An accelerated degradation testing method for fatigue life prediction of entangled metallic wire material: Model establishment and validation

This study develops and validates an accelerated degradation testing (ADT) method for predicting the fatigue life of entangled metallic wire material (EMWM), a porous damping material used in aerospace, nuclear, and marine engineering. Constant-displacement-amplitude ADT was performed at 1.0, 1.5, and 2.0 mm under both 25 °C and 300 °C. A convex degradation model and the inverse power law (IPL) were used to fit damage evolution and describe the amplitude-life relationship. Life extrapolation to the normal amplitude (0.5 mm) was validated against conventional tests. Increasing amplitude significantly accelerated degradation. At 25 °C, cycles to reach D = 0.2 dropped from 11.38 × 10⁴ at 1.0 mm to 0.80 × 10⁴ at 2.0 mm; at 300 °C, from 8.11 × 10⁴ to 0.56 × 10⁴. The convex model fit well (R²>0.96) and the IPL model accurately described the relationship (R²>0.98). Predicted normal-amplitude lives deviated from experimental values by 14.1% (25 °C) and 8.43% (300 °C), both within the