Bonded discrete element simulations of sea ice with non-local failure:
Applications to Nares Strait
Abstract
The discrete element method (DEM) can provide detailed descriptions of
sea ice dynamics that explicitly model floes and discontinuities in the
ice, which can be challenging to represent accurately with current
models. However, floe-scale stresses that inform lead formation in sea
ice are difficult to calculate in current DEM implementations. In this
paper, we use the ParticLS software library to develop a DEM that models
the sea ice as a collection of discrete rigid particles that are
initially bonded together using a cohesive beam model that approximates
the response of an Euler-Bernoulli beam located between particle
centroids. Ice fracture and lead formation are determined based on the
value of a non-local Cauchy stress state around each particle and a
Mohr-Coulomb fracture model. Therefore, large ice floes are modeled as
continuous objects made up of many bonded particles that can interact
with each other, deform, and fracture. We generate particle
configurations by discretizing the ice in MODIS satellite imagery into
polygonal floes that fill the observed ice shape and extent. The model
is tested on ice advecting through an idealized channel and through
Nares Strait. The results indicate that the bonded DEM model is capable
of qualitatively capturing the dynamic sea ice patterns through
constrictions such as ice bridges, arch kinematic features, and lead
formation. In addition, we apply spatial and temporal scaling analyses
to illustrate the model’s ability to capture heterogeneity and
intermittency in the simulated ice deformation.