- Utilization the UTM machine and know the different ways that could test the material’s properties. 2- Knowing the different types of failure in the compression. 3- Determining Young's modulus “E” and Passion’s ratio “υ” and Yield/Proof stress σ y. 1. Finding the impact load effect on the materials. 2. Finding the relative toughness of the different materials. 3. Distinguish between static and dynamic loads and how differently they effect in the material. 4.Knowing the different methods to preform the impact test (Charpy, IZOD, Impact tensile).

1. Spring 2019/2020
FACULTY OF ENGINEERING
MECHANICAL ENGINEERING DEPARTMENT
Strength of Materials LAB
ME 312
[Experiment 3+4]
[Compression and Impact Tests]
Osaid Qasim
Name
24/02/2020
Date

2. Spring 2019/2020
Introduction
Starting in an analogy, we can say that everything in this life
has its opposite case , and applying that in this experiment and
the previous one we could find the same thing ,in the previous
one we talked about the tensile test ,and it was by applying two
axial centric loads in the ends of the specimen , the loads were
opposite and were stretching the specimen, but in this
experiment we talk about applying two opposite axial centric
loads at the ends of specimens trying to compress the specimen .
so, in this experiment we will talk about the "Compression Test”
and it’s define as a capacity of the material to withstand loads
tending to reduce size , and Just as there was an importance in
the “Tensile Test”, the “Compression Test” is very important as
well , and from this test we can obtain a lot of characteristics of
the materials and get a highly important curves from the test’s
data that could be like the ID of the material.
But we’ll discover later that there’s a lot of limitations in this
test comparing with the “Tensile Test”, Therefore when the
experts want to test the materials, they usually use the tension
tests , and we’ll talk about this limitation later in this report.

3. Spring 2019/2020
Objectives
1- Utilization the UTM machine and know the different
ways that could test the material’s properties.
2- Knowing the different types of failure in the compression.
3- Determining Young's modulus “E” and Passion’s ratio
“υ” and Yield/Proof stress σ y.
Test Equipment
“100 KN” UTM
High capacity and old version
machine, and it can test the
compression.
Compression Load Cell
Located in the down part of UTM
and work by the strain gages that
set up by the wheatstone bridge.

4. Spring 2019/2020
Control boxes/Panel (Switch between channels)
Test Specimens
Steel Specimen connected to Cast iron specimens after
strain gauges Compression
Aluminum specimens after Compression

5. Spring 2019/2020
Procedure
1- Add a lubricate to the specimen surface by adding Teflon
sheet to avoid the friction.
2- Fix the specimen in the compression plate that exists under
the cross head and make sure that the specimen has fixed in a
way that a load being axially centric.
3- Attach the strain gauges that we have put in the specimen in
the compression load cell.
4- Strat the UTM and increase the load gradually at speed
2mm/min and read the strain change corresponding that.
Data
: Compression Test (Ductile and Brittle Materials)
1
Part
Material Do [mm] Lo [mm] Df [mm] Lf [mm]
Aluminum 9 11 11.01 6.04
Mild Steel 9 11 11.045 9.53
Cast Iron 9 11 9.05 9.95
Table 1

6. Spring 2019/2020
mple of calculations
Sa
For the Aluminum Data
•
45.091%
-
*100% =
6.04−11
11
* 100% =
𝐿𝑓−𝐿𝑜
𝐿𝑜
=
length
Δ
%
= 22.33%
*100%
11.01−9
9
* 100% =
𝐷𝑓−𝐷𝑜
𝐷𝑜
=
Diameter
Δ
%
Cast Iron
Mild Steel
Aluminum
-9.54 %
-13.36 %
-45.091 %
%Δ length
0.55 %
22.72 %
22.33 %
%Δ Diameter
Table 2
Compression test (specimen with strain gauge)
:
2
Part
Strain gauge readings (m/m)
Load (KN) σ [kPa] Axial strain Lateral strain
0 0 0 0
7.5888 12330.69 0.0000598577 0.0000170595
8.9352 14518.39 0.0000704776 0.0000200861
10.404 16904.98 0.0000820630 0.0000233880
11.8728 19291.56 0.0000936484 0.0000266898
12.4848 20285.97 0.0000984756 0.0000280655
Table 3

7. Spring 2019/2020
calculations
Sample of
2
m
44
615
m) = 0.000
28
*(0.0
𝛑
𝟒
=
𝒅𝒐
𝟐
*
𝛑
𝟒
=
o
A
For the first load:
Pa
12330.69 K
=
𝟕.𝟓𝟖𝟖𝟖
𝟎.𝟎𝟎𝟎𝟎𝟔𝟏𝟓𝟒𝟒
=
𝑳𝒐𝒂𝒅 [𝑲𝑵]
𝑨𝒐[𝒎𝟐]
=
σ
To calculate young’s modulus, we have to find the slope of the stress-
axial strain curve, and to find poisson’s ratio we have to find the slope of
the axial strain-Lateral strain curve, by using curve fitting:
y = 206000007.4x + 6E-05
0
5000
10000
15000
20000
25000
0 0.000020.000040.000060.000080.00010.00012
σ[kpa]
Axial strain (ϵ)
Curve 1 : σ-ϵ diagram
y = 0.285x + 2E-11
0
0.000005
0.00001
0.000015
0.00002
0.000025
0.00003
0 0.00002
0.00004
0.00006
0.000080.00010.00012
Lateral
strain
(ϵ)
Axial strain (ϵ)
Curve 2 : axial strain - Lateral strain

8. Spring 2019/2020
From the curves equations we find that:
E (Young’s Modulus) = 206 GPa
ν (Poisson’s ratio) = 0.285
G (Shear Modulus) =
𝐸
2(1+𝜈)
=
206 𝐺𝑃𝑎
2(1+0.285)
= 80.156 GPa
K (Bulk Modulus) =
𝐸
3(1−2𝜈)
=
206 𝐺𝑃𝑎
3(1−2∗0.285)
= 159.7GPa
Discussion
From (Table 2) we find that in compression the length
difference percent is getting decrease, but the diameter
difference percent is getting increase, and that gave us a hint
about how the failure will be done.
For ductile material (Al), it will failure by barreling and from
the highest diameter that the barreling did, there will be a crack
and then the specimen will fail, and we can see how barreling
will done in (Fig. 1).
And from the same table we find that the length and diameter
for the brittle material (cast iron) doesn’t change significantly
comparing with ductile materials, and that an indication of how
due
o
45
the failure will done in brittle material, and it will fail by
to shear stress.

9. Spring 2019/2020
Comments and observation
• Applying the compression test is not that easy because it has
some limitations and need a very accurate conditions to get my
required data accurate as possible, and these conditions are:
1- Short specimen to avoid buckling (
𝑙
𝑑
equal between 0.8-2)
2- Axial centric load to avoid bending
3- Add a lubricate to the specimen’s surface, usually we use a
sheet of Teflon to avoid friction
• Unlike the tension we found that I the compression test that the
spaces between the material molecules is add a resistance to
compression, but in tensile these spaces are help the specimen to
fail.
• Comparison of the failure between tension and compression
tests for brittle and ductile materials:
Compression
Tension
Material type
because of
o
At 45
shear stress
because of
o
At 90
normal stress
Brittle material
Barreling
because of shear
o
At 45
stress
Ductile material

10. Spring 2019/2020
Part one:
Compression Test

11. Spring 2019/2020
Part two:
Test
Impact

12. Spring 2019/2020
Introduction
In the previous two experiments we used the concept of apply
the loads at the ends of specimens, and the loads was uniform
and change gradually in a low speed (2mm/min), so the time
change is high, but what if the material exposed to a load at very
small interval ?
, and we’ll test it in this experiment
Impact
That what’s called
Impact strength: defined as a capability to resist a sudden
applied load or force, and is expressed as how much the material
)
3
absorbs energy (J) per unit volume (m
And to clarify the concept of impact:
Consider a rod BD with uniform cross section that is hit at end
). As
a
(Fig.1
o
V
moving with a velocity
)
m
(
B by a body of mass
the rod deforms under the impact (Fig. 1b), stresses develop
After vibrating
.
m
σ
within the rod and reach a maximum value
for a while, the rod comes to rest, and all stresses disappear.
Such a sequence of events is called impact loading.
Reference: Mechanics of material book (Beer and Johnston)
impact loading
Fig.1: Rod subject to

13. Spring 2019/2020
Objectives
1. Finding the impact load effect on the materials.
2. Finding the relative toughness of the different materials.
3. Distinguish between static and dynamic loads and how differently they
effect in the material.
4.Knowing the different methods to preform the impact test (Charpy,
IZOD, Impact tensile).
Test equipment
Impact test machine Friction pointer
Start and safety buttons

14. Spring 2019/2020
Striker attached to the hummer Tongs/Holder
. to hit the specimen
Test Specimens
Aluminum and cast
iron specimens after
impact effect
(Charpy test).
Aluminum and cast
iron specimens after
impact effect
test).
IZOD
(

15. Spring 2019/2020
Aluminum and steel
specimens
after impact effect
(Impact tension test).
Procedure
1- Release the impact testing machine from any specimen to
know the friction loss.
2- Put the specimen in the impact testing machine’s vice in a
way that the notch must be apparent, knowing that in IZOD test
it must be like a cantilever beam, but in the Charpy and Impact
tension it be like a simply supported beam.
3- Bring the striker that attached to the hummer (pendulum) up
until it arrives its most high position and lock it there.
4- Bring the indicator to zero, and release the hummer, it will
fall due to the gravity, and the specimen will fail due to the
momentum by the hummer
5- Take the readings from the machine [kg.m] and subtract the
friction loss from it.

16. Spring 2019/2020
Data
Modulus of
toughness
]
3
[KJ/m
Toughness
[Joule]
Machine
reading
[kg.m]
Material
Effective
volume
]
3
[m
Type of
test
42.53
74.8503
7.83
Low Carbon Steel
3
-
1.76x10
Izod
5.66
9.9715
1.215
High Carbon Steel
1.14
2.01105
0.405
Cast iron
13.93
24.525
2.7
Cold work AL
27.53
88.0938
9.18
Low Carbon Steel
3
-
3.2x10
Charpy
4.35
13.9302
1.62
High Carbon Steel
0.63
2.01105
0.405
Cast iron
12.63
40.4172
4.32
Cold work AL
110.52
176.8253
18.225
Cold work Steel
3
-
1.6x10
Impact
tension
71.61
114.5808
11.88
Cold work AL
Table 4
Sample of calculation
For Low carbon steel in Izod test:
Friction loss= 0.2 kg.m
Toughness = (7.83-0.2)*9.81 = 74.8503 Joule
Modulus of toughness =
𝑇𝑜𝑢𝑔ℎ𝑛𝑒𝑠𝑠
𝑒𝑓𝑓𝑒𝑐𝑡𝑖𝑣𝑒 𝑣𝑜𝑙𝑢𝑚𝑒∗1000
=
74.8503
1.76∗10−3∗1000
= 42.53 KJ/m

17. Spring 2019/2020
Discussion
From “Table 4” we can conclude from the material’s data
that the toughness or Modulus of toughness are a good indications
about the material type (Ductile or Brittle), we can observe that
with high value of (toughness/Modulus of toughness) the
material will be a ductile material , but if the value of it was low
, the material will behave like a brittle material .
And we can from this data conclude the strength of a materials,
knowing with high toughness we get high strength , so
comparing between our specimens we find that the Low Carbon
Steel is the toughest one and then the Cold work Aluminum
,High carbon Steel ,and finally the Cast Iron .
Comments and Observations
From the lab we found that in the Impact tension test there is
no data for the Cast Iron , and that because of the special shape
of the test’s specimen that have shown in the report , we can
observe that it is has a toothed ends, and in the Cast Iron it is
seemly impossible to make this teeth.
In our calculations we used just the effective volume because
the deformation will be just at this volume.
And we observe how fast the specimen have failed, unlike the
tension and compression test and that because the sudden load
that the specimen has been exposed.