1
KEEE1110 Material Science Lab Report
Name: SHARIDYA RAHMAN (KEE130704)
Name of Demonstrator: Miss Chia
Tensile Testing
Objective:
1. To find the following information from mild steel, Aluminum Alloy, Acrylonitrile
Butadiene Styrene (ABS) and polyethylene (PE).
Engineering tensile stress
Strain
Yield stress
Ultimate tensile stress
Percent elongation, %EL
Percent reduction in area, %AR
2. To investigate and compare the mechanical properties between mild steel and Al alloy
and between PE and ABS and understand the properties of these materials.
Abstract:
The mechanical properties of a material are directly related to the response of the material
when it's subjected to mechanical stresses. Since characteristic phenomena or behavior occur
at discrete engineering stress and strain levels, the basic mechanical properties of a material
are found by determining the stresses and corresponding strains for various critical
occurrences. A wealth of information about a material's mechanical behavior can be
determined by conducting a simple tensile test, for instance modulus of elasticity, yield
strength, ductility and toughness. It is important and significant that these features are known
and scrutinized to predict the loads at which failure might occur and prevent any occurrence.
In this experiment strength of materials is evaluated experimentally for four separate
specimens using advanced and modern testing equipment. Other mechanical properties are
also determined by calculation from the readings and material behavior is investigated and
understood from all prospects
In tensile experiment, the materials to be tested is managed into a shape that can be gripped
in the testing machine, and pulled at a constant rate until it breaks. In the pulling process of
the specimens, changes occur in its physical dimensions and its mechanical properties. The
testing machine elongates the specimen at a constant rate and continuously measures and
records the applied force and elongation of the specimen. Consequently it also produces a
graph to illustrate material behavior.
,2
Introduction:
A Universal Testing Machine is commonly used in performing the tensile test. General
techniques utilized for measuring loads and displacements employs sensors providing
electrical signals. Load cells are used for measuring the load applied while strain gauges are
used for strain measurement. A Change in a linear dimension is proportional to the change in
electrical voltage of the strain gauge attached on to the specimen.
Test is done on specimen having uniform cross section area. So for metals round specimens
are used with adequate thickness that can be gripped properly and easily by the machine. For
plastics flat specimens are employed. Standard dimension of these specimens are known
which include gauge length and cross sectional area perpendicular to the direction of
application of force.
The test is carried out by applying longitudinal force along the axis of the specimen at
constant rate. Due to increment in tensile load the specimen will break at one point when
tensile limit has extended. The result is then recorded in a computer controlled package in the
form of load versus displacement or force versus elongation graph. Extensometer attached to
the Universal Testing Machine is used to record elongation and tensile modulus. Hence this
incredible machine provides us useful features and characteristics like tensile strength, elastic
limit etc. The datas collected from the experiment is used to determine mechanical properties
as illustrated below:
𝐹
i.) Engineering stress,𝜎 = 𝐴
𝐿1 −𝐿0
ii.) Strain, 𝜀 = 𝐿0
load at yield
iii.) Tensile Strength at Yield, 𝜎𝑦 =
cross sectional area
load at max
iv.) Tensile Strength at Maximum, 𝜎𝑚 =
cross sectional area
L1 −L0
v.) Elongation and percentage elongation = × 100%
L0
A1 −A0
vi.) Reduction and percentage reduction in area = × 100%
A0
Where
F = strength (N)
A0 = original cross-sectional area (mm2)
A1 = instantaneous cross-sectional area (mm2)
L0 = original gauge length (mm)
L1 = instantaneous gauge length (mm)
, 3
Mild steel or plain carbon steel has carbon content of 0.15-0.3%. It is tougher and more
elastic than wrought iron. It is ductile and malleable. Hence, it can be forged and welded, but
still it cannot be tempered and hardened easily. Its hardness can be increased by carburizing.
Due to its low cost it employed in industries quite often for multifarious purpose. Its
limitation includes poor impact resistance at low temperatures and poor corrosion resistance
leading to engineering problems. It is also readily oxidised at elevated temperature. Thus, the
characteristics of this metal allow it to be used in the form of rolled sections and reinforcing
bars.
Aluminium has a unique combination of attractive properties. Low weight, high strength,
superior malleability, easy machining, excellent corrosion resistance and good thermal and
electrical conductivity are amongst aluminium’s most important properties. Aluminium is
also very easy to recycle. Unlike most steel grades, aluminium does not become brittle at low
temperatures. Instead, its strength increases. At high temperatures, aluminium’s strength
decreases.Aluminium is capable of being a superconductor, with a superconducting critical
temperature of 1.2 Kelvin and a critical magnetic field of about 100 gauss.
Polyethylene is a polymer consisting of long chains of the monomer ethylene which contains
the chemical elements carbon and hydrogen. It can be produced through radical
polymerization, anionic addition polymerization, ion coordination polymerization or cationic
addition polymerization. Polyethylenes are semi-crystalline materials with excellent
chemical resistance, good fatigue and wear resistance, and a wide range of properties (due to
differences in length of the polymer chain.). Polyethylenes provide good resistance to organic
solvents, degreasing agents and electrolytic attack. They have a higher impact strength They
are light in weight, resistant to staining, and have low moisture absorption rates Polyethylene
is classified into several categories based on its density and branching, such as low density
polyethylene (LDPE) and high density polyethylene (HDPE).
Acrylonitrile butadiene styrene (ABS) is a copolymer of Acrylonitrile, Butadiene, and
Styrene. ABS plastics generally possess medium strength and performance and medium cost.
ABS possesses outstanding impact strength and high mechanical strength, which makes it so
suitable for tough consumer products. Additionally, ABS has good dimensional stability and
electrical insulating properties.
KEEE1110 Material Science Lab Report
Name: SHARIDYA RAHMAN (KEE130704)
Name of Demonstrator: Miss Chia
Tensile Testing
Objective:
1. To find the following information from mild steel, Aluminum Alloy, Acrylonitrile
Butadiene Styrene (ABS) and polyethylene (PE).
Engineering tensile stress
Strain
Yield stress
Ultimate tensile stress
Percent elongation, %EL
Percent reduction in area, %AR
2. To investigate and compare the mechanical properties between mild steel and Al alloy
and between PE and ABS and understand the properties of these materials.
Abstract:
The mechanical properties of a material are directly related to the response of the material
when it's subjected to mechanical stresses. Since characteristic phenomena or behavior occur
at discrete engineering stress and strain levels, the basic mechanical properties of a material
are found by determining the stresses and corresponding strains for various critical
occurrences. A wealth of information about a material's mechanical behavior can be
determined by conducting a simple tensile test, for instance modulus of elasticity, yield
strength, ductility and toughness. It is important and significant that these features are known
and scrutinized to predict the loads at which failure might occur and prevent any occurrence.
In this experiment strength of materials is evaluated experimentally for four separate
specimens using advanced and modern testing equipment. Other mechanical properties are
also determined by calculation from the readings and material behavior is investigated and
understood from all prospects
In tensile experiment, the materials to be tested is managed into a shape that can be gripped
in the testing machine, and pulled at a constant rate until it breaks. In the pulling process of
the specimens, changes occur in its physical dimensions and its mechanical properties. The
testing machine elongates the specimen at a constant rate and continuously measures and
records the applied force and elongation of the specimen. Consequently it also produces a
graph to illustrate material behavior.
,2
Introduction:
A Universal Testing Machine is commonly used in performing the tensile test. General
techniques utilized for measuring loads and displacements employs sensors providing
electrical signals. Load cells are used for measuring the load applied while strain gauges are
used for strain measurement. A Change in a linear dimension is proportional to the change in
electrical voltage of the strain gauge attached on to the specimen.
Test is done on specimen having uniform cross section area. So for metals round specimens
are used with adequate thickness that can be gripped properly and easily by the machine. For
plastics flat specimens are employed. Standard dimension of these specimens are known
which include gauge length and cross sectional area perpendicular to the direction of
application of force.
The test is carried out by applying longitudinal force along the axis of the specimen at
constant rate. Due to increment in tensile load the specimen will break at one point when
tensile limit has extended. The result is then recorded in a computer controlled package in the
form of load versus displacement or force versus elongation graph. Extensometer attached to
the Universal Testing Machine is used to record elongation and tensile modulus. Hence this
incredible machine provides us useful features and characteristics like tensile strength, elastic
limit etc. The datas collected from the experiment is used to determine mechanical properties
as illustrated below:
𝐹
i.) Engineering stress,𝜎 = 𝐴
𝐿1 −𝐿0
ii.) Strain, 𝜀 = 𝐿0
load at yield
iii.) Tensile Strength at Yield, 𝜎𝑦 =
cross sectional area
load at max
iv.) Tensile Strength at Maximum, 𝜎𝑚 =
cross sectional area
L1 −L0
v.) Elongation and percentage elongation = × 100%
L0
A1 −A0
vi.) Reduction and percentage reduction in area = × 100%
A0
Where
F = strength (N)
A0 = original cross-sectional area (mm2)
A1 = instantaneous cross-sectional area (mm2)
L0 = original gauge length (mm)
L1 = instantaneous gauge length (mm)
, 3
Mild steel or plain carbon steel has carbon content of 0.15-0.3%. It is tougher and more
elastic than wrought iron. It is ductile and malleable. Hence, it can be forged and welded, but
still it cannot be tempered and hardened easily. Its hardness can be increased by carburizing.
Due to its low cost it employed in industries quite often for multifarious purpose. Its
limitation includes poor impact resistance at low temperatures and poor corrosion resistance
leading to engineering problems. It is also readily oxidised at elevated temperature. Thus, the
characteristics of this metal allow it to be used in the form of rolled sections and reinforcing
bars.
Aluminium has a unique combination of attractive properties. Low weight, high strength,
superior malleability, easy machining, excellent corrosion resistance and good thermal and
electrical conductivity are amongst aluminium’s most important properties. Aluminium is
also very easy to recycle. Unlike most steel grades, aluminium does not become brittle at low
temperatures. Instead, its strength increases. At high temperatures, aluminium’s strength
decreases.Aluminium is capable of being a superconductor, with a superconducting critical
temperature of 1.2 Kelvin and a critical magnetic field of about 100 gauss.
Polyethylene is a polymer consisting of long chains of the monomer ethylene which contains
the chemical elements carbon and hydrogen. It can be produced through radical
polymerization, anionic addition polymerization, ion coordination polymerization or cationic
addition polymerization. Polyethylenes are semi-crystalline materials with excellent
chemical resistance, good fatigue and wear resistance, and a wide range of properties (due to
differences in length of the polymer chain.). Polyethylenes provide good resistance to organic
solvents, degreasing agents and electrolytic attack. They have a higher impact strength They
are light in weight, resistant to staining, and have low moisture absorption rates Polyethylene
is classified into several categories based on its density and branching, such as low density
polyethylene (LDPE) and high density polyethylene (HDPE).
Acrylonitrile butadiene styrene (ABS) is a copolymer of Acrylonitrile, Butadiene, and
Styrene. ABS plastics generally possess medium strength and performance and medium cost.
ABS possesses outstanding impact strength and high mechanical strength, which makes it so
suitable for tough consumer products. Additionally, ABS has good dimensional stability and
electrical insulating properties.
