Learning Reflection of Textile Physics II Contents: 1. Fiber Migration 2. Methods Of Fiber Migration 3. Mechanical Properties Of Textile Materials 4. Tensile Properties 5. Flexural Properties 6. Torsional Properties 7. Frictional Properties 8. Details Of Tensile Properties & Flexural Properties

1. GREEN UNIVERSITY OF BANGLADESH
Department Of Textile
ASSIGNMENT
Remarks:
Course Code : TE 306
Course Title : Textile Physics II
Submitted To:
Name : Mr. Md. Ashraful Alam
Designation : Lecturer
Department : Textile
Submitted By:
Name : Md. Rakibul Hassan
ID : 183014057
Section : E1
Department : Textile
Date Of Submission : 03-09-2020
Assignment Topic : Learning Reflection of Mid Term Syllabus

2. TE 306
Textile Physics II
Topics Content On Mid Term:
Here are the main topics content on mid term from Textile Physics II-
1. Fiber Migration
2. Methods Of Fiber Migration
3. Mechanical Properties Of Textile Materials
4. Tensile Properties
5. Flexural Properties
6. Torsional Properties
7. Frictional Properties
8. Details Of Tensile Properties & Flexural Properties
My Learning Reflection In Mid Term:
From mid term syllabus of Textile Physics II I have learnt some a lot of things. Main topic of textile
physics is fiber properties. In mid term syllabus our course teacher taught us about fiber’s mechanical
properties. Now I am sharing my learning reflection from mid term syllabus one by one-
First thing I have learnt is Fiber Migration. Actually the first topic of this course is Fiber Migration.
Fiber Migration:
After giving twist to fiber, they convert into yarn. And then the fibers in the middle try to come out
and the outer fibers try to go in the middle. This coming and going tendency is called Fiber Migration.
According to Textile Institute (UK), The change in distance of a fibre or filament from the axis of a
yarn during production is called fibre migration.
The next what I learnt is effect of fiber migration on yarn properties. That means what kind of factor
that does affect on yarn properties. Obviously, fiber migration does affect on yarn properties. Let See-
Effects Of Fiber Migration On Yarn Properties:
Migration of fibres affects on many properties of yarn. Mainly it affects yarn strength and elongation.
If fibres migrate more then strength of yarn is increased and yarn elongation will be reduced.
Factors Affecting On Fiber Migration:
Five factors that affect on fiber migration. They are-
1. Fiber staple length
2. Yarn tension
3. Mode of spinning
4. Modulus
5. Form of ribbon on ring frame
Methods Of Measuring Fiber Migration:
To measure fiber migration two different experimental methods have been developed by researchers.
There are two methods by which we can measure migration. And they are-
1. Tracer Fiber Technique
2. Cross Sectional Method

3. 1. Tracer Fiber Technique:
First we have to take two different color fiber one deep color & one light color. Then the fibers have
to be dipped in the liquid. The fibers will be swell after dipping. And then we have to look through
microscope if the fiber is bended or not. This is the technique by how we can measure migration.
2. Cross Sectional Method:
We have to take a fiber. And we will cut the fiber along with width. After cutting, we will keep the
fiber under microscope and have a look through microscope by zooming if the fiber is straight or
bended. If the fiber is straight then migration is not done.
Factors That mainly Influnce Fiber Migration:
1. Fiber
2. Yarn
3. Yarn Processing
After fiber migration my learning topic is mechanical properties of textile fibers.
Mechanical Properties Of Textile Fibers:
The mechanical properties of textile fibers are the responses to applied forces and deformations. The
behavior of fibers in processing and the properties of final products are largely depend on these
properties.
Mechanical properties of textile materials can be classified into four classes-
1. Tensile Properties
2. Flexural Properties
3. Torsional properties
4. Frictional properties
1. Tensile Properties:
Behaviours shown by textile material for applying load or tension. Some points of tensile strength:
(a) Breaking load
(b) Tensile strength
(c) Tenacity
(d) Breaking extension
(e) Work of rupture
(f) Work factor
(g) Work recovery
(h) Elasticity
(i) Elastic recovery
(j) Creep
(a) Breaking load:
The load required to break a yarn is called breaking load. Breaking load is usually expressed by
kilogram, pound, newton etc. Breaking load depends on-
1. Fiber type
2. Nature of fyber
3. Crystallinity
(b) Tensile strength:
The term “Tensile” has been derived from the word “Tension”
Tensile Strength =
Force required to break a specimen
Cross−sectional area

4. (c) Tenacity:
Tenacity can be defined as the ratio of breaking load and linear density of specimen. Units of tenacity-
gram/tex, gram/denier, newton/tex etc.
Tenacity =
Breaking load
Liner density
(d) Breaking extension:
The load required to break a specimen is a useful quantity. Breaking extension of a specimen can be
defined as the actual, percentage increase in length upto breaking. So, it can be said that, the length
of a specimen which extends for applying load before breaking is known as breaking extension and
it is usually expressed as the percentage.
Breaking extension (%) =
Elongation at break × 100
Original length of specimen
(e) Work of rupture:
The energy required to break a specimen or total work done for breaking a specimen is termed as
work of rupture and is expressed by the units of joule, calorie etc. If applied force ‘F’ increases the
length of a specimen in small amount by ‘dl’, then we have-
Work done = Force × Displacement
= F × dl
(f) Work factor:
Work factor can be defined as the ratio between work of rupture and the product of breaking load and
breaking elongation.
Work factor =
Work of rapture
Breaking load ×Breaking elongation
(g) Work recovery:
The ratio between work returned during recovery and total work done in total extension is known as
work recovery.
Work recovery =
Work returned during recovery
Total work done in total extension
(h) Elasticity:
It is property of material to regain its original shape after deformation when the external force are
removed.
(i) Elasticity recovery:
The power of recovery from an immediate extension is called as elastic recovery.
Elasticity recovery =
Elastic extension x 100
Total extension

5. (j) Creep:
When load is applied on a textile fibre, an instaneous strain is occurred in the fibre and after that strain
the fibre strain will be lower with passing time that means slow deformation will be occurred. This
type of behavior of textile fibre is known as creep. The formation of crease marks on cloth depends
on creep behaviors of fibres. Creep is usually classified into two classes.
1. Temporary creep: This type of creep is temporarily occurred in fibre. So, after removing load
it is possible for textile fibre to recover it’s original shape. Here, elastic deformation is
occurred and fibre does not break, only molecular chains of fibre get stretched.
2. Permanent creep: This type of creep is permanently occurred in fibre. So, after removing load
it is not possible for textile fibre to recover it’s original shape. Here, plastic deformation is
occurred and molecular chains of fibre break, hence the whole fibre breaks.
Creep and creep recovery:
Creep is the extension with time under constant load. The complimentary effect is relaxation- the
reduction of stress with time under a given extension.
2. Flexural Properties:
The behaviors shown by textile materials (fibre, yarn and fabric), when it is subjected to bending, are
known as flexural properties. Some points of flexural properties-
(a) Flexural rigidity
(b) Bending recovery
(c) Bending modulus
(a) Flexural rigidity:
Flexural rigidity is the resistance of a textile fibre against bending. It can also be defined as the couple
required to bend the fibre to unit curvature. The unit of flexural rigidity is N-mm2
, N-m2
etc.
Flexural rigidity, Rf = 1 x ηЕT2
4∏ρ
Importance of flexural rigidity:
1. The flexural properties are related to handle and drape of fabrics
2. The recovery from bending is a factor of creasing
3. Bending play an important role in the arrangement of fibers in the yarn
4. Bending strength is important in wear
(b) Bending recovery:
The power of recovery from an immediate curvature of textile fiber is known as bending recovery.
For example, nylon of 15 denier shows 100% recovery from a small curvature, whereas only 20%
recovery is obtained from a large curvature.
(c) Bending modulus:
Bending modulus can be defined as the ratio between bending stress and bending strain. Here,ending
strain is usually expressed as degree or radian.
Bending modulus = Bending stress
Bending strain

6. Shape Factor:
Shape factor is a quantity or number that indicates the thickness or cross-section(shape) of a fiber.
Shape factor is usually expressed by
Flexural properties influence:
1. Behaviour of yarn
2. The drape and handle properties of fabrics
3. The recovery from bending
4. The wearness of fabric
5. The arrangement of fiber in the yarns.
3. Torsional Properties:
Behaviors shown by textile materials for applying torsional force. Some points if torsional properties-
(a) Torsional rigidity
(b) Breaking twist
(c) Shear modulus
4. Frictional Properties:
Behaviors shown by textile materials due to causing the friction.
Conclusion:
From my mid term syllabus from “Textile Physics II”, I have learnt a lot of things about Fiber
properties. The most usefull topics that I learnt are Fiber migration, mechanical properties of txtile
fibers etc. After completting my mid term syllabus I am now totally owned all ther knowledge about
fiber migration and meachanical properties of textile fiber. And I hope that this knowledge will be
usefull & will help me in my professional life.
I am hopeful that after Final syllabus of Textile Physics II will acknowledge rest of the knowledge of
Fiber properties. I would like to thanks my course teacher Mr Ashraful Alam once again. Thank you
sir for everything.
---The End---
Submitted by
Md Rakibul Hassan
Id: 183014057