This standard specifies a procedure to determine the tear force of nonwoven textile fabrics using the trapezoid method. A rectangular specimen is marked and prepared so that it can be loaded in the grip faces at an angle, allowing a tear to propagate across the specimen.
For this test, it is important to have an increased test data rate to ensure the capture a high number of data points. This is because when individual fibers within the fabric fail, the data rate must be fast enough to catch these peaks.
Pneumatic side action grips with rubber coated jaw faces are well suited for clamping of the trapezoid specimens. While manual action grips will work, many prefer pneumatic side action grips for ease of use, productivity, and better repeatability. Adjustable grip pressure also allows users to fine-tune the gripping pressure to avoid jaw breaks or slippage.
The challenges of testing to this standard are:
- Rapid data capture rate
- Specimen gripping
- Rapid data capture rate with Instron's 5900 controller allows data peaks and valleys to be captured accurately at up to 2,500 points per second
- Instron pneumatic side action grips with rubber faces are well-suited to gripping nearly all types of fabric specimens for this test while maintaining high throughput
It is important to review ISO 9073-4:1997 in order to fully understand the test setup, procedure, and results requirements.