Tear test of various samples by electronic universal testing machine

The tearing experiment of the electronic universal tester is to obtain the tearing strength value. The electronic universal tester uses the electronic universal tester to continuously stretch the rubber products with or without cutting mouths at a specified speed until the rubber pattern is torn off, so that the tearing strength value can be obtained. The tear strength value is generally related to the sample shape, tensile speed, and test temperature.

1. Choose a right-angle sample without cut mouth: a right-angle sample without cut mouth is a combination of tear start and tear spread. The stress at right angles rises enough to occur for initial tear, and then the stress increases further until the sample tear. However, the total force required to destroy the sample can only be determined. Therefore, the measured force cannot be decomposed into two component forces that produce tear onset and tear spread.

2. The electronic universal testing machine uses crescent samples: crescent samples are used to cut the sample in advance to measure the force required for its expansion and tearing. The sample cut, measurement and test should be carried out continuously. If the test cannot be carried out continuously, the sample should be stored at the specified temperature test to the test according to the specific situation. The interval between the cutting and test should not exceed 24 hours. When performing aging test, the cutting and cutting should be carried out after aging. When making samples, the electronic universal testing machine should pay attention to that the samples should be cut from the test piece with uniform thickness. The thickness of the test piece is (2.0±0.2) mm. The test piece can be molded or cut and polished by the product.

3. Choose pants-shaped samples: Use pants-shaped samples to be insensitive to the length of the incision, while the cutting openings of the other two samples require strict control. In addition, the results obtained are more likely to be related to the basic tearing ability of the material, which is less affected by the fixed extension stress (usually neglected), and the tear expansion speed is directly related to the tension speed of the clamp.

4. The electronic universal test machine uses a right-angle sample with a cut-out: a right-angle sample with a cut-out is to pre-cut the sample to measure the force required for its expansion tearing. However, it should be noted that the direction of the tearing cutting port should be consistent with the calendering direction, because the expansion speed has no direct relationship with the tensile speed, and is related to the cutting method and calendering direction of the sample.