Damage due to start-stop cycles of turbine runners under high-cycle fatigue

This study presents a strategy to estimate the extra cost due to start-up and shut-down of hydro turbines under high-cycle fatigue. The principle is to compare estimations of cumulated damages from three elementary sequences representing steady and transient regimes (start and stop cycles) of turbine runners, from in-situ strain measurements. Rainflow cycle-counting is used to extract stress cycles from these three sequences. Fatigue design...