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8/12/2019 Group d Mech Jimforbes
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Mechanics of Materials-ENGI 23413
LABORATORY REPORT
Title of experiment: Shear Strength
GROUP-D
GroupMembersName
1.Vipanjot Kaur-991311175
2.Simrat Kaur-991312062
3.Taljinder Singh-991306036
4.Gurinder Singh-991308470
PERFORMING DATE: 4 October, 2013
SUBMISION DATE: 11 October, 2013
SUBMITTED TO: James Forbes
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CONTENTS :-
b s t r a c t / E x e c u t i v e S u m m a r y 1
O b j e c t i v e s 2T h e o r y 3
M a t e r i a l s a n d E q u i p m e n t 4
P r o c e d u r e 5
D a t a / O b s e r v a t i o n 6
S a m p l e c a l c u l a t i o n s 7
R e s u l t s 8
D i s c u s s i o n 9
Conclusion&Recommendation 1 0
R e f e r e n c e s 1 1
p p e n d i x 1 2
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The units of shear stress in metric system are
ABSTRACT/EXECUTIVE SUMMARY:-
The purpose of this experiment is to become acquainted with the significance of the shear
strength by performing the shear strength test on the various samples/metals such steel,
aluminium and brass. The diameter measured of samples and the values of different loads
observed from the analog scale and tracer needle helped us to find out the area which further
continued to get the shear strength
Moreover, the observed values of the shear strength were compared to the theoretical values of
shear strength of particular sample/metals .And even the observed and theoretical ultimate
tensile strength values were compared considerably and their relation (ratio) was found
simultaneously.
OBJECTIVE:-
The objective of this lab was to understand the significance of shear strength by performing theshear strength experiments on different materials such as steel, brass and aluminum.
THEORY:-
Shear Stress:-
Shear stress is defined as the forces that act parallel to a given area and in the opposite
direction tending to produce a sliding of one portion past another.It is one of the three basic type
of stress, where compression and tension are other two.
or Pascal (Pa) and in Imperial system Pounds per square
inch which is represented by psi.
Shear Strength and its applications:-
Shear strength is equal to the maximum resisting force divided by the area under the shear:
= F/AShear strength is essential consideration in the designing and performance of many machine parts and
elements. Rivets, bolts and pins are often loaded properly, if not entirely, in the shear. Metalworking
operations such as shear cutting, blanking and punching require forces that are dependent on shear
strength of the material.
.
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fixture:-
Vernier
It have holes inside to putRound Stock double shear
- Caliper:-It
Shear test results are generally less precise than tensile tests because of a small amount of
bending stress and friction is usually present. Shear stress is most common on materials joined
together with rivets, bolts, screws and pins.
Shear tests are often made on flat stock as single or double shear tests. Round stock is most
commonly tested in double shear. For double shear as shown below in picture, the total area of
both cross-sections of the pin must be used in calculating the shear strength.
To calculate the percentage of error,
EQUIPMENT REQUIRED:
VEGA Hydraulic
require the ability
the sample and it
fixture consisting of three plates which are parallel to each other.
is the device used the measure the diameters of
used such as steel, aluminium and brass.
the metal pieces
-
1. Shear:-
Hydraulic shears are used in high volume metal fabricating operations that
to accurately and quickly cut and score sheets of metal.
2. is the
3.
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1 sample each of round stock:
Aluminum
Brass
Cold Rolled Steel
4. -
STAINLESS
NARDfHID
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8.
1.
2.
PROCEDURE:
Each samples diameter was measured and recorded on the observation table.
The sample was inserted into the test fixture so that it would pass through all 3
Plates of double shear fixture.
3. Do not center the specimen in the fixture but let one end project only a shortdistance, so that a second test can be performed on the same specimen.
4. The loaded fixture was then placed in the Vega Shear and the safety door wasclosed.
5. The Vega Shear pressure gauge/analog scale was then zeroed out.
6. A load was applied gradually by hand pumping the hydraulic lever until the
sample sheared.
7. The maximum load was recorded.
After recording the value the shear was loaded a little more so that the shearingslug passed into the relieved area of the lower part of the fixture. Hydraulic
pressure was then released and the fixture removed so the slugs could beremoved.
9. The analog scale and tracer needle were re zeroed and the procedure wasrepeated on the same sample.
10.The procedure again was repeated for the other 2 samples.
-
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distance,
1.
1. Record results in a tabulated form similar to below: lo o o
8. Re-zero
he hydraulic pressure, remove Ihe
7. After failure,
Mechamcs
^f f i t * ~
the
fixture from the machine,
of Materials Lab 2 2
EXPERIMENTAL PROCEDURE:
Measure and record the diameter of each sample
2. Insert a test sample through the hole in all three plates of the double shear fixture
Do No t centre the specimen in the fixture but let one end project only a short
so that a second test can be performed on the same specimen.
3. Place the loaded fixture under the hydraulic press and close the safety guard
4. Check that the analog scale and tracer needle are zeroed
5. Gradually apply load by pumping the hydraulic lever until the sample shears
6. Record the maximum load
continue to press the punch into the holder, so that the shearing
slug passes into the relieved area in the lower part of the holder. Then release
slide the punch
sideways out of the holder and eject the sheared slugs.
dial and make a second test on the same sample
9. Repeat the procedure for the other 2 samples
RESULTS:
X*-L
MATERIAL Maximum Load Average Load | Shear Strengjh
60x5.0
0- \ > O M t v[(A l u m'n k ,
2. Compare results to accepted values
3. Show their relation to tensile strengths
3-
\
Ar t f t
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Steel
Brass
o.\ofc I* *
Diameter
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t
HS-643
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6
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8/12/2019 Group d Mech Jimforbes
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55"
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2.
Aluminum accepted values:
Tensile
RESULTS:-
Our results for Steel Shear = 66 ksi
Steel accepted values:- Shear Strength from 60 ksi
Ultimate Tensile Strength
Our results for Brass Shear = 45.6 ksi
Brass accepted values:- Shear Strength 43 ksi
Ultimate
3. Our results for Aluminum Shear= 31.9 ksi
Ultimate Tensile Strength 55ksi.
DISCUSSIONS:
Therefore, according to our calculations analysis the ultimate shear strength of the 66 ksi and
theoretical value is 60 ksi. We found the percentage error of 9 percent .The ultimate tensile
strength of the steel has the theoretical value of 63.8 ksi. So, the ratio of the ultimate tensile
strength and ultimate shear strength comes out to be 0.96.
Moreover, according to our calculations analysis the ultimate shear strength of the 45.6 ksi and
theoretical value is 43 ksi. We found the percentage error of 4.4 percent .The ultimate tensile
strength of the steel has the theoretical value of 50 ksi. So, the ratio of the ultimate tensile
strength and ultimate shear strength comes out to be 1.09.
Furthermore, according to our calculations analysis the ultimate shear strength of the 31.9 ksi
and theoretical value is 30 ksi. We found the percentage error of 5.9 percent .The ultimate
tensile strength of the steel has the theoretical value of 55 ksi. So, the ratio of the ultimate
tensile strength and ultimate shear strength comes out to be 1.72.
Hence, we observed that the values of the shear strength of aluminium and brass are almost
same as experimental and theoretical. Whereas, in case of steel there is a lot difference
between theoretical and experimental value. Even, percentage error in case of brass is least andin case of steel is more as 9%.
Results, show that shear strength of different materials is different .The ultimate shear strength
value for steel is higher as compared to brass and aluminium. This tells us that steel is very good
and strong metal, whereas, aluminium and brass are less strong. So, in order to cut steel the
large shearing force is required while brass and aluminium can be cut down easily.
Strength 50 ksi.
Strength
1.
63.8 ksi.
- Shear 30 ksi
-
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CONCLUSIONS AND RECOMMENDATIONS
We have noticed that ultimate shear strength is important aspect of material. Our result for the ultimate
shear strength of steel is 6 ksi more than the accepted value ; whereas our results for the brass andaluminum were just slightly higher than the maximum theoretical values. For the brass and aluminum
samples we did not have any information on the material type such as any alloys, heat treatment, cold
working, annealing or tempering. Any of these factors could have affected our shear strength results.
The steel sample we only knew was cold rolled and cold rolled low carbon steel (hard) had a value of 60
ksi shear strength, which is very close to our result of 66 ksi.
While the relation between the theoretical tensile strength and the ultimate shear strength was found in
all the cases it was almost 1 conveniently.
When calculating for tensile strength the force is a pulling force which is divided by the cross-sectional
area. Compared to tensile and compressive stress and strain, the shear forces act over an area which is
in linewith the forces. When calculating the shear strength the force is divided by twice the area since
the shear was at points on the samples. This would explain why the tensile strength is almost double of
the shear strength.
In conclusion our experiment was successful in showing the significance of shear strength. With more
technical information about each sample we may have been able to narrow the range of values for the
shear and ultimate strengths.
The followingrecommendationsare made in order to reduce the errors:-
The analog reader should be replaced by the digital reader to get the accurate readings.
We must know about the physical and mechanical properties of the samples used.
:-
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Bibliography:-
Lab handout
http://en.wikipedia.org/wiki/Ultimate_tensile_strength
http://www.diybanter.com/metalworking/11770-ultimate-shear-strength.
h
t m
l
http://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://www.diybanter.com/metalworking/11770-ultimate-shear-strength.htmlhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strengthhttp://en.wikipedia.org/wiki/Ultimate_tensile_strength