Author(s): Wang Wei-Hao; Zeng Jia; Xu Yi-Gang; Zhang Wei; Wang Yan-Wu; Wu Gang
Linked Author(s):
Keywords: High-ice-class vessels; Plastic design philosophy; Nonlinear analysis criteria; Optimized design scheme
Abstract: Based on the IACS Polar Class Rules, elastic-range strength assessments are relatively reasonable and feasible for medium and low ice-class vessels (PC3 and below). However, for high ice-class vessels subjected to sharply increased ice loads, adhering to linear design criteria imposes excessive penalties in terms of space and weight. Nonlinear structural assessments of the ice belt reveal significant strength margins in conventionally linearly designed structures. By adopting plastic design philosophy that accounts for the load-carrying capacity in the post-yield plastic phase, the dimensions of the ice belt structures can be significantly reduced, thereby saving internal hull space and reducing structural weight. This paper takes the midship structure of a heavy-duty icebreaker as the research object and performs optimization of the ice belt structure based on the nonlinear direct strength calculation criteria provided in the CCS “Guidelines for Direct Strength Calculation under Ice Loads.” Based on the optimization results, the study extends the rational applicability of the current regulatory framework for nonlinear assessment and proposes a novel ice belt structural optimization design from the perspective of energy absorption through structural deformation. The findings provide a valuable reference for plastic design of ice belts in high ice-class ships.
Year: 2026