1 Scope
This part of GB/T 3917 describes a double-tear method known as the tongue test, using a test specimen with cuts shaped to form a tongue. The tear force measured is the force required to propagate the previously started double tears when the force is applied parallel to the cuts and the fabric tears in the direction of the applied force.
The test is mainly applicable to woven textile fabrics. It may be applicable to fabrics produced by other techniques, e.g. to some nonwovens.
In general the method is not applicable to knitted fabrics and woven elastic fabrics.
The method only allows the use of constant-rate-of-extension (CRE) testing machines.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this part of GB/T 3917. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, the parties to agreements based on this part are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 6529 Textiles — Standard atmospheres for conditioning and testing (GB/T 6529-2008, ISO 139:2005, MOD)
GB/T 16825.1 Verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Verification and calibration of the force-measuring system (GB/T 16825.1-2008, ISO 7500-1: 2004, IDT)
GB/T 19022 Measurement management systems — Requirements for measurement processes and measuring equipment (GB/T 19022-2003, ISO 10012: 2003, IDT)
3 Terms and Definitions
For the purposes of this part of GB/T 3917, the following terms and definitions apply.
3.1 Constant-rate-of-extension (CRE) testing machine
Tensile-testing machine where one clamp is stationary whilst the other is moving with a constant speed throughout the test.
