How to test the tear strength value with a tensile machine

The tearing test of the tensile machine is to find the tear strength value. Generally, a tensile machine is used to continuously stretch a rubber product having a cut or a cut without a cut at a prescribed speed until the rubber product is torn, so that a tear strength value can be obtained. The tear strength value is generally related to the shape of the sample, the stretching speed, and the test temperature.

1. Select the pants sample: the pants sample is not sensitive to the length of the slit, while the cutting of the other two samples is strictly controlled. In addition, the results obtained by the tension machine are more likely to be related to the basic tearing ability of the material, but less affected by the tensile stress (generally negligible), and the tear propagation speed is directly related to the tension speed of the holder.

2. Select a straight-angled sample with a cut: a straight-angled sample with a cut is a pre-cut of the sample to determine the force required to expand the tear, but it should be noted that the direction of the tearing machine should be The rolling direction is the same, because the expansion speed is not directly related to the stretching speed, and is related to the cutting method and the rolling direction of the sample.

3. Select a non-cut straight-angle specimen: the non-cut straight-angle specimen is a combination of tear initiation and tear propagation. The stress at the right angle point rises enough to cause an initial tear, and then the stress is further increased until the sample tears. However, only the total force required to destroy the specimen can be determined. Therefore, the force measured by the tension machine cannot be decomposed into two component forces that produce tear initiation and tear propagation.

4. Selecting a crescent-shaped specimen: The crescent-shaped specimen is a pre-cutting of the specimen to determine the force required to expand the tear. The specimen cutting, measurement and test should be carried out continuously, if the test cannot be carried out continuously. The sample shall be stored in the test under the specified temperature test according to the specific conditions. The interval between the cut and the test shall not exceed 24 h, and when the aging test is performed, the cut and the cut shall be performed after aging. The tensile machine should pay attention to the sample. The sample 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.