Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Mechanical Testing: Uniaxial Tension Test
Introduction
A uniaxial tensile testing machine is a very common machine used to perform tensile tests on selected
specimens to determine the mechanical properties of materials that are important in design. A
specimen is placed into grippers on the machine and the specimen is deformed, usually to fracture, with
a gradually increasing tensile load that is applied uniaxially along the long axis of the specimen. The
machine is designed to elongate the specimen at a constant rate and to simultaneously measure the
instantaneous load and elongation. A load vs. elongation is then produced on a computer and from
there engineering stress and strain and true stress and strain can be calculated.
Objective
The objective of this lab is to determine the respective properties of an Aluminum 6061(round)
specimen, AISI 1020 Steel(round) specimen, Gray Cast Iron(round) specimen, and an AISI 1020
Steel(sheet metal) specimen by conducting a uniaxial tension test. From the load vs. elongation data
generated by the machine we are to make four graphs of each specimen: Load vs. Elongation,
Engineering Stress vs. Engineering Strain, True Stress vs. True Strain, and True Stress vs. True Strain on a
log log plot. From these graphs we will be able to determine/learn the mechanical properties of each
specimen.
Procedure
Apparatus:
Universal Testing Machine
Caliper
Measuring Scale
Micrometer
Gage Length Punch
Materials and Specimens:
Aluminum 6061-round specimen
AISI 1020 Steel-round specimen
Gray Cast Iron-round specimen
AISI 1020 Stell-sheet metal specimen
1. Using a caliper, measure the width and thickness (or diameter for round specimens) at several
locations along the shaft of each specimen to determine the average cross-sectional dimensions.
Record the average measured width and thickness of each specimen on the data sheet.
2. Place the specimen in the grips. Make sure that each end is firmly attached to the grips.
3. Punch the gage length on the shaft of the specimens using the gage length punch.
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
4. Measure the length of the specimen between the punch marks. This is the gage length and will be
used to calculate strain.
5. Adjust the caliper for a length slightly larger than the gage length and record that length.
6. Adjust the micrometer for a slightly smaller diameter than the original diameter of the shaft and
record that diameter.
7. Begin applying the tensile load to the specimen and observe the live reading of applied load on the
digital display. The read-out displays the applied tensile load in Newton or lbf.
8. Continue applying tensile load slowly, observing the shape of the sample closely. Check frequently
until sample reaches the adjusted length on caliper and record the corresponding load. Repeat step
5.
9. Repeat step 8 until specimen diameter starts to change. Check for change in diameter frequently
using the micrometer.
10. Check the diameter and the length of the specimen until they reach the adjusted values on the
caliper and micrometer, record the corresponding load values. Repeat steps 5 and 6.
11. Load the specimen until failure and repeat step 10 until failure. Record the maximum load and the
load at failure.
12. Remove the broken specimen from the machine. Observe the location and character of the
fracture.
13. Measure the width and thickness of each specimen in the region of failure and record final
measurements.
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Results
1020 Steel Round (Load vs. Elongation)
100
90
80
70
Load (kN)
60
50
1020 Steel Round (Load vs.
Elongation)
40
30
20
10
0
0
1
2
3
Elongation (mm)
4
5
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Eng. Stress (kN) vs. Eng. Strain (1020 Steel
Round)
0.8000
0.7000
0.6000
Eng. Stress
0.5000
0.4000
Eng. Stress (kN)
0.3000
0.2000
0.1000
0.0000
0.0000 0.0100 0.0200 0.0300 0.0400 0.0500 0.0600 0.0700 0.0800 0.0900
Eng. Strain
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
True Stress(kN) Vs. True Strain(1020 Steel Round)
1.0000
0.9000
0.8000
0.7000
Stress
0.6000
0.5000
True Stress(Mpa) Vs. True
Strain
0.4000
0.3000
0.2000
0.1000
0.0000
0.0000
0.1000
0.2000
0.3000
Strain
0.4000
0.5000
0.6000
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Log Log True Stress Vs. True Stress(AISI Steel
Round)
1.0000
y = 0.361x + 0.7492
Log Log True Stress Vs. True
Stress
Linear (Log Log True Stress Vs.
True Stress)
0.1000
0.1000
1.0000
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Load Vs Elongation for Aluminum 6061
12000
10000
8000
6000
Load Vs Elongation
4000
2000
0.28
0.275
0.27
0.26
0.25
0.24
0.2
0.1
0.15
0.05
0.04
0.01
0.0075
0.00875
0.00625
0.005
0.00375
0.0025
0.00125
0
0
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Engineering Stress Vs Engineering Strain of
Aluminum 6061
60000
50000
40000
30000
Engineering Stress Vs
Engineering Strain of Aluminum
6061
20000
10000
0
0.000625
0.00125
0.001875
0.0025
0.003125
0.00375
0.004375
0.005
0.02
0.025
0.05
0.075
0.1
0.12
0.125
0.13
0.135
0.1375
0.14
0
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
True Stress Vs True Strain of Aluminum 6061
100000
90000
80000
70000
60000
50000
True Stress Vs True Strain of
Aluminum 6061
40000
30000
20000
10000
0
0.000625
0.00125
0.00187
0.0025
0.00312
0.00374
0.00437
0.00499
0.0198
0.0247
0.0488
0.0723
0.0953
0.1133
0.4463
0.5489
0.6022
0.7133
0.7713
0
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
True Stress Vs True Strain Log Log of Aluminum
6061
100,000.00
y = 3978.5x + 57282
10,000.00
True Stress Vs True Strain Log
Log of Aluminum 6061
1,000.00
Linear (True Stress Vs True
Strain Log Log of Aluminum
6061)
100.00
10.00
1.00
0.0723 0.0953 0.1133 0.4463 0.5489 0.6022 0.7133 0.7713
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Load vs. Length (sheet metal)
12000
10000
8000
6000
load (lbs) vs length
4000
2000
0
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
load (lbs) vs width (sheet metal)
load (lbs) vs width
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
7657
9402
9959
10220
10340
10377
10368
10314
10152
9671
8592
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Computer Generated Graph of `1020 Steel Sheet Metal
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Raw Data of 1020 Sheet Metal
Load(lbf)
7657
9402
9959
10220
10340
10377
10368
10314
10152
9671
8592
8500
Properties
Width(in.)
0.652
0.650
0.630
0.615
0.609
0.597
0.594
0.581
0.577
0.516
0.495
0.456
Max Thickness=0.257 in
Elongation(in.)
2.063
2.125
2.188
2.25
2.313
2.375
2.438
2.5
2.563
2.625
2.688
2.75
Aluminum 1020 Steel
Gray
1020 Steel Sheet
6061 rod rod
Cast Iron Metal
Tensile Test Raw Data
12.7 mm
0.5 in
N/A
Initial Diameter, D0 0.5 in.
2 in.
50.8 mm
2 in
2”
Gage Length, L0
Tensile Test Results
9,750 lbf
82 kN
NA
10,377lbs
Yield Load, Py
2.15 in.
51.1 mm
NA
N/A
Yield Length, Ly
90 kN
7853.9 lbf
10,382lbs
Maximum Load, Pu 9,900 lbf
2.24 in.
52.3 mm
2 in
2.375”
Length at
maximum load, Lu
7,800 lbf
70 kN
7853.9 lbf
8500lbs
Fracture Load, Pf
54.8 mm
2 in
2.75”
Fracture Length, Lf 2.28 in.
2
2
0.1963 in.
126.67 mm
0.196 in^2
0.16882
Initial Area, A0
9,750 psi
0.6473 kN/mm2 40000 psi
10,382lbs
Yield Strength, Sy
2
85,910.63 psi 0.7105 kN/mm 40000 psi
N/A
Ultimate Tensile
Strength, SUTS
N/A
Young’s Modulus, 69 GP6 a or 10 320.82 kN/mm2 NA
X 10 psi
E
0.09079 in2
74.66 mm2
0.196 in^2
0.1171
Final Area, AF
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
% Area Reduction,
% Ar
% Elongation, % El
Strain Hardening
Coefficient, K
Strain Hardening
Exponent, n
53.76 %
41.06%
NA
69.37%
14 %
7.87%
NA
N/A
4.98
5.61 kN
NA
N/A
74,210.43
.361
NA
N/A
Sample Calculations of 1020 Steel Rod:
 Young’s Modulus (E) is found by finding the slope of the elastic part of the Eng. Stress vs. Eng.
Strain curve, which the equation if the line is found to be: y=320.86x-0.6315. Thus, the slope of
the elastic part is 320.86, which in turn is our Young’s Modulus (E) of 320.86 kN/mm2.

% 𝐴𝑟𝑒𝑎 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 =

% 𝐸𝑙𝑜𝑛𝑔𝑎𝑡𝑖𝑜𝑛 =

𝑙𝑓 −𝑙𝑜
𝑙𝑜
𝐴𝑜 −𝐴𝑓
𝐴0
126.67𝑚𝑚2 −74.66𝑚𝑚2
∗ 100
126.67𝑚𝑚2
54.8𝑚𝑚−50.8𝑚𝑚
∗ 100 = 7.87%
50.8𝑚𝑚
∗ 100 =
∗ 100 =
= 41.06%
The strain hardening coefficient(K) and exponent(n) can be found from the log log graph of true
stress vs. true strain, where n is the slope and K is the Y-intercept.
o When we find to equation of our line on the log log graph we get y=.361x+0.7492. This
equation is in the logarithmic for so it what is really saying is the y=log(σ), n=.361,
x=log(ϵ), and b=log(K).
o Since n is just the slope it is easy to determine.
o Since K is the Y-intercept, b, we must solve for K in 𝑏 = 0.7492 = log(𝐾).
 0.7492 = log(𝐾) => 100.7492 = 𝐾, thus K=5.61
 K is given in force so K=5.61 kN.
Discussion
When comparing the collected data provided for the aluminum 6061 rod to the data collected
for the AISI 1020 steel rod in the lab, the first thing we noticed was the tensile load at which
both materials experienced fracture. For the AISI 1020 sheet metal specimen that we observed
in lab, the specimen material fractured at 8,592 lbf whereas, according to the data provided,
the aluminum 6061 rod fractured at 7,800 lbf respectively. We also noticed the initial diameter
of both the aforementioned materials was somewhat close to one another (0.5 in. for the
aluminum 6061 rod; 0.652 in. for the AISI 1020 sheet metal,) and their final respective
diameters were also somewhat close to one another as well (0.34 in. for the aluminum rod;
0.495 in. for the AISI 1020 sheet metal.) Also, the elongations of the both the materials were
somewhat close to one another as well, which leads me to conclude that the materials
properties of the aluminum 6061 rod and the AISI 1020 steel sheet metal are somewhat similar
to one another. When comparing cast iron to the aluminum rod they seem to have to same area but
the aluminum has more elasticity so it stretched more before it fractured. Even though the aluminum
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
had a much higher maximum load the cast iron had a higher fracture load. The length stayed the same
with the cast iron but it changed in the aluminum because of its elasticity. Most of the properties
between aluminum and the steel rod seem to be similar they are not exactly the same but they are
much closer than those the properties of grey cast iron. When comparing the 1020 steel rod to the
aluminum we see that the steel rod had a much higher yield load, fracture load, and maximum load
compared to aluminum. Although the 1020 steel rod had a shorter elongation compared to the
aluminum rod, this is due to the fact that the steel rod is less ductile than aluminum. When comparing
the graphs of the 1020 steel rod to the aluminum rod we see that the aluminum rod had a much more
gradual slope of its elastic zone compared to the 1020 steel rod, once again confirming that the
aluminum rod is more ductile. The true stress vs. true strain graph of the aluminum rod is a more linear
representation than compared the true stress vs. true strain of the 1020 steel rod. From the properties
found in each metal the 1020 steel rod had the highest max load, yield load, and fracture load. This
means that the steel rod is very strong material.
Conclusion
In conclusion, from this lab, We learned how to conduct a tensile test of a material by using a
uniaxial tensile testing machine, as well as how to manually measure both the change in gauge
length of the material specimen (with a caliper,) and the change in diameter of the material
(with a micrometer.) We also learned how to create a load vs. elongation graph from the load
and elongation data collected and provided for this lab; a engineering stress vs. engineering
stain graph using by calculating both the engineering stress and engineering strain of the
material by using the collected data and given measurements per material; a true stress vs. true
strain graph by calculating both the true stress and true strain of the material by using the
collected data and the given measurements per material; and lastly, a true stress vs. true strain
log log plot by using the yield point to fracture point on the true stress vs. true strain graph.
Drew Williams
Dylan Terry
Travis Watts
Devin Gatherwright
IET 307 Lab #1
Prof. Madhavannair
Contributions




Drew Williams
o I made the graphs for the 1020 Steel Rod specimen and found its properties. I
also put the lab report together from the group’s data. 25%
Travis Watts
o Calculations for gray cast iron specimen and helped with the discussion and
conclusion of the lab report. 25%
Devin Gatherwright
o Contributed calculations of properties and graphs for the Aluminum 1020 rod
and also contributed to the discussion and conclusion sections of the lab report.
25%
Dylan Terry
o 1020 steel sheet metal. Only Load vs. Elongation graph. Was not able to finish
other graphs and property calculaitons 10%