WELCOME

SQUARE JAMMED FABRIC

By• SANJIT JANA• RAJA BAHADUR PAUL• ANUPAM MULA • MIRAJUL SK

• 3RD YEAR • TEXTILE TECHNOLOGY

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1.Prediction of the maximum sett (density) of fabric and fabric dimensions;

2.Find out relationship between geometrical parameters (picks and ends);

3.Prediction of mechanical properties by combining fabric and yarn properties;

4.Understanding fabric performance (handle and surface effect.

INTRODUCTION

The objectives of fabric geometry is to:

Structure of a woven fabric is defined by weave pattern, thread density, crimp and yarn count

Jammed structure

A woven fabric in which warp & weft yarns

don’t have mobility within the structure as they are in intimate contact with each other are called jammed structure. In such a structure the warp & weft yarns will have minimum thread spacing.

Pierce’s Model

Mathematical Notation for the model

• D1 & d2 - Warp & Weft diameter respectively• D - Sum of circular diameter• h1 & h2 -distance between axes of warp /weft & fabric• p1 & p2 – Thread spacing of warp & weft respectively• c1 & c2 - Crimp of warp & weft • θ1 & θ2 – Max. angle of thread axis to plane of cloth

(radians)• l1 & l2 - Moduler length of warp & weft respectively

Results of Pierce’s Model

Jamming Condition of a fabric

• During jamming the straight portion of the intersecting yarn will vanish so that-

Jamming warp direction Jamming weft direction

l1–Dθ1 = 0 h2 = D(1 –cosθ2)

l1/D = 0 p1= Dsinθ2

So, h1 = D(1 -cosθ1) p2= Dsinθ1

Jamming both warp & weft direction

D = h1 + h2

D = D(1 -cosθ1) + D(1 –cosθ2) Cosθ1 +cosθ2 = 1

Square Fabric

• A truly square fabric has equal diameter of both warp & weft, equal spacing, equal crimp p2= p1 , c1=c2 , h1=h2 , θ1= θ2

D=2d= h1+h2=2*4/3 p √c √c =3/4 * d/p

Square Jammed fabricFor a sq. jammed fabric θ1 =θ2 So,

Cosθ1 +cosθ2 = 1 Cosθ = ½ θ = π/3

p=Dsinθ & l=Dθ

Racetrack Model• In the racetrack model, a and b are maximum and minimum diameters of

the cross-section. The fabric parameters with superscript refer to the zone AB, which is analogous to the circular thread geometry; the parameters without superscript refer to the racetrack geometry, a repeat of this is between C and D.

Then the basic equations will be modified as under:

p2’ = p2 – (a2 – b2)

l1’ = l1 – (a2 – b2) h1 + h2 = B = b1 + b2Also if both warp and weft threads are jammed, the relationship becomes

Crimp of sq. jammed fabric• The crimp in fabric is the most important parameter which influences

several fabric properties such as extensibility , thickness , compressibility and handle. It also decides quantity of yarn required to weave a fabric during manufacturing.

The crimp of a sq. jammed fabric is about 20.9 % we know, Crimp (c) =l/p -1 [p=Dsinθ &l= Dθ ] = Dθ/Dsinθ -1 = θ/sinθ – 1

= π/3/sin π/3 - 1 [θ = π/3] =1.209 -1 = .209 So, c % = 20.9 %

Cover factor of square jammed fabric

• In fabric, cover is considered as fraction of the total fabric area covered by the component yarns.

The fractional cover factor (d/p) = 1/√3 1 X n = 1/√3 28 X √N n/ √N = 16.2 So, cover factor of both warp & weft is 16.2 AC = 2d k1 = k2 =16.2 AB = d And Fabric cover factor is 23 So, BC = √3 d k1 + k2- k1k2/28 = 23 p = √3

d

Relation between warp & weft cover factor

• Where β = d2/d1• For sq. jammed fabric d2 = d1 • So, β = 1

Application of jammed fabric

Jammed fabric are closely woven fabric & find application in water-proof , wind- proof, bullet-proof requirements.

References

• Woven Textiles: Principles, Technologies and Applications :- Edited by K Gandhi

• Woven Textile Structure: Theory and Applications :- By B K Behera, P K Hari