How to conduct tensile tests on plastics
一、Testing process of the tensile testing machine:
Usually, in product standards, only the cracking strength is specified, while the cracking elongation is not required. If the cracking elongation is not required, then the operator does not need to consider the relevant details.
1.During the test, use fixtures to clamp the sample to ensure that the sample is in the same direction as the applied force. Do not touch any part of the useful length (the section between the two fixtures) of the sample with bare hands. When the fixtures are clamped, the sample should be straightened.
2. If the tensile testing machine has the ability to apply pre-tension, then a pre-tension of (5 ± 2.5) mN/tex should be applied to the sample. This pre-tension is calculated based on the nominal linear density of the yarn. However, if this pre-tension causes the sample to elongate by more than 0.5%, then this method is not applicable. In case of any disputes, the test should be conducted on a testing machine with the required pre-tension capability.
3. Rotate the moving fixture at a speed of 200mm/min. After the specimen cracks, record the cracking strength and the elongation under that cracking strength. Return the moving fixture to its zero position and remove the cracked specimen's broken end.
4. The test results of samples that slipped in the jaws, cracked within the jaws, or cracked within 10mm of the jaw edge will be disregarded. If the number of samples disregarded exceeds 10% of the total tested samples, the fixture should be re-adjusted. In case of necessity, non-direct fixtures (such as winch type or other methods) should be used. In this situation, the elongation values obtained are not comparable to those from direct fixtures. Result presentation.
二、Testing steps for the tensile testing machine:
1.Usually, in product specifications, only the breaking strength is specified, while the breaking elongation is not required. If the breaking elongation is not required, the operator does not need to consider the relevant details.
During the test, use fixtures to clamp the sample to ensure that the sample is in the same direction as the applied force. Do not touch any part of the effective length (the section between the two fixtures) of the sample with your bare hands. When the fixtures are clamped, the sample should be straightened.
2. If the tensile testing machine has the ability to apply pre-tension, then a pre-tension of (5 ± 2.5) mN/tex should be applied to the sample. This pre-tension is calculated based on the nominal linear density of the yarn. However, if this pre-tension causes the sample to elongate by more than 0.5%, then this method is not applicable. In case of any dispute, the test should be conducted on a testing machine that has the required pre-tension capability.
3. Run the moving fixture at a speed of 200mm/min. After the specimen breaks, record the breaking strength and the elongation at that strength. Return the moving fixture to its zero position and remove the broken specimen end.
4. The test results of the samples that slipped in the jaws, broke within the jaws, or broke within 10mm of the jaws will be discarded. If the number of discarded samples exceeds 10% of the total number of tested samples, the fixture should be re-adjusted. In case of necessity, a non-direct type fixture (such as a winch type or other forms) should be used. In this situation, the measured elongation value is not comparable to that of the direct type fixture.
