Fabric Fatigue and Cyclic Loading Testing

Fabric fatigue and cyclic loading testing evaluates the progressive degradation of fabric mechanical properties under repeated stress cycles simulating the loading conditions of seat covers, filter media under pulsating pressure, parachute canopies under repetitive deployment, and geotextiles under traffic loading. Cyclic tensile fatigue (ISO 13934-1 adapted with cyclic extension, fabric extended to 30–80% of static breaking force, held 1 second, returned to 2% extension, cycled 1,000–100,000 times at 0.5–2 Hz, tensile strength measured at intervals — degradation curve plotted): polyester woven seat fabric loses 5% tensile after 50,000 cycles; high-tenacity PP geotextile loses <3% after 10,000 cycles at 30% of ultimate load. Flex abrasion fatigue (ASTM D2097, Scott flexer: fabric creased 180° and abraded simultaneously, cycles to end of service life by visual inspection or 50% strength loss — rainwear PA 1,200 cycles minimum; tent fabric PE laminate 4,000 cycles minimum; tarpaulin PVC 2,000 cycles). Flex crease recovery (ISO 2313, fabric folded under 5 N load 60 seconds, recovery angle measured 30 seconds after release — crease recovery angle CRA% = (recovery angle / 180°) × 100 — specification: easy care cotton shirt fabric CRA ≥ 280° combined warp + weft at standard atmosphere). Fatigue life prediction: S-N curve (stress amplitude versus number of cycles to failure, log-log scale, Basquin equation σ = σ_f(2N)^b) from multiple stress level fatigue tests — enables prediction of geotextile service life at design loading from accelerated test data collected at 50–80% of static breaking strength.