粘弹-塑性海冰动力学本构模型中的Drucker-Prager屈服准则

针对中小尺度下海冰动力作用过程中的漂移和堆积特征,在粘弹-塑性海冰动力学本构模型中引入了Drucker-Prager(D-P)屈服准则。该模型在海冰屈服前采用Kelvin-Vogit粘弹模型,屈服后采用相关联的正则流动法则。采用该模型对规则海区内的海冰堆积过程进行了数值试验,计算的海冰堆积高度与其解析解一致。另外,在对渤海海冰动力过程中的海冰厚度、密集度、速度以及冰内应力进行的48小时数值模拟中,计算的冰厚分布与卫星遥感资料相符合。基于D-P准则的计算结果与Mohr-Coulomb(M-C)准则的结果相一致,但D-P准则克服了M-C准则计算塑性应力时的奇异现象,进而简化了计算过程。在以上数值模拟中,均采用了光滑质点动力学计算方法。以上数值计算均验证了基于D-P屈服准则的粘弹-塑性本构模型在海冰动力学中的可靠性。

DRUCKER-PRAGER YIELD CRITERIA IN VISCOELASTIC-PLASTIC CONSTITUTIVE MODEL FOR SEA ICE DYNAMICS

Based on the characteristics of sea ice drifting and ridging at meso-small scale, Drucker-Prager (D-P) yield criteria was introduced into the viscoelastic-plastic constitutive(VEP) model for sea ice dynamics. In this model, the Kelvin-Vogit viscoelastic model was adopted in the elastic stage, and the associated normal flow rule was used in the plastic stage. Using the VEP model above, some numerical simulations were carried out to model sea ice ridging process in an idealized rectangular basin. The simulated ice ridge thickness matched the analytical solution well. Moreover, the VEP model with D-P criteria was also applied to the numericalsimulation of the sea ice in Bohai Sea. The simulated thickness, concentration, velocity and ice stress agree with those from the satellite images. The simulated results with D-P criteria were similar to that of Mohr-Coulomb (M-C) criteria, but the singular problem in M-C criteria was overcome with D-P criteria, and the computational efficiency was also improved. In the numerical simulations above, the smoothed particle hydrodynamics was applied in sea ice dynamics. The VEP model with D-P yield criteria was validated with both of the numerical simulations above.