Yarn Structure and Fabric Geometry — Summer 2024

Define and establish relation between contraction factor & retraction factor.

Give classification of yarn.

Derive an equation Retraction factor, Ry = tan2(α/2).

Define term: Poisson ratio and Orthotropic material.

Define with reference to fabric: i. Isotropic ii. Anisotropic.

Explain microscopic method for evaluating yarn diameter with suitable diagram. What is Schwarz’s constant?

Derive the equations for Pierce’s model for the geometry of Plain woven fabric when “Neither of the yarn is straight nor it is jammed”.

Write down list of assumptions made for idealized twist geometry.

State and define various migration parameters along with expressions.

07 Derive equation for twist angle ( ) & twist factor( ),

Define the terms- Packing factor and yarn twist

Explain tracer fibre techniques for migration with diagram.

Write a short note on different ways in which fiber packing occurs in yarns.

Define terms migration and ideal migration.

Write about disturbing factors which causing deviation from ideal structure.

Prove that RMS deviation (D) is 0.3 for ideal and perfect migration.

Give limitation of fabric geometrical model.

Explain the phenomenon of crimp interchange.

Derive generalized equation for maximum cover (reference standard for K & d/p).

For cotton yarn if v = 1.1, warp yarn count is 24’s with 54 end/inch and weft cover factor is 9. Find out the cloth cover.

Explain load extension curve for the fabric with different zones.

Write brief note on Tensile properties of fabric.

Define and state the importance of young modulus.

Elaborate load extension curve for the fabric with different zones.

Explain the geometry of jammed condition for Race track cross-section.