Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Investigation on ice-breaking resistance of a ship bow advancing in level ice
Xuhao Gang1, Yukui Tian*1, Shaopeng Ji1, Peter Jochmann2, Chaoge Yu1, Ying Kou1
1.China Ship Scientific Research Center, Wuxi, Jiangsu, P. R. China
2.POLAR-CONSULT, Borstel-Hohenraden, Germany

component is including the friction when ice floes are sliding along thehull (Lindqvist, 1989). By observing the process of ice breaking, the total
resistance acting on the ship hull can be further subdivided into thefollowing categories: breaking, rotary, submersion, and sliding force(Valanto P, 2001). In order to investigate the mechanism of ice resistancein depth, experimental and numerical means are indispensable. Modeltests in level ice and pre-sawn ice were carried out in the ice basin of
Korea Institute of Marine Engineering (KRISO), and the empiricalformula of non-dimensional coefficients were obtained (Jeong,etc.,2010). The ship type and traffic profile have a large influence on iceresistance. The effect of bow shapes on ice-breaking process was studied
at HSVA, by Daniela Myland. She found a correlation between bow
shape parameters, the total resistance and breaking pattern. Based on her
analysis she refined the Lindqvist formula. (Daniela Myland, etc.,2016).
There are also several numerical simulation methods used to calculate
the process of ship-ice interaction. Wang idealized the ice-breaking
process as a cycle of contact-bending failure, and proposes a numericalmethod in the time domain (Wang, 2001). Biao Su divided the ice
breaking process into two parts: icebreaking force and the ice forcesinduced in the displacing progress and established a three-degree-offreedom coupling equation between the ice load and the ship motion,
which was in good agreement with the experimental data ofAHTS/IB(Biao Su, 2011). The discrete element method has uniqueadvantages due to the transformation from continuum to discretesegment during the interaction between ice and structure (Ji,2018). Lau
simulated the nonlinear large deformation and fracture process in theinteraction between flat ice and cone type structures, and wrote the threedimensional discrete element program DEMICE 3D (Lau et al., 2011).
Ji introduced GPU-based high-performance computing methods into
discrete element numerical simulation, which significantly improved thecalculation scale and efficiency of DEM method, and applied it to theresearch of icebreakers (Ji et al., 2016).
An effective ice navigation prediction method needs to a clear
understanding of the generation mechanism and internal components ofthe physical quantities under studied. So a research project was carriedout at CSSRC ice tank. The model tests were carried out with asegmented model, that allowed the determination of different ice
resistance components, in the CSSRC’s Small Ice Model Basin. The
results of the model tests are presented, discussed, and compared with
empirical formula. The establishment of a combined procedure canprovide a solid and powerful technical means for engineering
applications such as navigation performance and design optimization for
ice-going ship.

ABSTRACT
Accurate prediction of the continuous icebreaking process in level ice iscrucial for the design of ice-going ships. Physical simulations areperformed as ice model tests in ice test basins, it is one of the mostprecise simulation methods. The model tests were carried out in theSmall Ice Model Basin (SIMB) of CSSRC with a model divided into
different segments. To research the resistance characteristics and its
composition, a quasi-two-dimensional bow model based on the WaasBow concept was designed. Tests were performed in level ice and presawn ice sheets. The total ice resistance of the bow was measured by a6-component scale, while the forces acting on each segment weredetermined by 3-component load cells. This test setup allowed
determination and comparison of the ice resistance components. The ice
breaking and clearing process was observed and documented byunderwater video cameras placed on the basin bottom and used for shipice interaction analysis. Based on the model tests, the influences
advancing velocity during the continuous icebreaking process weredetermined, the composition of ice resistance is analyzed, and the ice
failure modes and ice floe motions are studied.

KEY WORDS: icebreaking ships; icebreaking resistance; ship
bow; model test
INTRODUCTION
When assessing the performance of ships operating in the ice, the totalresistance in ice, Rit is the most important criterion for the icebreaking
ability. The in-depth study of the ice resistance is most important for thehull design and optimization of ice-going vessels. It will determine thepower to be installed and, together with the propeller-ice-interaction, thespeed and thus the icebreaking capability of the vessels.
When navigating in an almost uniform ice cover or giant floes a vessel
breaks the ice predominantly by bending but crushing at the stem and theshoulder could also be involved. In the further course of the process, theice floes are turned, submerged and slide all along the ship hull. Ideally,
the ice floes are pushed under the surrounding ice cover by the shape ofthe ship's hull. One of the main contributions of the total ice resistancein level ice is the breaking resistance (Puntigliano, 2003), it can accountfor more than 40% of the total resistance. In a first attempt the total ice
resistance was divided into two main components, breaking of the ice
sheet and submersion of the ice floe. The breaking component includes
the resistance due to crushing and bending, and the submersion

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