PSI - Issue 72

Dražan Kozak et al. / Procedia Structural Integrity 72 (2025) 270 – 277

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Fig. 4. Number of cycles until fatigue failure occurs.

The fatigue sensitivity diagram in Figure 5 shows the minimum number of cycles that the pipe can endure when the load varies between 50% and 150%.

Fig. 5. Fatigue sensitivity diagram.

During operation, approximately 100 tons of stones pass through the canal every hour, which translates to about 1.255 stones falling per second onto the pipe. Analysis results indicate that fractures will occur at the point of impact after 35090 cycles, equivalent to 7 hours and 46 minutes of operation. This calculation assumes that only the largest stones are hitting a single pipe, so the actual number of impacts may be slightly higher. In any case, it would be prudent to consider installing pipes with a larger diameter or made from more durable materials to reduce maintenance costs.