Mechanism analysis of propeller-ice contact and rapid prediction of ice loads

Abstract

To facilitate the rapid prediction of propeller ice loads, as well as to aid in the assessment of strength and optimal design of ice-class propellers, a state-based peridynamic (PD) method was utilized for mechanism analysis of propeller-ice contact and ice-loads sensitivity analysis. Both critical bond-stretch (CS) and critical energy (CE) damage criteria were implemented to determine whether sea ice is damaged. A verification example and comparison were given for a milling test. The design space for the propeller section was evaluated to perform the sensitivity analysis of ice loads to airfoil geometry and milling angle of attack. Based on the sensitivity results, a rapid-prediction method for propeller ice loads was proposed. As the airfoil mills ice with a slight angle (smaller than 7°), the CE criterion is more suitable than the stretch criterion. It was found that, by sensitivity analysis, there is little difference in the magnitude of ice loads applied on different airfoils with varying camber and thickness distribution and maximum thickness. Only the change in the maximum camber will make a difference in the transversal ice load. A propeller ice-loads calculation example shows the feasibility and convenience of the proposed prediction method, the error of which is only 4.5% compared with the experimental value.