- Estimation methods, Principles and
Factors affecting the values.
One of the fundamental methods in
Sample is subjected to controlled
tension until failure.
Results are used for the selection of materials for various
purposes considering how it will react under different types of
Properties measured – UTS (Ultimate Tensile Strength),
Maximum elongation, Reduction in area.
From these properties following properties can be determined:
Young’s Modulus, Poisson’s Ratio, Yield strength
Uniaxial tensile testing – Isotropic materials
Biaxial tensile testing – Composite materials
What is Tensile Testing
Tensile testing is a way of determining how something will
react when it is pulled apart - when a force is applied to it
Tensile testing is one of the simplest and most widely used
mechanical tests. By measuring the force required to
elongate a specimen to breaking point, material properties
can be determined that will allow designers and quality
managers to predict how materials and products will behave
in their intended applications.
Along the tensile profile there are many points of interest,
chief among them the elastic limit and force to break or
Standard Polymer Tensile Testing Methods
D638 - Test Method for Tensile Properties of Plastics.
D5083 - Fiber-reinforced thermosetting laminates.
D882 - Thin Plastic Sheeting.
D1922 - Tearing resistance of various plastic films and thin
sheeting by Pendulum method.
D412 - Vulcanized Rubber and Thermoplastic Elastomers.
D3039/D3039M - Polymer Matrix Composite Materials.
Types Of Tensile Testing
Crimp joint pull-off force
Advantages Of Tensile Testing
Tensile testing provides data on the integrity and safety of
materials, components and products, helping manufacturers
ensure that their finished products are fit-for-purpose and
manufactured to the highest quality.
The data produced in a tensile test can be used in
many ways including:
To determine batch quality
To determine consistency in manufacture
To aid in the design process
To reduce material costs and achieve lean manufacturing goals
To ensure compliance with international and industry standards
Step 1: Original shape and size
of the specimen with no load.
Step 2: Specimen undergoing
Step 3: Point of maximum
load and ultimate tensile
Step 4: The onset of necking
Step 5: Specimen fractures.
Step 6: Final length.
Cut or injection mold your material into “dog bone” shape under 14mm
Load the specimen into tensile grips.
Begin the test by separating the tensile grips at a constant rate of speed.
Speed can range from 0.05 – 20 inches per minute.
The target time from start of test to break should be from 30 seconds to 5
End the test after sample break (rupture)
Thin Plastic Film less then 1mm in thickness
Load your sample into your grips.
Enter your specimen geometry (width,
thickness, and gage length) into your
Speed : 20inch/min
Sample is a 63mm x 76mm rectangle
The energy loss by the pendulum is used
to calculate an average tearing force.
Test results are presented as tearing
force in milli-newtons.
Tearing force lies in the range of
0-800 gram force.
Sample thickness is also reported.
Only results for samples of the
same thickness can be compared.
Specimens are placed in the grips of a Universal Test
Machine at a specified grip separation and pulled until
For ASTM D5083 the test speed may be determined
by the material specification.
The default test speed is 5 mm/min.
Depending upon the reinforcement and type, testing in
more than one orientation may be necessary.
The standard specimen has a constant rectangular
cross section, 25 mm wide and at least 250 mm long.
Thickness can be between 2 mm (0.079 in) and 14
Factors Influencing Tensile Strength
The effect of additives and impurities
Geometric size and shape
Orientation and Morphology
Energy and speed of loading
The environment- Humidity.
Strains in the article due to external loads
Jaw Slippage, deformation due to jaw pressure
higher strain at the neck of the specimen
contribute to the error.
Stress-strain graphs of two plastics
(a) A rigid polymer at a temperature below Tg- High tensile strength but less area under sress
(b) An amorphous polymer greater than Tg –low tensile strength but more area under stress
Tensile strength increases with
Effect Of Temperature:
• The Effect of Temperature and other Factors on Plastics and Elastomers
-By Laurence W. McKeen
• Effect of temperature on tensile properties of injection moulded short
glass fibre and glass bead filled ABS hybrids
• Fundamentals of Material Science and Engineering
• ASTM website