This slide shows tensile properties of textile fiber

1. Presentation on Tensile
Properties of Textile Fiber
Prepared by
Name : Shaharia Ahmed
School : Textile Science and Engineering
College : Zhongyuan University of
Technology

2. LAY OUT
Definition
Factors determining the results
of tensile experiments
Expressing the results
Work of rupture
Work factor
Yield point
 Direct measurement of work of rupture
 Experimental methods
 Tensile properties of Fibre
 Protein fibres
 Hooke’s Law
 Conclusion

3. WHAT ISTENSILE PROPERTY?
 Tensile Properties. Tensile properties indicate
how the material will react to
forces being applied in
A tensile test is a fundamental mechanical test
where a carefully prepared specimen is loaded
in a very controlled manner while measuring
the applied load and the elongation of the
specimen over some distance. Titan 10 Universal Testing Machine

4. FACTORS DETERMINING THE RESULTS OF
TENSILE
EXPERIMENTS
The material and its condition
 The behaviour of a material depends on
nature
 Arrangement of the molecules of which it
composed
The arrangement and
dimensions of the specimen
The dimensions of the specimen will, of
course, have a direct effect on the
results of tests. For example, other
things being equal, the breaking load
of a fibre will increase in proportion to
its area of cross-section, and its
elongation will increase in proportion
to its length
The nature and timing of
the test
If a constant load is applied to a
fibre, it will, after its instantaneous
extension, continue to extend for a
considerable time and, if the load is
great enough, it will eventually
break

5. EXPRESSING THE RESULTS
Load–elongation and stress–strain curves
Stress = load/area of cross-section
Specific stress = load/linear density
Tensile strain = elongation/initial
length 000
0
0
Elongation (cm)
2 4
Strain
0.1
Extension (%) 20
Load
(N)
0.06
Specificstress(N/tex)
0.230
0
Stress(MPa)
600 0.4 0.12
10
0.2
Hypothetical load–elongation curve for 20 cm specimen
of 0.3 tex fibre with density of 1.5 g/cm3.

6. WORK OF RUPTURE
Specific work of rupture = work of rupture
/ linear density × initial length
Break
Work of rupture
F
Load
dl Elongation

work done = force  displacement = F· dl
total work done in breaking the fibre = work of rupture
break
= F  dl
0

7. WORK FACTOR
 If the fibre obeyed Hooke’s law, the load–elongation
curve would be a straight line, and the work of rupture
would be given by:
work of rupture = 1/2 (breaking load × breaking
elongation)
 It is convenient to define a quantity, the work factor,
dependent on the difference from this ideal state:
work factor = work of rupture/ breaking load ×
breaking elongation Elongation

8. DIRECT MEASUREMENT OF WORK
OF RUPTURE
work of rupture = loss of potential energy = M g x
Where, M = mass of pendulum and x = difference in height of final positions of pendulum, with
without the specimen.
This method is more rapid than a normal load-elongation test, but the variation of load with time
will depend on the properties of the specimen and the conditions of the experiment.

9. YIELD POINT
Many stress–strain curves have a shape similar to that . After
an initial period with a steep slope, extension suddenly
becomes much easier. It is in this region that the yield point
occurs. In order to locate a precise position, Meredith has
suggested defining the yield point as the point at which the
tangent to the curve is parallel to the line joining the origin to
the breaking point, . This point is then characterised by its
stress and strain as the yield stress and yield strain. Coplan
used a different construction and defined the yield point as
occurring at the stress given by the intersection of the tangent
at the origin with the tangent having the least slope. This is
shown . Alternatively, particularly when there are considerable
linear regions both above and below the yield region, the
point of intersection of the tangents may be taken as the yield
point. Since the stress–strain curve is approximately linear up
to the yield point, the work to the yield point will be almost
equal to 1/2 (yield stress yield strain). Apart from its
indication of the shape of the curve, the yield point is
important because for most materials, elastic recovery, which
is good up to the yield point
Yield
stress
Yield
strain
Strain
Specificstress
Yield
stress
Yield strain Strain

10. EXPERIMENTAL METHODS
The load–elongation curve of a textile fibre
may be obtained by gradually extending it
and measuring the tension corresponding to
each increase in length. The essential
features of any method consist of the jaws
in which the ends of the specimen are held,
the type of specimen used, the method of
varying the load and elongation, and the
means of recording their values to give the
load–elongation curve. Prior to the middle
of the 20th century, a variety of mechanical
testers were used for this purpose and were
followed by early electronic testers
Load
ElongationA O
Load–elongation curve of a crimped fibre

11. OTHER EXPERIMENTAL FEATURES
Some other experimental features that are common to the above
methods may be mentioned here. Single-fibre specimens are best if
it is required to investigate the properties of the fibres themselves,
since the results for bundles of fibres will be affected by the form of
the specimen and the variability of the material, as described in
more detail later . The clamps holding the specimen must not
damage it. If this happens, there will be an undue proportion of
breaks at the jaw. But undue extension or slippage within the jaws
must also be avoided. Care must be taken not to stretch the fibres
during the operations preliminary to the test, since this will change
the fibre properties. An adequate system of sampling must be used,
to take account of the variation in behaviour from one fibre to
another. Moisture- absorbing fibres should be in equilibrium with an
atmosphere of controlled humidity and temperature, which should
always be approached from the same side, preferably the dry side.
x
Ballistic tester
Specimen

12. FIBRE PROPERTIES
Elastic region: In the region from O to A, the fiber
shows elastic region and deformation is called
deformation. At region, Hooke’s Law is obeyed
according to which stress is directly proportional to
strain.
Plastic region: In the region from A to B, the fiber
shows plastic region and deformation is called
plastic deformation. Plastic deformation which
means that it can deform without an increase in the
applied load.
Yield point: The point A is called yield point.
Breaking point: The point B is called breaking
point. The fiber will break at this point.

13. FIBRE PROPERTIES BEHAVIOUR

14. PROTEIN FIBRES
Silk, like nylon, is characterized by fairly high strength and
breaking extension, which combine to give a work of
rupture very much greater than that of the other fibres
tested by Meredith. The wide range of spider silks include
fibres of very highstrength combined with high
extensibility, which leads to very high work of rupture
Wool and other hair fibres are characterised by low
strength but great extensibility. Owing to the high breaking
extension, and to the shape of the curve, the work of
rupture is not low despite the low strength. Different types
of wool give slightly different curves, but these are always
characterised by an initial linear Hookean region up to 2%
extension, a yield region of very low slope from 2 to 30%
extension, and finally a post-yield region of greater slope,
up to a breaking extension around 45%.
50
Load(cN/tex)
5 10 15 20 25
Extension (%)
Stress–strain curves of lyocell (Tencel), modal and
regular viscose rayon compared with cotton.

15. 2
0.15
g/den
0.1
1
0 10 20 30 40 50
2
0
16
12
8
1.8
1.4
1.0
0.6
Tenacity(cN/dtex)
%Breakingextension
N/tex
Amount removed (% initial wt)
Change of tenacity and braking extension of viscose rayon as outer layers
are removed

16. HOOKE’S LAW
Hooke’s Law states that for small
deformities, the stress and strain are
proportional to each other.

17. CONCLUSION
Tensile properties are composed of the reaction of the materials to resist when forces are applied
in tension. Determining the tensile properties is crucial because it provides information about the
modulus of elasticity, elastic limit, elongation, proportional limit, reduction in area, tensile
strength, yield point, yield strength, and other tensile properties.

18. THANK YOU