Blade fatigue strength prediction method considering the dynamic effects of ice-propeller interaction

To address the issue of fatigue damage to propeller blades caused by ice impact, this study proposes a global rapid prediction method for blade fatigue strength during the ice-propeller milling process.

A numerical model of ice-propeller milling interaction was established using a PD−FEM coupling algorithm. By integrating a fatigue strength evaluation method based on a modified S−N curve and Miner's linear cumulative damage theory, a reasonable and feasible fatigue strength prediction method was developed for propellers operating under dynamic ice contact loads in ice-covered waters. The algorithm was accelerated using the Python-based parallel computing architecture, enabling the visualization of the three-dimensional fatigue damage contours of the propellers under dynamic ice loading.

It was found that under the milling conditions, fatigue stress on the blade surface was mainly concentrated near the trailing edge at approximately 0.1R, while the fatigue stress on the blade back was mainly concentrated near the leading edge at approximately 0.3R, the mid-chord region of the blade root and the blade tip region. In addition, even at the same position, different blades exhibited varying stress levels and amplitudes due to differences in the magnitude of ice loads, leading to significant differences in the fatigue performance of different blades during ice milling.

The results show that the proposed fatigue strength prediction method can effectively assess the fatigue life of ice-area propellers under complex operating conditions, and provide strong theoretical support for the design and optimization of propellers used in ice-area vessels.