This test measures the tensile strength, ultimate elongation, yield point, modulus of elasticity of a plastic using a micro dogbone specimen per test method ASTM D638. Read more here: www.admet.com/testing-applica...
Testing the Tensile Properties of Plastics and Elastomers
Summary of Test
ASTM D638 is one of the most common plastic strength specifications and covers the tensile properties of unreinforced and reinforced plastics. This test method uses standard “dogbone” shaped specimens under 14mm of thickness. A universal testing machine (tensile testing machine) is needed to perform this test. If you are going to perform this test, you should read the entire specification from ASTM.
CLICK TO CONTACT US
Or call us at (800) 667-3220
Test Procedure
To perform ASTM D638, begin by injection molding your material into a “dogbone” sample. Load the sample into a pair of tensile grips and attach your extensometer (if you have one). The speed at which you separate your tensile grips depends on the shape of the specimen and can range from 0.05-20 inches per minute. End the test at sample break (rupture).
Calculations:
Tensile Strength
Elongation at Yield
Elongation at Break
Nominal Strain at Break (Grip Separation)
Modulus of Elasticity
Secant Modulus
Poisson’s Ratio (Requires Transverse Extensometer)
Equipment Required for ASTM D638
A Universal Testing Machine with the following specifications:
Servo-control to ensure constant rate of speed during the test
Capacity needs to be enough for your materials. Depending on your material’s ultimate tensile strength, you may use a machine with 1,000, 2,000, 5,000, or 10,000 lbf of capacity
ADMET Recommends: eXpert 2600 Dual Column Testing Machine, eXpert 7600 Single Column Testing Machine
An extensometer should be used especially when measuring modulus and yield
ADMET Recommends: Extensometers
Software or suitable electronics are required to operate the machine and to take the measurements
Basic systems will provide the raw data and stress-strain charts. Using these data, you can determine and calculate all of the analyses listed above. Fully PC-based systems have the capability to calculate all of these automatically. ADMET offers both
ADMET Recommends: MTESTQuattro PC-based Controller
Tensile grips hold your specimen during the test as it is being pulled apart
Any grip with serrated faces is usually adequate for this test. You can use wedge, pneumatic, vise, or other self tightening grips
ADMET Recommends: Vise Tensile Grips, Wedge Grips, Pneumatic Grips
22 апр 2012
