| With the development of new wave and utilization of abundant mineral energy resources in polar regions in recent years,research on the safety and reliability of the construction of basic equipment for polar scientific research(polar ships and polar offshore platforms)has become a main concern in the field of ship and ocean engineering.The ice formed under the severe weather conditions in the polar regions is one of the biggest threats to the operation of polar scientific research equipment in cold waters.The occurrence of ship ice collision accidents and equipment ice accumulation have a huge impact on ships and marine equipment,causing structural damage to the hull.Affect the normal operation of the equipment,even cause the complete capsizing of the ship,seriously endangering the safety of personnel.Therefore,it is necessary to carry out the most critical technologies for polar marine equipment including ice load forecasting technology,ice mechanics characteristics research,and anti-freezing and deicing of ship equipment.However,due to the complexity of the ice formation process,the material properties of ice are relatively special.Ice is equivalent to a "natural composite material".Its mechanical properties are affected by temperature,salinity,porosity,strain rate,ice crystal size and loading rate.The comprehensive influence of factors cannot consider the mechanical properties of ice from a single perspective.The destruction of ice involves the coupling of force field,temperature field and flow field,which makes numerical simulation difficult,especially for ice.It is difficult to simulate the fracture characteristics of brittle materials using traditional continuum mechanics methods.Peridynamics(PD),as a new nonlocal,meshless material point method,has been widely used in dynamic mechanical analysis of solid materials,static and dynamic crack propagation problems,especially in the simulation of brittle materials.The simulation analysis under high strain rate conditions shows absolute advantages.At the same time,peridynamics has been extended to the field of multi-scale and multi-physics coupling,which is very suitable for simulating the coupling failure characteristics of ice structures in multi-physics.Through the review of the research progress of ice mechanics characteristics at home and abroad,this paper finds that there is no suitable and unified ice constitutive relationship to accurately predict ice load,and there is an urgent need for research on establishing a reasonable ice constitutive relationship model;The physical and mechanical properties are greatly affected by temperature.At present,most researches focus on the damage characteristics of ice under a single force load.Numerical simulations of ice fracture characteristics that take into account temperature are very rare.Numerical simulations are mostly based on the assumption of homogeneous ice models.The non-uniform material properties of ice are not considered,and the model that takes into account the anisotropic material properties of ice has not been established;the numerical simulation of the deicing of the ice-coated structure of ships is very urgent,especially the simulation of thermo-mechanical coupling deicing It is still very rare.New experimental techniques for deicing ship ice-coated structures still need to be developed.Numerical models that take into account the failure of ice in a fluid-solid coupling field under high strain rate conditions are still lacking.Aiming at the above problems,this paper adopts an improved thermo-mechanical coupled peridynamic calculation method to study the thermosmechanical coupling failure characteristics of ice.The establishment of ice constitutive relationship is the basis for accurate prediction of ice load and a basic research topic of polar development strategy.This thesis first aims at the limitations of the existing ice constitutive relationship,compiles a calculation program based on the idea of the peridynamics constitutive model,introduces the constitutive relationship equation into the integral format of the peridynamics,and establishes a universal sexual ice constitutive model library.This article reviews the modeling ideas of peridynamic constitutive equations in Chapter 2.In Chapter 3,the modeling of ice constitutive relations in peridynamics is realized,and four ice peridynamic constitutive are established.The dynamic model solves the numerical simulation of the mechanical properties of ice in different forms,improves the accuracy and universality of the numerical simulation,and provides a basic research reference for the study of the mechanical properties of ice.This part is the basis of the full text,and subsequent chapters are carried out on the basis of its research.Secondly,for the mechanical problems of ice micro-to-macro multi-scale crack characteristics,this paper takes into account the anisotropic material properties and nonuniform characteristics of ice,and proposes the peridynamics modeling idea of heterogeneous ice,which improves the traditional method.The uniform continuum hypothesis improves the simulation accuracy of ice crack characteristics,summarizes the crack growth characteristics of ice with different initial defects,grasps the microscopic crack growth and macroscopic crack growth laws and related relationships of ice,and studies the microscopic and The internal mechanism and influencing factors of the formation of macroscopic cracks,a thermalmechanical coupled crack simulation scheme of the initial defect ice plate containing bubbles and microcracks is proposed.Through the study of the characteristics of ice multi-scale cracks in Chapter 4 of this paper,it aims to predict for engineering applications The thermo-mechanical coupling characteristics of the initial defect ice crack provide a reference.Thirdly,in response to the engineering problem of anti-deicing of frozen structures that has attracted widespread attention in recent years,this paper adopts an improved thermalmechanical coupling peridynamics calculation method,taking into account the effect of the coupling of temperature and force during the deicing process,and takes into account The influence of the interface between ice and frozen structures is established,a peridynamic thermo-mechanical coupling deicing model is established,and the deicing process of the electric pulse EIDI deicing system is simulated.The comparison with the experiment verifies the peridynamic deicing process.The validity and correctness of the dynamic deicing calculation model solves the problem of the thermal load boundary in the thermal-mechanical coupling deicing process,and summarizes the thermal-mechanical coupling temperature distribution and crack propagation mechanism in the deicing process.The effect of temperature on the ice-aluminum dual material is shown.The thermal-mechanical coupling model of nearfield dynamics of ice and frozen structure established in Chapter 5 of this paper realizes for the first time the application of the thermal-mechanical coupling modeling method of near-field dynamics to the numerical simulation of the deicing problem on the surface of frozen structures.Aims to provide basic theoretical research support for ship engineering anti-icing technology.Then,under the background of the application of deicing engineering in the previous chapter,the relevant research work on new deicing technologies for ships and marine structures was carried out.A bubble deicing scheme is designed,which uses the energy generated by the bubbles to remove the ice layer on the surface of the icing structure.Summarizes the de-icing efficiency of different bubble solutions to the ice layer attached to the frozen structure.The bubble deicing technology proposed in Chapter 6 of this article uses bubble energy as a new deicing method,which has a good development prospect in renewable energy utilization,and opens up a way for using new energy to solve the problem of engineering deicing.The new path.Finally,for the engineering problem of breaking ice under explosive load in the fluidstructure coupling field,the calculation method of the near field dynamics method and the smooth particle hydrodynamics method is used to study the similarities between the near field dynamics and the smooth particle hydrodynamics.And their respective advantages,the nearfield dynamics(PD)method is used to simulate solid ice particles,the smooth particle hydrodynamics(SPH)method is used to simulate fluid particles,and the fluid-solid coupling interface is processed by coupling the two particle methods,and simultaneously solves The problems of low computational efficiency and non-convergence in the meshless particle method are discussed.The calculation model of the explosion load ice breaking in the PD-SPH fluidsolid coupling field established in Chapter 7 of this paper realizes the simulation of the blasting process of the high-speed shock wave caused by the explosion load on the ice.The impact of physical damage.Designed to provide a reference for engineering blasting applications. |
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