Lab Report Tensile Strength

Lab Report - Tensile Strength

Date : 24-Feb-2013

Experimental Data
Cold Work Steel (CWS) – Specimen 1

Width (mm)
Thickness (mm)

I
II
III
Average
I
II
III
Average
Before
10.029
10.04
10.02
10.0297
3.06
3.07
3.07
3.0667
After
9.09
9.00
-
9.045
2.60
2.40
-
2.50

Annealed Steel (As) – Specimen 2

Width (mm)
Thickness (mm)

I
II
III
Average
I
II
III
Average
Before
10.24
10.13
10.10
10.16
3.07
3.08
3.09
3.08
After
8.11
8.08
-
8.095
2.32
2.34
-
2.33

Polyethylene (PE) – Specimen 3

Width (mm)
Thickness (mm)

I
II
III
Average
I
II
III
Average
Before
10.12
10.11
10.15
10.127
3.29
3.31
3.27
3.29
After*

* = no measurement required

Log Sheet
1. Plot the stress-strain curves for all of the specimens tested (2 graphs should be presented. One should consist of the stress-strain curve for the polymer, the other should consist all three curves)

Graph of all three curves :

Graph of the polymer curve (PE) :

2. Determine the following mechanical properties from the stress-strain curve for each of the specimens (by graphical method), and summarize these properties in a table. Sample calculation is to be included in the Appendix.
Young’s Modulus
0.2% yield strength
Yield strength
Tensile strength
Ductility
Fracture stress
Toughness
Properties
CWS
AS
Polyethylene
Young’s Modulus (MPa)
22,304.15
19,269.34
786.90
0.2% Yield Strength (MPa)
895
565
16
Yield Strength (MPa)
815
540
15.5
Tensile Strength (MPa)
923.44
852.73
29.46
Ductility (%)
26.48
39.73
-
Fracture Stress (MPa)
749.22
710.35
17.75
Toughness (MJ/m3)
59.61
95.4
11.82

3. Compare, contrast and discuss the mechanical properties of these specimens.
The CWS specimen is the specimen that has been through a cold-work process. Cold Work is a process to strengthening the