Relative to the carbon-12 isotope = 12.000.2) Chemical equivalent mass is molar mass/valency in g/mol.

Example:

Copper and iron earthing electrodes connected to each other by way of the neutralconductor form a galvanic cell with a potential difference of about 0.7 V (see Table 1-7). These cells are short-circuited via the neutral conductor. Their internal resistance isde-termined by the earth resistance of the two earth electrodes. Let us say the sum of allthese resistances is 10 Ω. Thus, if the drop in “short-circuit emf” relative to the “open-circuit emf” is estimated to be 50 % approximately, a continuous corrosion current of35 mA will flow, causing the iron electrode to decompose. In a year this will give anelectrolytically active quantity of electricity of

h Ah35 mA · 8760 — = 306 —– .a a

Since the equivalent mass of bivalent iron is 27.93 g/mol, the annual loss of weightfromthe iron electrode will be

27.93 g/mol 3600 sm = ————————— · 306 Ah/a · ————— = 320 g/a.

96480 As/mol h

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1.2.3 Thermoelectric series

If two wires of two different metals or semiconductors are joined together at their endsand the two junctions are exposed to different temperatures, a thermoelectric currentflows in the wire loop (Seebeck effect, thermocouple). Conversely, a temperaturedifference between the two junctions occurs if an electric current is passed throughthe wire loop (Peltier effect).

The thermoelectric voltage is the difference between the values, in millivolts, stated inTable 1-10. These relate to a reference wire of platinum and a temperature differenceof 100 K.

Table 1-10

Thermoelectric series, values in mV, for platinum as reference and temperaturedifference of 100 K

Bismut ll axis –7.7 Rhodium 0.65Bismut ⊥ axis –5.2 Silver 0.67 … 0.79Constantan –3.37 … –3.4 Copper 0.72 … 0.77Cobalt –1.99 … –1.52 Steel (V2A) 0.77Nickel –1.94 … –1.2 Zinc 0.6 … 0.79Mercury –0.07 … +0.04 Manganin 0.57 … 0.82Platinum ± 0 Irdium 0.65 … 0.68Graphite 0.22 Gold 0.56 … 0.8Carbon 0.25 … 0.30 Cadmium 0.85 … 0.92Tantalum 0.34 … 0.51 Molybdenum 1.16 … 1.31Tin 0.4 … 0.44 Iron 1.87 … 1.89Lead 0.41 … 0.46 Chrome nickel 2.2Magnesium 0.4 … 0.43 Antimony 4.7 … 4.86Aluminium 0.37 … 0.41 Silicon 44.8Tungsten 0.65 … 0.9 Tellurium 50Common thermocouplesCopper/constantan Nickel chromium/nickel(Cu/const) up to 500 °C (NiCr/Ni) up to 1 000 °CIron/constantan Platinum rhodium/(Fe/const) up to 700 °C platinum up to 1 600 °CNickel chromium/ Platinum rhodium/constantan up to 800 °C platinum rhodium up to 1 800 °C

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1.2.4 pH value

The pH value is a measure of the “acidity” of aqueous solutions. It is defined as thelogarithm to base 10 of the reciprocal of the hydrogen ion concentration CH3O1).

c(H+)pH ≡ –log –––––––

mol · L–1

pH scale1 m = 1 mol/ l hydrochloric acid (3.6 % HCl —– 0

0.1 m hydrochloric acid (0.36 % HCl)—–—–—–—–—–—–—–gastric acid—–—–—–—–—–—–—– —– 1

—– 2vinegar ( ≈ 5 % CH3 COOH)—–—–—–—–—–—–—–

—– 3

acidmarsh water—–—–—–—–—–—–—– —– 4

—– 5

—– 6

river water—–—–—–—–—–—–—– —– 7

tap water 20 Ωm—–—–—–—–—–—–—– neutral

—– 8see water 0.15 Ωm (4 % NaCl)—–—–—–—–—–—–—–—– 9

—– 10

0.1 m ammonia water (0.17 % NH3)—–—–—–—–—–—–—– —– 11alkaline

saturated lime-water (0.17 % CaOH2)—–—–—–—–—–—–—– —– 12

0.1 m caustic soda solution (0.4 % NaOH)—–—–—–—–—–—–—– —– 13

⎧⎨⎩

⎧⎨⎩

⎧⎨⎩

Fig. 1-1

pH value of some solutions

1.2.5 Heat transfer

Heat content (enthalpy) of a body: Q = V · ρ · c · ∆ϑV volume, ρ density, c specific heat, ∆ϑ temperature difference

Heat flow is equal to enthalpy per unit time: Φ = Q/t

Heat flow is therefore measured in watts (1 W = 1 J/s).

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Specific heat (specific thermal capacity) of a substance is the quantity of heat requiredto raise the temperature of 1 kg of this substance by 1 °C. Mean specific heat relatesto a temperature range, which must be stated. For values of c and λ, see Section1.2.7.

Thermal conductivity is the quantity of heat flowing per unit time through a wall 1 m2 inarea and 1 m thick when the temperatures of the two surfaces differ by 1 °C. Withmany materials it increases with rising temperature, with magnetic materials (iron,nickel) it first falls to the Curie point, and only then rises (Curie point = temperatureat which a ferro-magnetic material becomes non-magnetic, e. g. about 800 °C forAlnico). With solids, thermal conductivity generally does not vary much (invariable onlywith pure metals); in the case of liquids and gases, on the other hand, it is oftenstrongly influenced by temperature.

Heat can be transferred from a place of higher temperature to a place of lowertemperature by

– conduction (heat transmission between touching particles in solid, liquid orgaseous bodies).

– convection (circulation of warm and cool liquid or gas particles).

– radiation (heat transmission by electromagnetic waves, even if there is no matterbetween the bodies).

The three forms of heat transfer usually occur together.

Heat flow with conduction through a wall:

λΦ = — · A · ∆ϑs

A transfer area, λ thermal conductivity, s wall thickness, ∆ϑ temperature difference.

Heat flow in the case of transfer by convection between a solid wall and a flowingmedium:

Φ = α · A · ∆ϑ

α heat transfer coefficient, A transfer area, ∆ϑ temperature difference.

Heat flow between two flowing media of constant temperature separated by a solidwall:

Φ = k · A · ∆ϑ

k thermal conductance, A transfer area, ∆ϑ temperature difference.

In the case of plane layered walls perpendicular to the heat flow, the thermal conduct-ance coefficient k is obtained from the equation

1 1 sn 1— = —— + —— + –—k α 1

∑ λn α 2

Here, α1 and α2 are the heat transfer coefficients at either side of a wall consisting ofn layers of thicknesses sn and thermal conductivities λn.

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Thermal radiation

For two parallel black surfaces of equal size the heat flow exchanged by radiation is

Φ12 = σ · A (T14–T2

4)

With grey radiating surfaces having emissivities of ε1 and ε2, it is

Φ12 = C12 · A (T14–T2

4)

σ = 5.6704 · 10–8 W · m–2 · K–4 radiation coefficient of a black body (StefanBoltzmann’s constant), A radiating area, T absolute temperature.

Index 1 refers to the radiating surface, Index 2 to the radiated surface.

C12 is the effective radiation transfer coefficient. It is determined by the geometry andemissivity ε of the surface (table 1-12).

Special cases: A1 A2 C12 = σ · ε1

σA1 ≈ A2 C12 = —————

1 1– + – – 1ε1 ε2

Table 1-11

Emissivity ε (average values ϑ < 200 °C)

Black body 1 Oil 0.82Aluminium, polished 0.038 (230 °C) Glass 0,94 (22 °C)Aluminium, raw 0.079 (26 °C) Porcelain, glazed 0,92 (22 °C)Copper, polished 0.049 (23 °C) Water 0.96Copper, oxidized 0.639 (600 °C) Wood (oak) 0,89 (21 °C)Brass, polished 0.059 (19 °C) Roofing felt 0,91 (21 °C)Brass, dull 0.229 (56-338 °C) enamel varnish 0,91 (24 °C)Steel, dull, oxidized 0.969 (26-356 °C) spirit varnish 0,82 (25 °C)Steel, polished 0.29 Soot 0.93

σA2 includes A1 C12 = ————————

1 A1 1– + — · — – 1ε1 A2 ε2

Table 1-12

Heat transfer coefficients α in W/(m2 · K) (average values)

Natural air movement in a closed spaceWall surfaces 10Floors, ceilings: in upward direction 7

in downward direction 5Force-circulated airMean air velocity w = 2 m/s 20Mean air velocity w > 5 m/s 6.4 · w0.75

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1.2.6 Acoustics, noise measurement and noise abatement

Audible sound comprises the mechanical oscillations and waves of an elastic mediumin the frequency range of the human ear between 16 Hz and 20.000 Hz.

Oscillations below 16 Hz are termed infrasound and above 20.000 Hz ultrasound.Sound waves can occur not only in air but also in liquids (water-borne sound) and insolid bodies (solid-borne sound). Solid-borne sound is partly converted into audibleair-borne sound at the boundary surfaces of the oscillating body. The frequency ofoscillation determines the pitch of the sound. The sound generally propagatesspherically from the sound source, as longitudinal waves in gases and liquids and aslongitudinal and transverse waves in solids.

A sound source is characterized by its sound power W. The sound power is the soundenergy radiated by a sound source in unit time. Its unit of measurement is the watt.Sound propagation gives rise to an alternating pressure, the root-mean-square valueof which is termed the sound pressure p. It decreases approximately in proportion tothe square of the distance from the sound source. The sound intensity I is the soundenergy flowing perpendicularly through a surface in unit time; it is therefore a vectorialvalue. Its unit of measurement is the watt/m2.

Since the sensitivity of the human ear is proportional to the logarithm of the soundpressure, a logarithmic scale is used to represent the various types of sound levels.

The sound power level Lw is defined as

Lw = 20 lg W/Wo in dB.

Here: W Sound power radiated from the sound source

Wo Reference power 10–12 W

The sound power level is determined indirectly by measuring sound pressure or soundintensity levels at an enveloping surface surrounding the source. ISO 3740, 3744 to3748 or DIN 45635-1 standards can be applied as general stipulations for determiningthe sound power of machinery, and modified methods have also been developed for aseries of machines. Power transformers are governed by IEC 610076-10 with typicalsound power levels to VDI 3739.

The sound intensity level LI is defined as the logarithm of the ratio of the soundintensity at the measuring point to the reference intensity Io. Measurement isperformed with a sound intensity probe in which two microphones are located at ashort distance opposite each other. The sound intensity in the direction of themicrophone axes is calculated using the sound pressure and the gradients of thesound pressure between the microphones.

LI = 10 lg I/Io in dB

Io The reference intensity 10–12 W/m2

I Measured intensity

The sound intensity measuring method permits determination of the sound powerunder non-ideal conditions, for instance in the presence of interference noise orreflections. Further stipulations on determination of the sound power by the soundintensity method can be found in ISO 9614, Parts 1 and 2.

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The sound pressure level Lp is measured with a sound level meter as the logarithm ofthe ratio of the sound pressure to the reference pressure po. Measurement can beperformed, for example, to IEC 61672-1 and -2.

Lp = 20 lg p/po in dB

Here: po Reference pressure, approximately corresponding to the audible thresholdat 1000 Hz

po 2 · 10–5 N/m2 = 2 · 10–5 Pa

p = Root-mean-square sound pressure

Example:

Sound pressure p = 2 · 10–3 N/m2, measured with a sound pressure meter

Sound level = 20 lg (2 · 10–3) / (2 · 10–5) = 40 dB.

The volume of a noise can be stated as a linear sound pressure level (to DIN 45630,Sheets 1 and 2) or as a frequency-dependent weighted sound pressure level (to DIN45631, E. Zwicker method). The weighted sound pressure levels LA, LB and LC,whichare obtained by switching in defined weighting networks in the sound level meter, arestated in the unit dB with a suffix (A), (B) or (C).

The total sound power level of several sound sources is obtained by adding theirsound powers, i.e. the individual levels are delogarithmized, added and the sumlogarithmized again. Addition of two sound sources of equal strength increases thesound level by 3 dB (example: 2 sound sources of 85 dB together have 88 dB). Withseveral sound sources with different volumes, the volume of the loudest sound sourceis dominant. (Example: 2 sound sources with 80 and 86 dB have a total volume of 87dB.) It follows from this that with two equally loud sound sources both of themattenuate, and with sound sources of different loudness only the louder ones causeattenuation. Every increase in the level by 10 dB causes the perceived loudness todouble, and every reduction by 10 dB causes it to halve.

There are legal limits to permissible noise immissions; in Germany, according to theTechnical Directive on Protection against Noise (TAL) of 26.08.1998, the loudness ofnoises on average must not exceed the following values at the point of immission:

Area Day (6 a.m. - 10 p.m.) Night (10 p.m. - 6 a.m.)dB (A) dB (A)

Industrial 70 70Commercial 65 50Composite 60 45generally residential 55 40Purely residential 50 35Therapy (hospitals, etc.) 45 35

Short-lived, isolated noise peaks can be disregarded (ISO 1996-1, -2, DIN 45641,45645-1). Many standards and regulations, including the TAL, make further allowancesof between 3 dB and 6 dB deducted from the measured sound pressure level fornoises containing tones or pulses. Other limits apply in many other countries. Thereare various methods for assessing the tone content of a noise: one example is that ofDIN 45681.

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1

Disturbing noise is propagated as air-borne and solid-borne sound. When air-bornesound waves strike a wall, some are thrown back by reflection and others areabsorbed by the wall. If air-borne noise striking a wall causes it to vibrate, the wallstransmit the sound into the adjacent space. Solid-borne sound is converted intoaudible air-borne sound by radiation from the boundary surfaces. Ducts, air-shafts,piping systems and the like can transmit sound waves to other rooms. Specialattention must therefore be paid to this when buildings are designed.

Sound pressure and sound intensity decrease with increasing distance from the soundsource. A rough estimate of the sound level Lp(r) to be expected at distance r from asound source with sound power LW can be calculated as follows:

Lp(r) = Lw –10 lg (2π r2)

It is assumed here that the sound source is mounted on a reflecting level surface andthe propagation conditions are otherwise homogeneous.

In the open air, sound propagation is not only affected by distance, but also byreflection and absorption on buildings and plant components, and by the acousticproperties of the ground, by plants and by meteorological influences such as wind andtemperature gradients. ISO 9613-2 and VDI 2714 are often used as guidelines inforecasting sound propagation.

In general, noise emissions must be kept as low as possible at their point of origin. Thiscan often only be achieved by enclosing the noise sources. VDI 2711 provides aguideline for the practical implementation of noise reducing enclosures. The acousticeffect of an enclosure results from a combination of sound reflection from the walls onthe inside, and sound absorption. Without sound absorption, there would be anincrease in sound pressure inside the enclosure as a result of the reflected sound,which would reduce the effectiveness of the enclosure. The most commonly usedsound-absorbent materials are porous substances, plastics, cork, glass fibre andmineral wool, etc. Higher frequency noise components (> approx. 250 Hz) are easier tocombat than lower frequency noises. For noise reduction by more than around 10 dB,not only the choice of materials for the enclosure walls, but also the careful sealing ofall openings, is important. Openings to channel heat and gas are to be fitted withacoustic dampers. A further method of reducing noise immission is to erect anacoustic screen. The effect of an acoustic screen depends on its dimensions, positionand distance from the sound source, distance of the receiver from the edge of thescreen, and the absorption capacity of the wall (see VDI 2720).

When testing walls and ceilings for their behaviour regarding air-borne sound (DIN52210, EN 20140-3, ISO 140-4), one determines the difference D in sound level L forthe frequency range from 100 Hz to 3150 Hz.

D = L1 – L2 in dB where L = 20 lg p/po dB

Here: L1 = Sound level in room containing the sound source

L2 = Sound level in room receiving the sound

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32

Table 1-13

Noise attenuation figures of various construction materials in the range from 100 to3200 Hz

Structural component Attenuation Structural AttenuationdB dB

Brickwork, rendered, 45 Single door without up to 2012 cm thick extra sealingBrickwork, rendered, 50 Single door with good seal 3025 cm thickConcrete wall, 10 cm thick 42 Double door without seal 30Concrete wall, 20 cm thick 42 Double door without extra sealing 40Wood wool mat, 8 cm thick 50 Single window without sealing 15Straw mat, 5 cm thick 38 Spaced double window with seal 30

The reduction in level ∆L, obtainable in a room or enclosure by means of sound-absorbing materials or structures is:

∆L = 10 lg A2/A1 = 10 lg T1/T2 in dB

Here: A Equivalent sound absorption area in the room concerned (frommultiplication of the geometrical areas with their corresponding degrees ofsound absorption )

T Reverberation time of the room in s (Index 1 applies to the untreated room,and index 2 to the room treated with sound-absorbing materials)

Typical degrees of sound absorption a :

Material

Smooth concrete, tiles, masonry 0.05Room with furniture, rectangular machine room 0.15Irregularly shaped room with furniture, machine room 0.2Room with upholstered furniture, room with insulating material on parts of ceiling and walls 0.25Room with insulating material on ceiling and walls 0.35Room with large quantities of insulating material on ceiling and walls 0.5

The equivalent degree of sound absorption of a room can be determined experimen-tally using the reverberation time T:

A = 0,163 V/T in m2

Here: V Room volume in m3

T Reverberation time in s, in which the sound level L falls by 60 dB after soundemission ceases.

When a reduction in noise of approx. 10 dB and more is required, it should also beexamined whether sound can be radiated by other components excited by thetransmission of structure-borne noise. If necessary, the sound source is to be mountedon anti-vibration bearings. These can be simple rubber springs or dissipative steelsprings, depending on the requirements. For high demands, an intermediatefoundation which is also installed on anti-vibration mountings may also be necessary– see also VDI 2062.

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33

1

1.2.

7 Te

chni

cal v

alue

s o

f so

lids,

liq

uid

s an

d g

ases

Tab

le 1

-14

Tech

nica

l val

ues

of s

olid

s

Mat

eria

lD

ensi

tyM

eltin

gB

oilin

gLi

near

Ther

mal

Mea

nS

pec

ific

Tem

per

atur

orp

oint

ther

mal

cond

ucti-

spec

.el

ectr

ical

coef

ficie

nt α

free

zing

exp

ansi

onvi

ty λ

athe

at c

at

resi

stan

ce ρ

of e

lect

rical

poi

ntα

20 °

C0

..10

0 °C

at 2

0 °C

resi

stan

ceat

20

°Ckg

/dm

3°C

°C1)

W/(

m ·

K)

J/(k

g · K

· mm

2 /m

1/K

Alu

min

ium

e.g

. EA

L 99

.5(A

)2.

7065

822

7024

220

920

0.02

876

0.00

42A

l-al

loy

e.g.

EA

I MgS

i(B)

2.70

≈63

023

190

920

0.03

330.

0036

Lead

11.3

432

71

730

2834

130

0.21

0.00

43

Bro

nze

e.g.

CuS

n4P

b4Z

n48.

9≈

930

≈17

.387

377

≈0.

090

0.00

07C

adm

ium

8.64

321

767

31.6

9223

40.

762

0.00

42C

hrom

ium

6.92

180

02

400

8.5

452

0.02

8

Iron,

pur

e7.

881

530

2 50

012

.371

464

0.10

0.00

58Iro

n, s

teel

≈7.

8≈

135

0≈

11.5

4648

50.

25..

0.10

≈0.

005

Iron,

cas

t≈

7.25

≈1

200

≈11

4654

00.

6..

10.

0045

Gol

d19

.29

106

32

700

14.2

309

130

0.02

20

0038

Con

stan

tan

Cu

+ N

i8

..8.

91

600

16.8

2241

00.

48..

0.50

≈0.

0000

5C

arb

on d

iam

ond

3.51

≈3

600

4 20

01.

350

2C

arb

on g

rap

hite

2.25

7.86

571

1

Cop

per

e.g

. Cu-

ETP

R20

08.

921

083

2 33

017

385

393

0.01

754

0.00

392

Mag

nesi

um1.

7465

011

1025

.016

710

340.

0455

0.00

4

1)b

etw

een

0 °C

and

100

°C

(con

tinue

d)

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34

Tab

le 1

-14

(con

tinue

d)

Tech

nica

l val

ues

of s

olid

s

Mat

eria

lD

ensi

tyM

eltin

gB

oilin

gLi

near

Ther

mal

Mea

nS

pec

ific

Tem

per

atur

orp

oint

ther

mal

cond

ucti-

spec

.el

ectr

ical

coef

ficie

nt α

free

zing

exp

ansi

onvi

ty λ

athe

at c

at

resi

stan

ce ρ

of e

lect

rical

poi

ntα

20 °

C0

..10

0 °C

at 2

0 °C

resi

stan

ceat

20

°Ckg

/dm

3°C

°C1)

W/(

m ·

K)

J/(k

g · K

· mm

2 /m

1/K

Bra

ss e

.g. C

uZn3

78.

591

218

120

377

≈0.

0555

0.00

24N

icke

l8.

91

455

3 00

013

8345

2≈

0.12

0.00

46P

latin

um21

.45

177

33

800

8.99

7113

4≈

0.11

0.00

39

Mer

cury

13.5

4638

.83

357

618.

313

90.

698

0.00

08S

ulp

hur

(rho

mb

ic)

2.07

113

445

900.

272

0S

elen

ium

(met

allic

)4.

2622

068

866

351

Silv

er10

.50

960

195

019

.542

123

30.

0165

0.00

36Tu

ngst

en19

.33

380

6 00

04.

5016

713

40.

060.

0046

Zin

c7.

2341

990

716

.50

121

387

0.06

450.

0037

Tin

7.28

232

2 30

026

.767

230

0.11

90.

004

1)b

etw

een

0 °C

and

100

°C

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35

1

Tab

le 1

-15

Tech

nica

l val

ues

of li

qui

ds

Mat

eria

lC

hem

ical

Den

sity

Mel

ting

Boi

ling

Exp

ansi

onTh

erm

alS

pec

ific

Rel

ativ

efo

rmul

orp

oint

at

coef

ficie

ntco

nduc

tivity

heat

cp

die

lect

ricfr

eezi

ng76

0 To

rrx

10–3

λat

20

°Cat

0 °

Cco

nsta

nt ε

r

poi

ntat

180

°C

kg/d

m3

°C°C

at 1

8 °C

W/(

m ·

K)

J/(k

g · K

)

Ace

tone

C3H

6O0.

791

–95

56.3

1.43

2 16

021

.5E

thyl

alc

ohol

C2H

6O0.

789

–11

478

.01.

100.

22

554

25.8

Eth

yl e

ther

C4H

10O

0.71

3–

124

35.0

1.62

0.14

2 32

84.

3

Am

mon

iaN

H3

0.77

1–

77.8

– 3

3.5

0.02

24

187

14.9

Ani

line

C6H

7N1.

022

–6.

218

4.4

0.84

2 06

47.

0B

enzo

leC

6H6

0.87

9+

5.5

80.1

1.16

0.14

1 75

82.

24

Ace

tic a

cid

C2H

4O2

1.04

9+

16.6

511

7.8

1.07

2 03

06.

29G

lyce

rine

C3H

8O3

1.26

–20

290

0.50

0.29

2 42

856

.2Li

nsee

d o

il0.

94–

2031

60.

152.

2

Met

hyl a

lcoh

olC

H4O

0.79

3–

97.1

64.7

1.19

0.21

2 59

531

.2P

etro

leum

0.80

0.99

0.16

2 09

32.

1C

asto

r oi

l0.

970.

691

926

4.6

Sul

phu

ric a

cid

H2S

O4

1.83

4–

10.5

338

0.57

0.46

1 38

5>

84

Turp

entin

eC

10H

160.

855

–10

161

9.7

0.1

1 80

02.

3W

ater

H2O

1.00

1)0

106

0.18

0.58

4 18

788

1)at

4 °

C

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36

Tab

le 1

- 16

Tech

nica

l val

ues

of g

ases

Mat

eria

lC

hem

ical

Den

sity

Mel

ting

Boi

ling

Ther

mal

Sp

ecifi

cR

elat

ive1)

form

ula

ρ1)

poi

ntp

oint

cond

uctiv

ity λ

heat

cp

at 0

°C

die

lect

ricco

nsta

nt ε

rkg

/m3

°C°C

10–2

W/(

m ·

K)

J/(k

g · K

)

Am

mon

iaN

H3

0.77

1–

77.7

–33

.42.

172

060

1.00

72E

thyl

ene

C2H

41.

260

–16

9.4

–10

3.5

1.67

1 61

11.

0014

56A

rgon

Ar

1.78

4–

189.

3–

185.

91.

7552

31.

0005

6

Ace

tyle

neC

2H2

1.17

1–

81–

83.6

1.84

1 51

1B

utan

eC

4H10

2.70

3–

135

–0.

50.

15C

hlor

ine

Cl 2

3.22

0–

109

–35

.00.

0850

21.

97

Hel

ium

He

0.17

8–

272

–26

8.9

1.51

5 23

31.

0000

74C

arb

on m

onox

ide

CO

1.25

0–

205

–19

1.5

0.22

1 04

21.

0007

Car

bon

dio

xid

eC

O2

1.97

7–

56–

78.5

1.42

819

1.00

095

Kry

pto

nK

r3.

743

–15

7.2

–15

3.2

0.88

Air

CO

2fr

ee1.

293

–19

4.0

2.41

1 00

41.

0005

76M

etha

neC

H4

0.71

7–

182.

5–

161.

73.

32

160

1.00

0953

Neo

nN

e0.

8999

–24

8.6

–24

6.1

4.6

Ozo

neO

32.

22–

252

–11

2P

rop

ane

C2H

82.

019

–18

9.9

–42

.6

Oxy

gen

O2

1.42

9–

218.

83–

192.

972.

461

038

1.00

0547

Sul

phu

r he

xaflu

orid

eS

F 66.

072)

–50

.83)

–63

1.28

2)67

01.

0021

2)

Nitr

ogen

N2

1.25

0–

210

–19

5.81

2.38

1042

1.00

0606

Hyd

roge

nH

20.

0898

–25

9.2

–25

2.78

17.5

414

235

1.00

0264

1)at

0 °

C a

nd 1

013

mb

ar2)

at 2

0 °C

and

101

3 m

bar

3)

at 2

.26

bar

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37

1

1.3 Strength of materials

1.3.1 Fundamentals and definitions

External forces F acting on a cross-section A of a structural element can give rise totensile stresses (σz), compressive stresses (σd), bending stresses (σb), shear stresses(τs) or torsional stresses (τt). If a number of stresses are applied simultaneously to acomponent, i. e. compound stresses, this component must be designed according tothe formulae for compound strength. In this case the following rule must be observed:

Normal stresses σz. σd. σb,Tangential stresses (shear and torsional stresses) τs, τt.

are to be added arithmetically;

Normal stresses σb with shear stresses τs,Normal stresses σb with torsional stresses τt,

are to be added geometrically.

Fig. 1-2

Stress-strain diagram, a) Tensile test with pronounced yield point, material = structuralsteel; b) Tensile test without pronounced yield point, material = Cu/Al, ε Elongation,σ Tensile stress, σs Stress at yield point, σE Stress at proportionality limit, Rp02 Stresswith permanent elongation less than 0.2 %, σB Breaking stress.

Elongation ε = ∆ l/l0 (or compression in the case of the compression test) is foundfrom the measured length l0 of a bar test specimen and its change in length ∆ l = l – l0

in relation to the tensile stress σz, applied by an external force F. With stresses belowthe proportionality limit σE elongation increases in direct proportion to the stress σ(Hooke’s law).

Stress σE σEThe ratio ———————— = —– = E is termed the elasticity modulus.Elongation ε εE

E is an imagined stress serving as a measure of the resistance of a material todeformation due to tensile or compressive stresses; it is valid only for the elasticregion.

E is determined in terms of the load σ0.01, i.e. the stress at which the permanentelongation is 0.01 % of the measured length of the test specimen.

a) b)

σE

⎪↓

⎪↓

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38

If the stresses exceed the yield point σs, materials such as steel undergo permanentelongation. The ultimate strength, or breaking stress, is denoted by σB, although a bardoes not break until the stress is again being reduced. Breaking stress σB is related tothe elongation on fracture εB of a test bar. Materials having no marked proportionallimit or elastic limit, such as copper and aluminium, are defined in terms of theso-called Rp0.2-limit, which is that stress at which the permanent elongation is 0.2 %after the external force has been withdrawn.

For reasons of safety, the maximum permissible stresses, σmax or τmax in the materialmust be below the proportional limit so that no permanent deformation, such aselongation or deflection, persists in the structural component after the external forceceases to be applied.

Table 1-17

Material Elasticitymodulus E1)

kN/mm2 2)

Steel 191-224Cast iron 110-140Bronze, CuAl5 123Copper e.g. Cu-ETP 110Al-alloy EAl MgSi(B) 70Aluminium EAl 99,5(A) 65Magnesium alloy MgMn2 45Lead 16

1) Typical values 2) 1 kN/mm2 = 1 GPa

Fatigue strength (endurance limit) is present when the maximum variation of a stressoscillating about a mean stress is applied “infinitely often” to a loaded material (at least107 load reversals in the case of steel) without giving rise to excessive deformation orfracture.

Cyclic stresses can occur in the form of a stress varying between positive and negativevalues of equal amplitude, or as a stress varying between zero and a certain maximumvalue. Cyclic loading of the latter kind can occur only in compression or only in tension.

Depending on the manner of loading, fatigue strength can be considered as bendingfatigue strength, tension-compression fatigue strength or torsional fatigue strength.Structural elements which have to withstand only a limited number of load reversalscan be subjected to correspondingly higher loads. The resulting stress is termed thefatigue limit.

One speaks of creep strength when a steady load with uniform stress is applied,usually at elevated temperatures.

1.3.2 Tensile and compressive strength

If the line of application of a force F coincides with the centroidal axis of a prismatic barof cross section A (Fig.1-3), the normal stress uniformly distributed over the cross-

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39

1

section area and acting perpendicular to it is

Fσ = — .A

With the maximum permissible stress σmax for a given material and a given loading, therequired cross section or the maximum permissible force, is therefore:

FA = ——— or F = σmax · A.σmax

Example:

A drawbar is to be stressed with a steadyload of F = 180 000 N.

The chosen material is structural steel St 37 with σmax = 120 N/mm2.

Required cross section of bar:

E 180 000 NA = ——— = ———————— = 1500 mm2.

σmax 120 N/mm2

Round bar of d = 45 mm chosen.

1.3.3 Bending strength

The greatest bending action of an external force, or its greatest bending moment M,occurs at the point of fixing a in the case of a simple cantilever, and at point c in thecase of a centrally loaded beam on two supports.

Fig. 1-4

Maximum bending moment at a: M = F · l; bei c: M = F · l/4

In position a and c, assuming the beams to be of constant cross section, the bendingstresses σb are greatest in the filaments furthermost from the neutral axis. M may begreater, the greater is σmax and the “more resistant” is the cross-section. The followingcross sections have moments of resistance W in cm, if a, b, h and d are stated in cm.

The maximum permissible bending moment is M = W · σmax and the required momentof resistance

MW = —–— .σmax

Fig. 1-3

l

F

l/2 l/2

l

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40

Example:

A mild-steel stud σmax = 70 N/mm2 with an unsupported length of

l = 60 mm is to be loaded in the middle with a force F = 30 000 N. Required momentof resistance is:

M F · l 30 000 N · 60 mmW = ————— = ————— = ——————————— = 6.4 · 103 mm3.

σmax 4 · σmax 4 · 70 N/mm2

According to Table 1-21, the moment of resistance W with bending is W ≈ 0.1 · d 3.

The diameter of the stud will be: d =310 W, d =

364 000 mm = 40 mm.

1.3.4 Loadings on beams

Table 1-18

Bending load

Case Reaction force A, B max. Deflection fBending permissible moment M load F, Q

F l F l3A = F W = ——— f = ———

σzul 3 E J

σzul WMmax = F l F = ———— —

l

Q l Q l3A = Q W = ———— f = ———

2 σzul 8 E J

Q l 2 σzul WMmax = —— Q = ————— —

2 l

F F l F l3A = B = — W = ——— f = ————

2 4 σzul 48 E J

F l 4 σzul WMmax = —— F = ————— —

4 l

Q Q l 5 Q l3A = B = — W = ———— f = —— · ——

2 8 σzul 384 E J

Q l 8 σzul WMmax = —— Q = ————— —

8 l

l

l

l

l

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41

1

Table 1-18 (continued)

Bending load

Case Reaction force A, B max. Deflection fBending permissible moment M load F, Q

F b F a 2 b 2A = —— f = —————

l 3 E J l

F a σzul W lB = —— F = —————

l a b

F · a · bMmax = ————l

F aA = B = F f = ———— · [3 (l + 2 a) 2 – 4 a2]24 E J

σzul WMmax = F a F = ————

a

F1 e + F2 c A a F1 a2 e2+ F2l2 d2

A = ——————— W1 = ——— f = ————————l σzul 3 E J l

F1 a + F2 d B cB = ——————— W2 = ———

l σzul

determine beam forgreatest “W“

W selection modulus (bending)

F Single point load, Q Uniformly distributed load, J axial angular impulse

E elasticity modulus of material

Q Q l Q l3A = B = — W = ———— f = —— — · ——

2 12 σzul E J 384

Q l 12 σzul WMmax = —— Q = ——————

12 l

l

l

l

l

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42

1.3.5 Buckling strength

Thin bars loaded in compression are liable to buckle. Such bars must be checked bothfor compression and for buckling strength. Buckling strength is calculated with Euler'sformula, a distinction being drawn between four cases.

Table 1-19

Buckling

Case I

One end fixed, other end free

Case II

Both ends free to move along bar axis

Case III

One end fixed, other end free to movealong bar axis

Case IV

Both ends fixed, movement alongbar axis

E Elasticity modulus of material s Factor of safety:J Minimum axial angular impulse for cast iron 8,F Maximum permissible force for mild carbon steel 5,I Length of bar for wood 10.

l l

l l

π2 E JF = ————

4 s l2

4 π2 E JF = ————

s l2

( π )2E J

F = ——————s l2

π2 E JF = ————

s l2

0.7

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43

1

1.3.6 Maximum permissible buckling and tensile stress for tubular rods

Threaded steel tube (gas pipe) or seamless steel tube

10 E 10 E D4 – d4 D 4 – d 4

Fbuck = ——— · J = ——— · ————— where J ≈ ———— from Table 1-22s l2 s l2 20 20

Ften = A · σmax

in which F ForceE Elasticity modulus (= 210 kN/mm2

J Axial angular impulse in cm4

s Factor of safety (= 5)σmax Max. permissible stress (= 350 N/mm2)A Cross-section areaD Outside diameterd Inside diameterl Length

Fig. 1-5

Table 1-20

Nomi- Dimensions Cross- Moment Weight Fbuck for tube length l ≈ Ften

nal dia- sec- of ofmeter tions inertia tube

D D a A J 0.5 m 1 m 1.5 m 2 m 2.5 m 3 minch mm mm mm2 cm4 kg/m kN kN kN kN kN kN kN

10 ³⁄8 17.2 2.35 109.6 0.32 0.85 5.26 1.31 0.58 0.33 0.21 0.15 7.6715 ¹⁄₂ 21.3 2.65 155.3 0.70 1.22 11.69 2.92 1.30 0.73 0.47 0.32 10.8720 ³⁄₄ 26.9 2.65 201.9 1.53 1.58 25.48 6.37 2.83 1.59 1.02 0.71 14.13

25 1 33.7 3.25 310.9 3.71 2.44 61.84 15.46 6.87 3.87 2.47 1.72 21.760.8 25 2 144.5 0.98 1.13 16.34 4.09 1.82 1.02 0.65 0.45 10.120.10431.8 2.6 238.5 2.61 1.88 43.48 10.87 4.83 2.72 1.74 1.21 16.70

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1.3.7 Shear strength

Two equal and opposite forces F acting perpendicular to the axis of a bar stress thissection of the bar in shear.

FThe stress is τs = —;

A

For for given values of F and τs max, the required cross section is A = –——–

τs zul

Fig. 1-6

Pull-rod coupling

Stresses in shear are always combined with a bending stress, and therefore thebending stress σb has to be calculated subsequently in accordance with the followingexample.

Rivets, short bolts and the like need only be calculated for shear stress.

Example:

Calculate the cross section of a shackle pin of structural steel, with Rp 0.2 min = 300 N/mm2 and τs max = 0.8 Rp 0.2 min, for the pull-rod coupling shown in Fig. 1-6.

1. Calculation for shear force:

F 150 000 NA = ———— = ————————————— = 312 mm2

2 τs max 2 · (0.8 · 300) N/mm2

yields a pin diameter of d ≈ 20 mm, with W = 0.8 · 103 mm3 (from W ≈ 0.1 · d 3, seeTable 1-21).

F = 15 000 kp ≈ 1.5 · 105 N

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2. Verification of bending stress:

The bending moment for the pin if F l/4 with a singlepoint load, and F l/8 for a uniformly distributed load. The average value is

F l F l—— + ——

4 8 3Mb = ———————— = — F l

2 16

when F = 1.5 · 105 N, l = 75 mm becomes:

3Mb = —— · 1.5 · 105 N · 75 mm ≈ 21 · 105 N · mm;

16

Mb 21 · 105 N · mm NσB = –— = —————————— ≈ 2,63 · 103 ———W 0,8 · 103 mm3 mm2

i. e. a pin calculated in terms of shear with d = 20 mm will be too weak. The requiredpin diameter d calculated in terms of bending is

Mb 21 · 105 N · mmW= ——— = —————————— = 7 · 103 mm3 = 0.7 cm3

σmax 300 N/mm2

d ≈310 · W =

310 · 7 · 103 mm3 = 41,4 mm ≈ 42 mm.

i. e. in view of the bending stress, the pin must have a diameter of 42 mm instead of20 mm.

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1.3.8 Moments of resistance and moments of inertia

Table 1-21

Cross- Moment of resistance Moment of inertiasection torsion bending1) polar1) axial2)

W 4) W 4) Jp J

0.196 d 3 0.098 d 3 0.098 d 4 0.049 d 4

≈ 0.2 d 3 ≈ 0.1 d 3 ≈ 0.1 d 4 ≈ 0.05 d 4

D 4 – d 4 D 4 – d 4 0.098 (D4– d4) 0.049 (D 4 – d 4)0.196 ———— 0.098 ————

D D

0.208 a3 0.118 a3 0.141 a 4 0.083 a 4

0.208 k1 b 2 h 3) 0.167 b h2 0.141 · k2 b4 0.083 b h 3

B H 3 – b h 3 B H 3 – b h 3——————— ———————

6 H 12

B H 3 – b h 3 B H 3 – b h 3——————— ———————

6 H 12

B H 3 – b h 3 B H 3 – b h 3——————— ———————

6 H 12

b h 3 + bo ho3 b h 3 + bo ho

3——————— ———————

6 h 12

1) Referred to CG of area.2) Referred to plotted axis.3) Values for k: if h : b = 1 1.5 2 3 4

———————————————————— ———-----then k1 = 1 1,11 1,18 1,28 1,36then k2 = 1 1,39 1,62 1,87 1,99

4) Symbol Z is also applicable, see DIN VDE 0103

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1.4 Geometry, calculation of areas and solid bodies

1.4.1 Area of polygons

Regular polygons (n angles)The area A, length of sides S and radii of the outerand inner circles can be calculated using the angle αand the number of sides n. (α = 360 ˚/n).

Irregular polygons

g1 h1 g 2 h 2A = ——— + ——— + …2 2

1= – (g1 h1 + g 2 h 2 + …)

2

Pythagoras theorem

c 2 = a 2 + b 2; c = a 2 + b 2

a 2 = c 2 – b 2; a = c 2 – b 2

b 2 = c 2 – a 2; b = c 2 – a 2

nA/S2 = – cot (α/2)

4

A/r2 = n tan (α/2)

nA/R2 = –– sin α

2

S/R = 2 sin (α/2)

R/r = cos (α/2)

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1Triangle A = – a h U = a + b + c

2 1e = – h3

a + bTrapezium A = ——— · h U = a + b + c + d

2 h a + 2 be = – · ————

3 a + b

Rectangle A = a b U = 2 (a + b)

b r αCircle A = —— = —— r2 π U = 2 r + bsegment 2 180

α 2 sin α 180b = r π —— e = – r ——— · ———

90 3 α π

1A = – π r2 U = r (2 + π) ≈ 5,14 r

2 4 re = – · – = 0,425 r

3 π

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1.4.2 Areas and centres of gravity

Table 1-22

Shape of surface A = area U perimeterS centre of gravity (cg)e distance of cg

Semicircle

Circle

Annularsegment

Semi-annulus

Annulus

Circularsegment

Ellipse

d 2

A = r 2 π = π — U = 2 π r = π d4

π αA = —— α (R 2 – r 2) U = 2 (R – r) + π · —– (R + r)

180 90

2 R 2 – r 2 sin α 180e = – · ———— · ——— · ——

3 R2 – r 2 α π

π 4 R2 + R · r + r2A = —— α (R 2 – r 2) e = — · ————————

2 3 π R + r

A = π (R 2 – r 2) U = 2 π (R + r)

r2 π · α π r αA = —— ––––– - sin 2α U = 2 r 2 – h 2 + ————

2 90 90

s = 2 r 2 – h 2s 2

e = ————12 · A

a b πA = —— π U = – 1,5 (a + b) – ab 4 2

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1.4.3 Volumes and surface areas of solid bodies

Table 1-23

Shape V volume O Surfaceof body A base surface

M Nappe

Solid V = a b c O = 2 (a b + a c + b c)rectangle

d 3Cube V = a3 = ——— O = 6 a2 = 3 d 2

2.828

Prism V = A h O = M + 2 A

Pyramid 1V = – A h O = A + M

3

1Cone V = – A h O = π r (r + s)

3 s = h2 + r2

Truncated π h O = (R + r) π s + π (R2 + r2)cone V = (R 2 + r 2 + R r) · —–

3 s = h2 + (R – r)2

Truncated 1pyramid V = – h (A + A1 + AA1) O = A + A1 + M

3

4Sphere V = – π r 3 O = 4 π r 2

3

2Hemisphere V = – π r 3 O = 3 π r 2

3

1Spherical V = π h 2 r — – h O = 2 π r h + π (2 r h – h 2) =segment 3 π h (4 r – h)

2Spherical V = – π r 2 h π rsector 3 O = —— (4 h + s)

2(continued)

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Table 1-25 (continued)

Shape V Volume O Surfaceof body A Area

Zone π h O = π (2 r h + a 2 + b 2)of sphere V = —— (3a 2 + 3b 2 + h 2)

6

h + h1Obliquely V = π r 2 ———— O = π r (h + h1) + A + A1cut cylinder 2

2 πCylindrical V = – r 2 h 0 = 2rh + – r 2 + Awedge 3 2

Cylinder V = π r 2h O = 2 π r h + 2 π r2

Hollow V = π h (R 2 – r 2) O = 2π h (R + r) + 2π (R2 – r2)cylinder

π D + d πBarrel V = — l · O = ————π d + – d 2

15 2 2(2 D 2 + Dd + 0.75 d 2) (approximate)

Body of ro- V = 2 π A O = circumference of cross-tation (ring) A = cross-section section x 2 π

50

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