0 exp no.4 bending test experiment

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Faculty of Engineering Petroleum
Engineering Department
Mechanics of Material Laboratory, 2nd stage
Experiment Name: Bending test experiment
Prepared by: Muhammed Fuad Rashid
Ahmad Jalal Hassan
Muhammad Hassan Aziz
Safwan Tofiq Ameen
Group: A
Supervised by: Dr.Diyar

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Contents
1.Introduction.............................................................................................................................3
2. Aim of the test ........................................................................................................................5
3. Methodology...........................................................................................................................6
3.1. Sample preparation..........................................................................................................6
3.2. test machine.....................................................................................................................7
3.3. Test proceeding................................................................................................................8
4.Results and discussion............................................................................................................10
4.1. data obtained (from the graph) ......................................................................................12
4.2. Data obtained (from calculations)...................................................................................14
4.3. Discussion.......................................................................................................................15
6.References:............................................................................................................................17

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1.Introduction
Bend testing, sometimes called flexure testing or transverse beam
testing, measures the behavior of materials subjected to simple
beam loading. It is commonly performed on relatively flexible
materials such as polymers, wood, and composites. At its most
basic level a bend test is performed by placing a specimen on two
support anvils, which is bent through applied force on 1 or 2 loading
anvils. The force is applied with either a single upper anvil at the
midpoint, which is a 3-point bend test, or two upper anvils
equidistant from the center, a 4-point bend test.
In a 3-point test the area of uniform stress is quite small and
concentrated under the center loading point. In a 4-point test, the
area of uniform stress exists between the inner span loading points
(typically half the length of the outer span). Depending on the type
of material being tested, there are many different flex fixtures that
may be appropriate.

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2. Aim of the test
Engineers often want to understand various aspects of material’s
behavior, but a simple uniaxial tension or compression test may not
provide all necessary information. As the specimen bends or flexes,
it is subjected to a complex combination of forces including
tension, compression, and shear. For this reason, bend testing is
commonly used to evaluate the reaction of materials to realistic
loading situations. Flexural test data can be particularly useful
when a material is to be used as a support structure. For example,
a plastic chair needs to give support in many directions. While the
legs are in compression when in use, the seat will need to
withstand flexural forces applied from the person seated. Not only
do manufacturers want to provide a product that can hold
expected loads, the material also needs to return to its original
shape if any bending occurs. Precisely we can say the objective is ;
1. To study and examine the flexural properties of materials.
2. To investigate how the dimension and shape of materials affect
the flexural.
3. To develop an understanding about the flexural properties of
materials

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3. Methodology
3.1. Sample preparation
Bend tests are generally performed on a universal testing
machine using a 3 or 4 point bend fixture. Variables like test speed
and specimen dimensions are determined by the ASTM or ISO
standard being used. Specimens are generally rigid and can be
made of various materials such as plastic, metal, wood, and
ceramics. The most common shapes are rectangular bars and
cylindrical-shaped specimens.
To perform a bending test a specimen of the material is
made into a “standard” shape as it mentioned above.., The sample
preparation of a bending test is just like a tensile test but it differs
from the tensile test from some things for example in bending test
the gage-length of the sample should be subtracted from its end
which is out of the two roller supports that supports the specimen
because the load acts on the load which is between the two
supports till the edge of the supports , thus to obtain the right
values . then we should measure the cross-sectional area of the
sample that means we measure the width and thickness of the
specimen, also the length is necessary and needs to be measured
for the calculations.
our specimen was a steel and had both side cross sectional of
rectangular shape. And the specimen’s composition was(steel) and
its dimension’s is right below, so finally The sample was already
machined to the proper dimensions required for the bending test
experiment, according to ASTM standards.

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3.2. test machine
A machine is used in bending test experiments to perform the
experiment and our labs machine for bending test have the
specifications and its description below;
Model No. 5982
System ID /SN 5982L33117
Configuration E1-F1-G1
capacity 100KN(2500Ib)
weight 784kg(1732Ib)
Date of manufacture March,21,2012
voltage 220 Volts
frequency 47-63 Hz
Maximum power 3500 VA
Circuit breaker 20Amp
Short circuit current

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3.3. Test proceeding
First of all after that our specimen was prepared which its
mentioned how prepared in preparation of sample section with its
specification of its dimensions, now the first should be done The
Blue Hill data acquisition software was started and in the final
proceeding of the software’s procedure The load cell acts on the
specimen was zeroed to ensure that the software only measures
the right data that will be obtained from the specimen after that
we sat our specimen on the two supports of the machine which
were both roller supports but with a little distance away from the
edges of the specimen which must be equal from both sides
because the material was longer the place of the two roller
supports (supports the specimen only in one direction) and this was
all done so as to obtain the right values and properties of the
sample, also prevent damage to the machine.
After the sample was connected to the machine the blue hill
software was set to the right options for the specimen’s property
and proceeding the software to prepare for the test but there’s
some need to be mentioned for example, the strain ratio (defined
at definition section) ;
Strain ratio=2mm/minute
And its very important to set the strain ration in a small ratio to
ensure the accurate results and not directly rapture the specimen
.if not then our curve will not give the whole details about the test.
Then, the test was started, and the specimen was load Applied
from the cell, resulting in a measureable readings of the specimen
according to the software after that the load was applied we waited
nearly for 8 minutes and till the sample was fractured and got to
rapture ,what we observed meanwhile was the sample was going

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to bending position and the sample got to bend(like curve) after a
moments later ,as the axial load increases on the sample finally the
sample at a specific load got to fracture in its bellow part of the
specimen , and that was the final steps of proceeding the
experiment.

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4.Results and discussion
After the test was produced ,the data was gathered from the
software and obtained the right values on a graph(software’s
proceeding) ,from the graph of the bending stress and strain
diagram,
Figure 1stress strain bending diagram
According to the figure number 1 .we can determine lot of the
specimen’s properties which is the aim of our experiment which
are to determine the following properties of the specimen;
 maximum stress
 yield strength
-50
0
50
100
150
200
250
1 226 451 676 901 11261351157618012026225124762701292631513376360138264051
flexurestress(MPA)
flexure strain(mm)
stress starin bending diagram
Series1
Series2

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 modulus of elasticity(young’s modulus)

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4.1. data obtained (from the graph)
1-maximum stress; which is the maximum value of stress acted on
the specimen which located on the top or pick of the stress strain
diagram .
Maximum stress= 213.018𝑀𝑃𝑎
2-yield strength; this property of the material can be determined
as the point comes after the elastic limit which means the material
can no longer back to its original shape from the stress strain
diagram .
Yield strength= 182.273𝑀𝑃𝑎
4-modulds of elasticity; the modulus of the specimen can be
obtained from the stress strain diagram by taking the average of
the slopes of the points are in proportional limit from the curve.
First modules of elasticity= 48.89105𝐺𝑃𝑎
Second modules of elasticity= 48.50245𝐺𝑃𝑎
Third modules of elasticity= 48.66540𝐺𝑃𝑎
Average youngs modules=(48.89105 + 48.50245 + 48.66540)/3
= 48.68630𝐺𝑃𝑎
5-Maximum load; can be defined as the maximum load which
applied ay the load cell to the specimen

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Maximum load = 90.038𝐾𝑃𝑎
6-Maximum extension= 54.259𝑚𝑚

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4.2. Data obtained (from calculations)
Maximum stress which we determined it from graph(which was
the top of the curve )
Maximum stress(by calculating)=
3𝑓𝑙
2𝑏𝑑2
𝑙=170𝑚𝑚
𝑏=34𝑚𝑚
𝑑=1.75𝑚𝑚
𝑓(from plot)=91𝑁
𝜎𝑓 = 222.857𝑀𝑃𝑎

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4.3. Discussion
So as we can see the results are determining the behavior of the
material as it should be to a specimen like steel, the maximum
stress and the young’s modulus determine for us that steels is very
powerful material also has large amount of ductility as result it
resists a larger amount of bending stress than a for example a wood
does , for example they used in making wings of plains because
they bend with out to fracture ,.our specimen in lab nearly it didn’t
fractured at all which means the steel has a good property of
bending that bends at a large distance with out fracturing ,also the
material made of plastic or rubber have also large amount of
flexibility .

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5.0. Conclusion
And finally the aim of the experiment was successfully done which was to
determine a number of the specimen properties such as maximum stress and
young’s modulus an so on The system functions by using metal bending bars
of varying thickness and stiffness to deform the test specimen. The force
applied is measured by use of a built-in calibration and calculation system , a
data was gathered from performing the experiments which helped us in
many ways to determine the materials properties and to benefits from in our
life in manufacturing of equipments and tools and many more to be used in
our life , so finally I would say bending experiments helps us to understand
more about material and to benefit from them in many ways.

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6.References:
 Instron.us. (2019). What is Bend Testing? - Instron. [online] Available
at: https://www.instron.us/our-company/library/test-types/flexure-
test [Accessed 12 Dec. 2019].
 Gilbert, J. A and C. L. Carmen. "Chapter 8 –Flexure Test." MAE/CE 370
–Mechanics of Materials Laboratory Manual. June 2000
 Dowling, N.E., Mechanical behaviour of materials: Engineering
methods for deformation, fracture and fatigue, 2nd edition, 1999,
Prentice Hall,ISBN-0-13-010989-4.
 Hibbleler,R.C., Mechanics of Materials, SI second edition, 2005,
Prentice Hall, ISBN
0-13-186-638-9

0 exp no.4 bending test experiment

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0 exp no.4 bending test experiment