Tensile specimens made of plastic – specimen shapes
A tensile test can only be as accurate as the tensile specimen allows
In order to achieve correct and reproducible results, the sample geometry must be adhered to exactly. If this is not done, the results can be significantly distorted: the flow behavior changes both the elongation values and the stress values, which are determined as a function of the elongation. In addition, the material properties must not be influenced by the manufacturing process. If the tensile sample is damaged in the measuring length, for example, this can lead to premature sample breakage and the required elongation values are not achieved.
Below you will find a drawing of the tensile specimen and the required dimensions in table form.
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Dimensions of the tensile specimen in mm |
Type 1B |
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Description |
abbreviation |
Measure |
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Whole length a) |
L3 |
> 150 mm |
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length of the narrow parallel part |
L1 |
60 0,5 + mm |
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Radius |
transition radius between head + measuring length |
R |
> 60 mm |
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Thickness b) |
thickness of the flat sample |
h |
2 to 10 mm |
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width of the narrow part |
width of parallel area |
b1 |
10 0,2 + mm |
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width at the ends |
Head width |
b2 |
20 0,2 + mm |
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initial distance between the terminals |
clamping length |
L |
115 1 + mm |
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Measuring length recommended for extensometers |
cutting edge distance Le |
Lo |
50 0,5 + mm |
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a) For some materials it may be necessary to extend the length of the force introduction elements (heads) (e.g. L3 = 200 mm) to prevent breakage (clamp breakage) or sliding in the test clamps (jaws) b) It should be noted that a specimen with a thickness of 4 mm is identical to the type 1B specimen in ISO 527-2 and ISO3167: 1993, Plastics – Multipurpose test specimen. Note: The requirements for quality and parallelism of the test specimen are given in Section 6. |
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