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palný uma,

tra- rutie hno-

THE FRICTION COEFFICIENT OF LINEAR AND AREAL

TEXTILES

Sodomka, L.

Technical university, 46i 17 Liberec, Czech Repubtic

|n the paper the prob|em. of measuring statica| and dynamica| friction coeffient of Ťibers and area| texti|es is

:iťřÍ'Jl';íjř *}il*":''s'r*fůn:Íil"inu"

án

"ni"Jó'.il;ň"

oe

quaniir;Jiňa

ir," ino"'

|n der Arbeit wurde oelóst das Prob|em der Messung eines KoeÍfizients der statischen und dynamischen Reibung von Fasern und F|ácheniextiri"ň.'Ě".i"t áucn oewiesón,-oá" der Reibungs-Koeffizient eine

til:J!"sfi'J;,;Ít.:J*

quantitativ o"""ňióio"n kann mit der Hi|Íe biň"" n"ioun9s-lndexes, der in dieser Parpadotaua upodneua E3MepeEtrÍ xos@$uqnenra cTaT'qecKoro E ,quEaM^Iec*oro Tpe'a' BoJIoKoE u trJIocKEx TeKcTtrJIbEĎD( MaT€ptra'noB. floxalaao, vro xoos$uqne'r TpeEu''o6rra,qaer aun:orporrzeň' koTopylo Mox'o KoJIrqecTBegEo BbIpa3ETb c troMo,'sro o'peÁeJle'Eoro B cTaTbe uEAeKca TpeEE'.

V práci sa rieŠi problém merania súčinite|a statického a dynamického trenia v|áken a p|ošných textí|ií. Je tieŽ

ť:IffT".i.1i*".i':"f3:.:;","

ma anizoiiáJu,.t<ioru ;e-moŽn.

kňtilii"ne

vyjadiovať,pá'o"áu ino"*u íovní

tsa

hrát lbdubký ebo

ibv

tále

l

nelpri

I|€.J

The fríction is one of the many effects p|aying the very significant role not only in

in" tr"

but also in technical, scientific and

teitile p.*i".

tn most

rmportant cases the friction

is beini

met between the so|id material friction materia|s. is being made through the The quantificatión ot trre sotiofriction coefficient, that ís definéd with the Coiltomo friction law [1]. For the Íriction estimation some theoretica|

dea can be used I2!, but for tÁ;

technica|

app|ication

the friction

coeffícient

has to

be measured,

because the friction coefficient

is dependent on all factors appearing in tl.re praxis as

the

geometrica|, physicat,'chemřc"r

áno

surface effects and interaction of surfac""

u*. -

. The

measurlng

of the

coefficient

of

friction material

couple is

exceedingly important and extended

in

texti|e Íie|ds [3,4J,. nametý between fibres and compact sotio máteri"r", itse|f

u"t'í""n

fibres and between area| texti|es. rň tnat paper the rneasurings of the friction coefficient betwlen fibres and arealtextiles are made, on the new simple self developed

and made

tribometer

OaseJ on

the c|assjcal princíp|e

oÍ the s|ope plane

[5,6]. |ts principle is on the fig. 1. At tne

ňeaslre'"nt"

ot th"

coefficient of friction of two Íibres the one

is

put around

the

other

and the

fríction ang|e

at

the beginning oo

and

stopping o"

fibre"motion is rneasured. The statical f" and kinetical f* coefficients of friction has been ca|cu|ated arter tÁe *"tt kno*n Íormu|a, so that

The same measuring technology

has

been

done a|so for the

meásuring

or"ine

friction coefficient oÍ the area| textiles.

bn

the tribometer the coup|e oÍ the Ío||owing fibres and areal texti|es

have been

measured:

Íibres

""rooňl""roon, carbon/glass, carbon/cotton

and areal

textiles:

polypropylen web fabric/polypropylen web fabric, po|ypropylen

web

fabric/óotton,

t'i"t-

Woven, cotton twist woven/cotton twist woven. The areal texti|e Íabric friction coefficients have been a|so

measured in dependence on the

mutual onenratton

of

textiles inorder

to

establish the anisotropy of the friction coefficient. Ťňe iesurts or the measurements are summarised in the following tables.

Table 1

Friction coefficients of Íibres

Friction couple Friction coefficient kinematical carbon/carbon

carbon/glass carbon/cotton cotton/cotton

0.30 0.34 0.64 v,zo

0.20 0.42 0.24

It is

shown that

the

friction coefficient

is

also dependent on the weight which nas oáán.nung on

the put around fiber. The o"ó"ňJ"n""

is approximately línear as it is shown on thefig. 2.

f - 's,k - rl'V. t^^ bs

\?ákna a textil 2(2) 61 .63 (1 995)

(1)

61

(2)

Table 2

Friction coefficient of areal textiles

Fig.

í

Th-e princip|e measuring friction coefÍicient O is the angle of the anisotropy.

0,30

0,2 5

rn (9)

Fig.2

The dependence of the friction coefÍicient f, (statica|) and Í" kinetica|

on the mass weight acting on the overhanged fibre.

The first Íriction couple

has

been shown no anisotropy whi|e

the

a|| other one$ háVe been shown the observable anisotropy

in the

friction coefficient. lf it will be accepted as

a

measure of friction anisotropy the anisotropy index

A

of the friction

A=(f.o-f.,)(f'*+Í''J

Where f.o, f't, are the ma(ima|, minima| va|ues oÍ the friction coeÍficient in dependence on the angle measurements, one can estimate the anisotropy of friction. The anisotropy indexes

A of

friction are introduced in the last column of the table 2. From these va|ues it is seen that Íor the friction coup|e

polypropylen web/polypropylen webs

no anisotropy of the friction coefficient has not been observed.

The

anisotropy

of the other

textile couples differ in anisotropy index with in one order

that

means

the

anisotropy

is in these

cases signiÍicant. The anisotropy of the kinetica| friction coefficient is not so prominent as the anisotropy of the staticalone.

In the paper it has been

shown

that

the triborneter used for the friction coefficient of linear and arealtextiles can be measured.

REFERENCES

1' Moore, D.F.: Princip|es and App|ications Tribo|ogy. Pergamon Press. Oxford, New York, 1975.

2. Buckley, D.H.: Surface effects in adhesion, friction, wear ano

|ubrication. E|sevier, Amďerodam' oxford, New York. 1981 .

3. Howe||, H.c., et a|': Fňction in texti|es. Butterworth ScientiÍic Publications, London, 1959.

4. Schiď' M.J.: Surface characteňstics of fibres and textiles' M.

Dekker, New York, Basel'1975.

5. Sodomka, L.:Tribometer dé|kových a p|ošných útvarů. JMo.

o. Široká, J.: Tribometr pro v|áknové materiá|y. Dip|omová práce VŠsT V Liberci. Textilní Íaku|ta. 1991 .

Frictioncouple Frictioncoefficient

statical

kinetical Anisotropy index A

As

Ak Polypropylen webs/

po|ypropýen webs Po|ypropýen webs/

cotton twist woven Cotton twist woven/

cotton twist woven

0,74

0,58

0,97 not irm 0,65

0,61 rrm 0,5'l

0,003 0,003

0,08 0,003

0,226 0,11

0,07 0,001

(2) 0,54 0,51

-

62 Vlákna a textil 2(2) 61 -63 (1995)

(3)

SoUě|NFEL rŘerví oÉxoyýcH A PloŠtvÝcn rexnuí

Sodomka, L.

Technická univerzita,461 17 Liberec, ČR

..-,_.T.""í sí|y hra1í.velkou Útohu

v

mnoha tech- rrchy'ch ap|ikacích. l*recí v|astnosti jsou. kvantiÍiko- i'ány součinitelem třeni coŽ je vemittázitá ve|ičina,

'která

musí

byt určoviín"

pio

"ětši* ilhnickych

podmínek měřením.

V čÉnku i"-'uu"j-"n"

i"ona

z

moŽných metod měření

soueiniteÉ-ilní

v|áken a p|ošných textilií na

tribomet.

"r"šiňr kšnstrut<ce,

za|oŽeném

na

naktoněné rovině.

Ňa.toňto

trioo- rnetru byly měbny so-ui r1jter9 trenr ;ár<.izolovaných

:1iT"l

ko|mém pňekňŽení,

t"x

í-urái."n tvořící

:]:Š:é

ytYary,iak je znázoměno na ob;.;.. Součíni- le| tření byl určován z tangenty .iňu, ón ktorem se wed| třecí předmět

oo

poňybď

t"t"iicňi

součinite|

lPnl

" tangenty úh|u, pň kerém doš|o k zastavení tb9íh9 tě|.es.a (dynamický

"""činiĚř'řř"ó.

Touto

metodou byly měřeny součinite|é tr"niui'rtouy"n vláken, součinite|é t-ření

mezi

"nrrráwÁi

v|ákny

1

yltnv

sk|eněnými, mezi uhlkouý'iuíár.nv u ou- v|něnou přízí

a

mezi'

bav|něn9u,|ri.i óáb

byly měřeny součinite|e tření

mezí d"or""ňi

tkanin lojvor,oov,]enlpoIypropylen;

eo'eáňři;;/bavIna a

bav|nďbav|na. Měření ukáza|a aniiotropii sou- činitele tření tkanin..

Pro

noonó""ni-"ň'otr.opi"

-:"':Ít"l." tbn1 by! v

č|ánku

'";"J;;

index

anizotropie součinite|e třenl, ktery' 1e mirou ;eno anizotropie.

;ékna a texti! 2(2) -63 (1 995)

AE

References

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