When the fiber absorb water they change dimentinally ( Length, Diameter, Area ). Swelling occurs in transvers direction ( width wise ) and Axial direction ( Lengthwise). It can be expressed in term of increase in Diameter, length, area and volumes. That means the dimensionally changes due to absorbing water or moisture by any fiber is termed as sweeling property.

Types of Swelling :

• Transverse Dia Swelling
• Transverse Area Swelling
• Axial Swelling
• Volume Swelling

1.Transverse dial swelling: Fractional increase in diameter of a fiber after swelling is called transverse dia swelling. Mathematically,

Transverse dia swelling, S_D = ∆D / D

Where, D = original diameter of fiber, ∆D =increased diameter of swollen fiber.

2.Transverse area swelling: Fractional increase in area of a fiber after swelling is called transverse area swelling.

Mathematically,

Transverse area swelling, S_A = ∆A / A

Where, A = original area of fiber, ∆A =increased area of swollen fiber.

3.Axial swelling: Fractional increase in length of a fiber after swelling is called axial swelling.

Mathematically, Axial swelling, S_L = ∆L / L

Where, A = original length of fiber, ∆L =increased length of swollen fiber.

4.Volume swelling: Fractional increase in volume of a fiber after swelling is called volume swelling.

Mathematically,

Volume swelling, S_V = ∆V / V

Where, V = original Volume of fiber, ∆V =increased volume of swollen fiber.

Relation between S_A & S_D:      

We know that,

Transverse area swelling, S_A = ∆A / A

Transverse dia swelling, S_D = ∆D / D

For a circular fiber, area A = (π/4)D²

For a swollen fiber, we get, A+∆A = (π/4)(D+∆D)

= (π/4)(D² + 2D. ∆D + ∆D²)

Now,

S_A = ∆A / A

= (A+∆A-A) / A

= {(π/4) (D² + 2D. ∆D + ∆D²) – (π/4) D2^}/ (π/4) D2

= (π/4) (D² + 2D. ∆D + ∆D² – D²⁾ / (π/4) D2

= (2D. ∆D + ∆D²) / D²

= (2D. ∆D / D²) + (∆D²/ D²)

= 2(∆D / D) + (∆D²/ D²)

= 2 S_D + S_D²

So, S_A = 2 S_D + S_D².

Relation between S_A ,S_V & S_L:

We know that,

Transverse area swelling, S_A = ∆A / A

Volume swelling, S_V = ∆V / V

Axial swelling, S_L = ∆L / L

For a circular fiber, volume, V=AL

For a swollen fiber, we get, V +∆V = (A +∆A )(L +∆L)

= AL + A∆L + ∆AL + ∆A ∆L

Now, S_V = ∆V / V

=(V+ ∆V – V) / V

=( AL + A∆L + ∆AL + ∆A ∆L – AL)/AL

= ∆L / L+ ∆A/ A + ∆A/ A. ∆L / L

= S_L + S_A + S_L. S_A 

So, S_V = S_L + S_A + S_L. S_A.

I am Very interested in blogging. Its my passion and hobby. I like playing different games also. The above i only about my leisure time. I am a Wash technician working in Kenpark Bangladesh PVT. Ltd. I passed from Daffodil International University with a certificate of B.Sc in Textile Engineering.

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