PSI - Issue 57

345 3

Francis Blanc et al. / Procedia Structural Integrity 57 (2024) 343–354 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Verification of the maximum allowable static

Determination of the number of cycles to failure in fatigue • Fatigue tests to failure with several force values • 3 or 4 levels in force • Fratographic examinations of the rupture

Carrying out fatigue tests without failure • Fatigue test with several number of cycles • 3 or 4 levels in duration • Fratographic examinations of the rupture

Determination of the residual static tensile strength • Static tests to failure on the specimes that have been requested by the levels in duration

tensile strength • Static tests to failure

Figure 1: Method for qualifying the fatigue behavior of a rope for a material and for a configuration.

Unlike a wire rope, the tensile strength of a fiber rope decreases significantly after bending fatigue test, depending on the number of repetitive bending. For a given number of cycles, it is then possible to know the reduction of tensile strength, with the tensile strength efficiency. = - : tensile strength efficiency - F maximum : initial tensile strength (before repetitive bending) - F residual : residual tensile strength (after repetitive bending) the winding ratio D / d , the ratio of pulley diameter D to rope diameter d , - the safety factor S f, the ratio of tensile strength to the applied tensile load. The rope's service life can be estimated using the life factorcurves established by testing the rope at different loads and winding ratios. The life factor is determined by the equation: = × with = 3. Test bench and materials 3.1. Static test bench To identify the static characteristics of the rope, we carried out tensile tests on a specific test rig at the rope manufacturer's factory (Figure 2). The aim of these tests was to determine: - tensile strength, - elongation at 50% of tensile strength. The operating conditions that influence rope life are: -