PSI - Issue 57

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

Figure 10: Fatigue curve for 200

For LF200 curve (Figure 10), a complete Lf200 curve has already been plotted with a D/d ratio = 25 (pulley size  300 mm) and an Sf = 8. An additional Lf200 fatigue curve has been partially plotted with a stage point in duration, in order to compare the appearance of different Lf curves with each other. The partial curve was plotted with D/d = 33 (pulley size  400 mm). The comparison shows a certain similarity between the 2 D/d ratios. Fatigue fracture time is shorter on the D/d = 33 curve because the stress is greater (Sf = 6). Comparing the graphs as a percentage of the number of cycles, we note that for the 50% life stage, ratio D/d = 33 has a residual stress at 55% of static failure, compared with ratio D/d = 25 which has around 45% (43% to 55% of the number of cycles), i.e. around 10% more. 6. Fractographic examination For each configuration, we examined the ropes after failure and after a certain number of cycles to study the mode of failure of the rope. All ropes examined show the same type of fusion damage. The greater the effort or the greater the number of cycles and the lower the ratio D/d, the greater the fusion is. Figure 12 illustrates an example of fusion.