PSI - Issue 57

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

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4. Parameters

4.1. Test bench parameters

The test bench detects rope failure when a sudden and significant displacement of the hydraulic cylinder occurs. The bench then stops immediately by stopping rotating and releasing the tension. The bench also stops if the temperature increases over 90°C, which has been proved to be well-suited to detect the cable's end-of-life. In both cases, once the test bench has been stopped, the test may be restart to ensure that the cable has reached its end of life. The rope then only holds a few cycles. We changed the 2 basic parameters which are the pulley diameter and the applied load. This allows to study the sensitivity of the D/d ratio and of the safety factor . Table 1 shows the values used. Table 1. Test parameters Life factor ( ) Pulley diameter ( ) [mm] Ratio / Safety factor ( ) 75 150 12.5 6.0 75 300 25.0 3.0 100 150 12.5 8.0 100 300 25.0 4.0 100 400 33.3 3.0 150 300 25.0 6.0 150 400 33.3 4.5 200 300 25.0 8.0 200 400 33.3 6.0 4.2. Tests parameters

5. Results

5.1. Fatigue strength

The BASQUIN curve plots the number of bending cycles to failure versus the applied force. Figure 5 presents curves for different / ratios: - BASQUIN model mean curves for 50% failure rate (solid line) - Probabilized curves for 10% probability of failure (dashed line) with a confidence level of 0.75. The D/d = 25 curve (in black) serves as a reference. The D/d = 33 curve is shifted to the right, indicating that this ratio provides a greater number of cycles for the same safety coefficient. The D/d = 12.5 curve is shifted sharply to the left, indicating that this ratio does not allow a high number of cycles for the same safety coefficient.