| Because of the huge potential of the Arctic’s mineral deposits and the unique location of the Arctic,countries have begun to open waterways,transport materials and scientific research in the Arctic.However,the Arctic Ocean is frozen all year round and the ice layer is very thick.Ice breaking has become a technical problem for countries to enter the Arctic.The existing available methods for breaking ice are mainly direct ice breaking methods.Although there are some innovative ice breaking methods,most of them remain at the theoretical stage,and these methods do not involve laser ice breaking.This article mainly focuses on laser spot scanning assisted icebreaking research.The absorption mechanism of 1070 nm wavelength laser by ice has been studied,and the absorption model of the heat source of ice by the laser body has been established.Then,starting from the theory of heat conduction,the finite element method is used to study the temperature field inside the ice block after laser irradiation,combined with the theory of thermoelastic mechanics,the thermal stress field inside the ice block after laser irradiation is solved.Finally,the validity and accuracy of the simulation model are verified by laser single-point irradiation experiments.The influence of the positional relationship between laser power density,focus position and point position on the internal temperature and stress field of the ice block after laser irradiation is studied through simulation,which provides a basis for subsequent simulation and experiments to determine the laser parameters,focus depth and point distribution Reasonable reference.By comparing the stress distribution state inside the ice block before and after the laser assist,the auxiliary effect of the laser in the ice breaking process of surface load and local load is studied,which provides a reasonable basis for the setting of the load value in the subsequent surface load and local load ice breaking experiments.The spot scanning scheme of laser-assisted surface load ice breaking is studied through experiments.First,the experiment of laser single point acting on ice was completed,and the relationship between the hole shape,laser parameters and acting time was established,which provided a basis for determining reasonable laser parameters and acting time for the subsequent scanning scheme.Then,based on the single-point action of the laser,the laser spot scanning plan was preliminarily determined,including the spot layout,movement mode,dwell time,and spot spacing.Finally,in order to improve the auxiliary effect of the laser in load-breaking ice,factors such as the distance between points,the scanning order of points and the number of points were adjusted,and the preliminary determined scanning scheme was optimized.The spot scanning scheme of laser-assisted local load ice breaking is studied through experiments.Through orthogonal experiments of three factors and three levels,the influence of window size,number of points on one side and laser irradiation time on the ice breaking effect was studied,and a more reasonable laser spot scanning scheme was determined for local load ice breaking. |
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