Mechanical properties of ribbon parachute fabrics for cluster submunitions

7/23/2019 Mechanical properties of ribbon parachute fabrics for cluster submunitions

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#echanical roerties of ribbon arachute fabrics for cluster

sub$unitions

% &nal'

(eart$ent of Textile )n*ineerin*,

)rci+es ni-ersit+, 303! /a+seri,

Ture+ Recei-ed Jalluar+ 200 re-ised

recei-ed alld acceted 13 4ril 200

4n atte$t has been $ade to stud+ the load"extension beha-iour of the fabric

for cluster sub$unitions. The effect of 5ar densit+ and fibre t+e on the ribbon

fabric erfor$ance usin* stri tensile and tearin* test data has been studied and


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i$ortant oints for the desi*n of sub$unition arachutes hi*hli*hted. Four

different sa$les 5ere $anufactured usin* ectra7 and ol+ester fibres 5ith

three different 5ea-e t+es, t5o of 5hich 5ere deri-ati-es of lain 5ea-e and the

last one 5as re*ular lain 5ea-e. 489V4 5as also erfor$ed for si*nificance

le-el of the test results. It is found that as the 5ar densit+ increases at core":one

of the fabric, the breain* load and ;oun*'s $odulus increase for stri tensile

testin*.


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" Fi*. I " @luster sub$unitions Cat the botto$ed*es of ictureD 5ith attached ribbon

arachute fro$ the to of $unition C #2>I@# D1


4/12

310

2 #aterials and#ethods

2,1 #aterials

I8(I48 J . FIGR) T)HT.R)., J8) 2006

;a

r

;ar

cou

nt,

dte

x

Table I";arn

roerties

ectra7 1000

>ol+ester

23!

>ol+ester C>)D and ectra7 $ultifila$ent +arns5ere used CTable 1 D. a$les

5ere $anufactured in a narro5

5ea-i n* $achine. >)

$ultifi la$ent 5as used as

5eft +ar for all sa$le

*rous. 8u$bers of 5ar and

5eft ends 5ere et constant

C 1 icsAe$ and !

5arsAe$D. The detailed

sa$le infor$ation is *i-en in

Table 2. Three different

5ea-es Cderi-ati-es of lain

5ea-eD 5ere used. The

deri-ations are based on the

5ar densit+ alon* fabric5idth, instead of differenceson interlacin* oints of 5ar

and 5eft +arns Clie rib

5ea-esD. )ach 5ar +arn

consecuti-el+ interlaced 5ith

a 5eft +ar in a re*ion in the

$iddle of the fabric for certain

len*th Ccore":oneD. Therefore,

the aearance of lain 5ea-e

5as conser-ed. For the 5ea-e

t+e I C?T I D, three 5ar

+arns interlaced 5ith a 5eft

+arn Cthree 5ars er dentD i n

a re*ion i n the $iddle of

fabric for the len*th of 6

$$. For the 5ea-e t+e

2 C?T2D, t5o 5ar +arns

interlaced 5ith a 5eft +arn

Ct5o 5ars er dentD i n a

re*ion i n the $iddle of

fabric for the len*th of 6

$$. For the 5ea-e t+e

3 C?T3D, there is not an+

5ar densit+ difference

alon* the fabric 5idth and

therefore ?T3 is a re*ular

lain 5ea-e fabric. Thi s

re*ion i s centered alon*

the 5idth of fabric CFi*.

2D. Fabric 5idth of

sa$les is around 1 $$

and -aries based on the5ar +arn densit+ alon* the

fabric.

4lthou*h +arn counts

are -er+ close for both

fibre t+es, their fabric

thicnesses are different

because of the nu$ber

of fila$ent er to5

and bulier

characteristics of >) fibre

as co$ared to ectra7


5/12

8u$ber of fila$entAto5 60lti$ate tensile stren*th, *Aden 3

#odulus, *Aden 1320 13

)lon*ation, 2.!

Table 2 " a$le secifications

a$le ?ar ?eft Fabric Fabric

?ea-ecode lhicness 5idth

t+e

$$ $$

4 >) >) 0. 1.0

?TI

G >) >) 0. 1.0

?T2

@ >) >) 0. 1.?T3

( ectra7 >) 0.3 1.?TI

R

e

*

i

o

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h

a

-

i

n

*

r

e

*

u

l

a

r

5ar

d

e

n

s

i

t

+

Cre*ular lain 5ea-eD

A

co

n

@ore":one ha-in*( d ifferent 5arC

3 . densit+ for thel len*th of 6 $$ac A

Fabri@ ?idth

fibre.

Fi*. 2

2.2 #ethods

" Fabric sche$e for

secif+in* 5ardistribution and fabricla+out

Fabric testin* 5as

erfor$ed accordin* to the

rele-ant 4T# standards.

Instron 11 uni-ersal tester

5as used for tear and

tensile tests of fabric usin*

stri $ethod. ince the fabric

surface is s$ooth and rone to

sliin*, the secial

attach$ents 5ere roduced tore-ent slia*e.

tri $ethod C4T# (03D 5as used for the

e-aluation of elon*ation and

breain* force of narro5

fabrics. Fi-e sa$les, 5h i ch

5ere 20 c$ i n l en*th and the

sa$e fabric 5idth as *i-en in

Table 2, 5ere tested. 9nl+

5ar"5ise testin* 5as

erfor$ed. Testin*

$achine 5as set for a

loadin* rate of 300 $$A$in.

The sa$e nu$ber of

sa$les, sa$le len*th and

loadin* rate 5as used for

the tear test C4T# (

2261 D. a$les 5ere cutfro$ the $iddle to the

len*th of $$.


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Fabric thicness 5as $easured

based on the 4T# (1 usin*

the Ja$es


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984%= #)@R9>)RTI) 9F RIGG98>4R4@) fibre.

Fibre t+e deter$ines the

load"extension beha-iour of the

fabric. The strain"stress *rah

CFi*. 3D is steeer for ectraE

fabric Ca$le (D than for

>) fabrics Ca$les 4, G

and @D. The sloe and

breain* beha-iour of

fabrics could also be

obser-ed fro$ Fi*. 3, 5here

a$le ( suddenl+ broen

off at lo5er strain and

therefore ha-in* lo5er

tou*hness. This is attributed

to the hi*her stiffness of

ectraE fibre as

Table 3 "tri testresults


8/12

co$ared to >) fibre.

a$les 4, G and @ ha-e

hi*her tou*hness 5ith lo5er

;oun*'s $odulus CTable 3D.

Relati-el+ lon*er extension:one is obser-ed for a$les 4,

G and @.

tri test results su**est that

the fibre t+e for 5ar +arn

needs to be selected deendin*

on the a-ailable conditions,

5here en-iron$ental factors as

5ell as the releasin* attitude for

$unition should be considered.

Fabrics $ade fro$ ectraE

fibre offer i n co$arable

stiffness and hi*her breain*load, 5hile ha-in* lo5er

tou*hness as co$ared to >)

fibre. @ost issue is also i n

fa-our of >) fibre as 5ell.

Free"ends of the ribbon

fabric are folded and

connected usin* stitchin*

techniKue to ut into

arachute for$. Ribbon

arachute is attached to

sub$unition 5ith a hole in the

$iddle of this stitchin* :one.


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Tear test results

Greain* )ner*+ to

dislace$ent breain* oint

$$J

0. C.6D .1 C0.3D

3.6 C.2D .2 C0.2D

3. C.6!D .21 C0.1 D

6. C.D .2 C0.D

0'1

A II 1

0A

'

L ,I 1

10 MMMM.. M a$e (

!I

a (1

A

2

1 00

0

0

2

10

1

=..

L

iL'N L ' .

'.

,

1 202

)0

60

0

3

20

10

0

)Hensio C$$D 0 2 0 6060 100 120 1016 160 20 220

)

leion C$$D

Fi*O 3 " %oad"extension *rah of each sa$le under

unidirectional tensile loadin* Fi*. " %oad"

extension *rah for tear test


10/12

312 I8(I48 J. FIGR) T)HT. R)., J8) 2006

Table

ourceof

-ari

ation

" 489V 4 chart for ;oun*'s $odulus ofstri test results

dJ # F"-aluc >"-alue F"critical

the ;oun*'s $odulus of

stri test. 4lthou*h the

discreanc+ bet5een the

results of >) and ectra

fibres is hi*h, the anal+sis

concludes that the fibre t+e

is not si*nificant for ener*+

to breain* oint

Get5een 2.! 100 2 1.03.36! 0.0.132!

*rous

?ithin 16.1003 6 2.6322

*rous

Total .01 06

" u$s of sKuares. dJ" (e*rees

of freedo$, # " #ean sKuare, >"

-alue " >robabi lit+ of F -alue, and F"

critical " @ritical -alue of F

Table 6 " 489V4 chart for encr*+ tobreain* o int of tear te st results

ource of #

F"-alue >"-aluc

F"critical -ariation

Gct5een 0.!26 0.!261.662 0.01 606.06

*rous

?ithin 0.1126 0.02!31

*rous

Total 0.633

effect $i*ht beco$e effecti-e

5here ectraE fibre i s less

tou*h than >). 4nother

ossibilit+ can be -er+ $inor

slia*es desite all

cautions taen durin* tearin*

test. The latter $i*ht also

increase bias effect.

Relicated one"5a+

489;4 5as erfor$ed in

order to deter$ine 5hether

differences at the core :one

lead to si*nificance in

breain* load and ;oun*'s

$odulus of lain 5ea-e

fabrics for stri test.

@ontributions of breain* load

and ener*+ to breain* oint

are anal+:ed for tearin*

test. The statistical soft5are

aca*e J#>E 5ase$lo+ed to interret the

exeri$ental data for !

confidence le-el. The results

5ere e-aluated based on

F"ratio and robabilit+ of

F"ratio CrobPFD. The

lo5er the robabilit+ of F"

ratio, the $ore si*nificant

is the -ariable. ?ea-e t+e

is found to be si*nificant

onl+ for ;oun*'s $odulus

taen fro$ stri test.


11/12

5ea-e t+e. Fibre t+e is

found to be si*nificant for

results fro$ tear test. This is

attributed to the hi*her

standard de-iation of the results

*i-en in Table . The 489;4

chart for stri test is *i-en in

Table 6. It should be noted that

5hen the si*nificance le-el of

the results, *i-en in Tables

and 6, are co$ared based on

robabilit+ of F"ratio CrobPF,

it is reali:ed that robPF for

the result in Table is hi*her

than that in Table 6.

@onclusions

The studies sho5 that the

5ar densit+ contributes

hi*her breain* load and

;oun*'s $odulus at stri

testin*. ?ea-e t+e has no

contribution for the

$echanical roerties of fabric

in tear test. 489; 4 sho5s

that the 5ea-e t+e and fibre

t+e are onl+ si*nificant for

the ;oun*'s $odulus results

taen fro$ stri tensile test.

4cno5led*e$ent

The author 5ould lie toareciate the suort fro$

2nd

4ir ul+ and

#aintenance @o$$and,

Ture+.

References

I b"IIlIIAlitiolAs alAd cluster b9lllblets " Rellder afe>rocedures

CR>D Qene-a International@entre for


12/12

Res J, ! C 1 !!D 1 .

)ricsen R < & 9rear % , J 4ircraft, 1 C 1 !0D 26.

>eer ? , J 4 ircraft, 1 C 1 !0D 1 ! .

Mechanical properties of ribbon parachute fabrics for cluster submunitions

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