Research on damage and cavitation characteristics of propellers under far field shock waves

The propeller is a critical component of a ship’s propulsion system that significantly influences the vessel’s performance through its stability and efficiency. Current research on the propulsion shaft system’s anti-shock properties often oversimplifies the propeller as a uniform circular disk, which disregards its structural intricacies and leads to inaccuracies in the transient damage characteristics during underwater explosions. This research focused on the propeller’s structural details and developed both an equivalent shell model and a more intricate solid model. Through structural wet modal numerical simulations, the study had determined that solid modeling outperforms shell modeling in accuracy. This finding is corroborated by comparisons with empirical formulas, thereby validating the fluid-structure coupling analysis model. Building upon this foundation, the research examines the propeller’s transient shock response and damage characteristics when subjected to far-field shockwaves. Utilizing the total wave algorithm in ABAQUS, the investigation extends to the cavitation and damage patterns of the propeller under such conditions, with confirmation provided by the one-dimensional Bleich-Sandler finite element model. To delve deeper into the phenomenon of hydrodynamic cavitation caused by the propeller’s high-speed rotation, the coupled Eulerian-Lagrangian (CEL) method was applied. Initially, a simplified propeller model was created to confirm the cavitation bubble layer’s fragmentation due to the flow field load resulting from explosive product expansion. Subsequent modifications to the propeller’s transient fluid-structure coupling calculation model allow for a more thorough analysis of its transient damage characteristics. The findings indicate that at attack angles of 0° and 90°, the propeller surface experiences heightened shockwave loads, albeit with a threshold linked to the propeller’s structural properties. When hydrodynamic cavitation is factored in, the stress distribution on the propeller blade tends to be more uniform; the blade’s primary plastic damage is localized at the root, exhibiting both localized and complete plastic deformation patterns. This research elucidates the damage and cavitation effects on propellers due to far-field explosions, offering valuable insights for enhancing the anti-shock defenses of both the propulsion shaft system and the propeller itself.