Tensile Properties - ASTM D638
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Tensile testing is performed by elongating a specimen and measuring the load carried by the specimen.
From a knowledge of the specimen dimensions, the load and deflection data can be translated into a stress-strain curve. A variety of tensile properties can be extracted from the stress-strain curve.
Tensile Test
| Property |
Definition |
| Tensile Elongation at Break |
Tensile elongation corresponding to the point of rupture. |
| Tensile Elongation at Yield |
Tensile elongation corresponding to the yield (an increase in strain does not result in an increase in stress). |
| Tensile Strength at Break |
Tensile stress corresponding to the point of rupture. |
| Tensile Strength at Yield |
Tensile stress corresponding to the yield point (an increase in strain does not result in an increase in stress). |
| Tensile Strength |
Tensile stress at a specified elongation. |
| Tensile Strength, Ultimate |
The highest tensile stress a material can support before failing. |
| Tensile Modulus |
The ratio of tensile stress to tensile strain of a material in the elastic region of a stress-strain curve. A "Tangent" tensile modulus value is the slope of the elastic region of the stress-strain curve and is also known as Young's Modulus, or the Modulus of Elasticity. A "Secant" tensile modulus value is the slope of a line connecting the point of zero strain to a point on the stress-strain curve at a specified strain. This is used for materials that exhibit little or no linear behavior. |
Illustration of Tangent and Secant Tensile Moduli
Test Specimen Summary
| Specimen |
Rigidity Case |
Note |
Thickness |
| Type I |
Rigid |
Preferred specimen. |
<7 mm (0.28 in) |
| Type II |
Rigid |
Use when Type I specimen does not break in the narrow section. |
<7 mm (0.28 in) |
| Type III |
Rigid/Nonrigid |
|
>7 mm (0.28 in)
<14 mm (0.55 in) |
| Type IV |
Rigid/Nonrigid |
Should be used for comparison between materials in different rigidity cases. Essentially the same as Die C specimen from ASTM D412. |
<4 mm (0.16 in) |
| Type V |
Rigid |
Used when limited material is available or laboratory space is a concern (for environmental testing) |
<4 mm (0.16 in) |
Type I, II, III, and V Specimen
Type IV Specimen
Similar Standards
Property information for specific grades of resin are available in the Prospector.
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