Yarn Tensile Testing — Strength and Elongation
topic
Yarn tensile testing measures breaking force (cN), tenacity (cN/tex), elongation at break (%), and work of rupture (cN·cm) using a constant rate of extension (CRE) tester at 500 mm gauge length, 500 mm/min test speed (ISO 2062). Minimum 20 tests per sample for statistical reliability. CVT% (coefficient of variation of tenacity) should be <8% for weaving quality. Single-thread strength testing is complementary to bundle strength (Pressley, Stelometer) for fibre quality assessment.
Role
Tensile testing is the contractual quality gate for warp yarn supply. Warp yarn must meet minimum tenacity and maximum CVT% specifications — typically >12 cN/tex and CVT%<8% — to survive the mechanical stress of the weaving shed without excessive warp breakages. Every warp yarn lot is tested, and non-conforming lots are either re-classified as weft or rejected, making tensile testing a direct financial risk management tool.