Specimens are cut in a trapezoidal shape with the edge fold position in the center. Then, a 25mm incision is cut along the edge fold. The specimen is pulled apart, until failure, at a constant rate of displacement. The force and displacement are recorded as the tear propagates through the entire edge fold of the specimen, and is used to calculate the resistance to tear propagation of the material.
The challenges of testing to this standard are:
- Specimen gripping
- Reporting calculations in compliance with the standard
- Specimen gripping - In order to mitigate the influence of the grips on the specimen, rubber coated faces are commonly recommended for use with either side acting manual or pneumatic grips.
- Reporting calculations in compliance with the standard - Instron's Bluehill® Universal testing software allows users to input specimen details, set the desired test control, automatically calculate the desired results and statistics, and produce a test report all in accordance with the standard.
It is important to review ISO 11897:1999 in order to fully understand the test setup, procedure, and results requirements.