1 Scope
This part of GB/T 13772 is intended for the determination of the resistance offered by thread systems of woven fabric, to slippage at a sewn seam.
This method is not suitable for stretch fabrics or for industrial fabrics, e.g. beltings.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) 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—2002, ISO 7500 - 1: 1999, IDT)
GB/T 19022 Measurement management systems—Requirements for measurement processes and measuring equipment ( GB/T 19022—2003, ISO 10012:2003, IDT)
FZ/T 01019 Textile stitch form classification and terminology(FZ/T 01019—1992, eqv ISO 4915:1991)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 constant rate of extension (CRE) testing machine
Tensile testing machine where one clamp is fixed whilst the other is moving with a constant speed throughout the test and where the entire testing system is virtually free from deflection
3.2 grab test
Tensile test in which only the centre part of the specimen is gripped in the jaws
3.3 yarn slippage, seam slippage
Movement, in a woven fabric of weft yarns over warp yarns (or warp yarns over weft yarns) as a result of a pulling action
NOTE: Seam slippage is a fabric property and should not be confused with seam strength.
3.4 warp slippage
Warp yarns slipping over weft yarns, i.e. the warp yarns are at right angles to the direction of pull
3.5 weft slippage
Weft yarns slipping over warp yarns, i.e. the weft yarns are at right angles to the direction of pull
3.6 seam allowance
Distance between the seam line and the adjacent edges of the material
3.7 seam opening
Distance between the yarns which have been displaced on either side of the seam line
4 Principle
An unseamed and a seamed part of a test specimen are separately extended by using a tensile testing machine, fitted with grab test jaws, to produce, in the case of the use of a chart recorder, two force/extension curves originating from the same abscissa. The force required to produce a specified distance between the curves, equivalent to a specified seam opening is determined.
