Investigation On Ice-breaking Resistance Under Continuous Ice-breaking Mode With Bow Of Ice-going Ship

Ice resistance prediction has always been a hot topic in the research on navigation performance of ice-going ships,and it is related to the key issues such as assessment of ice breaking capability,design and optimization of hull form,as well as power instal ation and propulsion system configuration.However,the domestic research on ice resistance is still in its preliminary stage,there are many core technologies need to be broken through in both ice basin model testing and numerical simulation.In this paper,the ice breaking resistance of bow under continuous ice breaking mode is focused to make such investigations physically and numerically that establish relavent prediction methods for technical support to the ice resistance optimization,design and evaluation of ice-going ships.Firstly,the experimental research of ice-breaking resistance in ice basin is carried out with a typical bow model.The type of ship bow model is designed with reference to Waas bow,and tests in level ice,pre-sawn ice and open water are performed respectively.The total ice resistance of the ship bow and the ice resistance of each separate block are measured at the same time,and the relationship between total ice resistance and ice resistance from the blocks are analyzed.And then the effect of speed on ice breaking resistance is analyzed.Water surface and underwater videoing techniques are adopted to capture the ice fracture mode and motion trajectory,which can be used to trace the periodic process of continuous ice breaking on the bow and analyze the interaction mechanism between bow and ice.Secondly,based on the distinct element method,a numerical simulation method for icebreaking resistance on the bow is developed.The cellular array is introduced to develop force transfer model,the Euler angle method is applied to analyze the unit motion and then establish the numerical simulation model,which is programmed as Bri-DEM code with MATALAB.Ice breaking with a two-dimensional inclined plate is numerical y simulated to examine the simulation model,and the influence of different ice unit forms is investigated.Then,with using the model ice parameters from the ice mechanics testing and inputting the three-dimensional ship bow numerical calculation model,the ice breaking resistance of the ship bow model is calculated.By comparing the results from the numerical calculation and those from model tests,the reliability of the numerical model is verified.Finally,two typical influencing factors of icebreaking resistance,bow angle and ice thickness,are selected to perform numerical calculation with the validated Bri-DEM code.The outputs are used to predict and analyze the ice resistance for multiple schemes,and the effects of bow angle and ice thickness variations on icebreaking resistance are obtained.In general,a fundamental research on the ice breaking resistance under continuous ice breaking mode with bow of ice-going ship is carried out by means of the combination of physical modeling and numerical simulation in the small ice model basin(SIMB)of China Ship Scientific Research Center(CSSRC).The research results wil provide benificial support to ice resistance prediction,navigation performance evaluation as wel as hull form design and optimization for ice-going ships.