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A modified discrete element model for sea ice dynamics

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Acta Oceanologica Sinica 2014年第1期33卷 56-63页

作者： LI Baohui LI Hai LIU Yu WANG Anliang JI Shunying Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Ocean Circulation and Waves (KLOCAW ) Chinese Academy of Sciences Graduate School of Chinese Academy of Sciences National Marine Environment Forecast Center State Oceanic Administration Key Laboratory of Research on Marine Hazards Forecasting State Oceanic Administration State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology

Considering the discontinuous characteristics of sea ice on various scales,a modified discrete element model（DEM） for sea ice dynamics is developed based on the granular material rheology.In this modified DEM,a soft sea ice particle element is introduced as a self-adjustive particle size function.Each ice particle can be treated as an assembly of ice floes,with its concentration and thickness changing to variable sizes under the conservation of mass.In this model,the contact forces among ice particles are calculated using a viscous-elastic-plastic model,while the maximum shear forces are described with the Mohr-Coulomb friction law.With this modified DEM,the ice flow dynamics is simulated under the drags of wind and current in a channel of various widths.The thicknesses,concentrations and velocities of ice particles are obtained,and then reasonable dynamic process is analyzed.The sea ice dynamic process is also simulated in a vortex wind field.Taking the influence of thermodynamics into account,this modified DEM will be improved in the future work.

关键词： sea ice dynamics modified discrete element model contact force model numerical simulation

A viscoelastic-plastic constitutive model with Mohr-Coulomb yielding criterion for sea ice dynamics

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Acta Oceanologica Sinica 2005年第4期24卷 54-65页

作者： JI Shunying SHEN Hung Tao WANG Zhilian SHEN H Hayley YUE Qianjin State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116023 China Department of Civil and Environmental Engineering Clarkson University Potsdam New York 13699-5710 USA

A new viscoelastic-plastic （VEP） constitutive model for sea ice dynamics was developed based on continuum mechanics. This model consists of four components： Kelvin-Vogit viscoelastic model, Mohr-Coulomb yielding criterion, associated normality flow rule for plastic rehololgy, and hydrostatic pressure. The numerical simulations for ice motion in an idealized rectangular basin were made using smoothed particle hydrodynamics （SPH） method, and compared with the analytical solution as well as those based on the modified viscous plastic（VP） model and static ice jam theory. These simulations show that the new VEP model can simulate ice dynamics accurately. The new constitutive model was further applied to simulate ice dynamics of the Bohai sea and compared with the traditional VP, and modified VP models. The results of the VEP model are compared better with the satellite remote images, and the simulated ice conditions in the JZ20-2 oil platform area were more reasonable.

关键词： sea ice dynamics constitutive model viscous plasticity viscoelastic-plastic model Molar-Coulomb criterion

Mechanical and numerical models for sea ice dynamics on small-meso scale

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Chinese Journal of Polar Science 2008年第2期19卷 237-248页

作者：季顺迎王安良李海岳前进 State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Key Laboratory of Polar Science of the State Oceanic Administration National Marine Environment Forecast Center

On small-meso scale, the sea ice dynamic characteristics are quite different from that on large scale. To model the sea ice dynamics on small-meso scale, a new elastic-viscous-plastic （EVP） constitutive model and a hybrid Lagrangian- Eulerian （HLE） numerical method are developed based on continuum theory. While a modified discrete element model （DEM） is introduced to model the ice cover at discrete state. With the EVP constitutive model, the numerical simulation for ice ridging in an idealized rectangular basin is carried out and the results are comparable with the analytical solution of jam theory. Adopting the HLE numerical model, the sea ice dynamic process is simulated in a vortex wind field. The furthering application of DEM is discussed in details for modeling the discrete distribution of sea ice. With this study, the mechanical and numerical models for sea ice dynamics can be improved with high precision and computational efficiency.

关键词： sea ice dynamics constitutive model numerical method discrete element model small-meso scale.