基于断裂力学的破冰船结构疲劳损伤评估方法

In the extremely low-temperature environment of the polar region, with the impact of ice loads, surface cracks within the icebreaker structure exhibit fatigue crack growth characteristics different from that observed in conventional surface ships. Bow structure of the Xuelong 2 icebreaker was applied to illustrate the proposed research approach. Propagation of the fatigue crack at the structural points of the icebreaker is studied based on the fracture mechanics. The propagation method of surface crack is verified based on the theoretical solution of the stress intensity factor at welded joints. Through the global-local coupling analysis, structural sub-models are extracted with respect to typical fatigue points. Crack propagation simulation of the icebreaker is carried out. Effects of initial crack size and low-temperature Paris parameters on the crack propagation of cracked structures in icebreakers are discussed. The results show that the crack propagation behavior at typical structural points of an icebreaker is sensitive to the initial crack size and low-temperature.