A Lattice Model to Simulate Ice-Structure Interaction

Abstract

The interaction between ice sheets and offshore structures is of key importance in the design of offshore platforms in the Arctic. Unfortunately, due to the complexity of ice material the use of small-scale experiments is problematic if one aims at drawing some conclusions about the forces exerted on large-scale structures such as oil rigs. As a preliminary work this paper proposes a discrete numerical model to investigate the interaction between an ice sheet and a rigid structure. The behavior of ice is modelled by a two dimensional lattice model, in which inhomogeneity and possible failure of ice are incorporated. According to the numerical results such a model seems able to capture the main trends involved in ice sheets cracking. This is an essential step towards predicting interaction forces between ice and structure.

A free, square, point-loaded ice sheet: A finite element-discrete element approach

“…1 A body of literature explores the use of lattice-, hybrid FE-DE-, and FE-based numerical methods to model a floating ice sheet, its fracture, and/or interaction with an offshore structure [Hocking, 1992;Jirásek and Bažant, 1995a;Hopkins, 1998;Sayed and Timco, 1998;Selvadurai and Introduction Sepehr, 1999;Sand, 2008;Dorival et al, 2008;Konuk et al, 2009;Gürtner, 2009;Paavilainen et al, 2009;Lu et al, 2014Lu et al, , 2015Lu et al, , 2016Herman, 2016;van den Berg, 2016]. Lattices of either axial/rotational spring-, truss-, or beam-type were exploited in [Jirásek and Bažant, 1995a;Sayed and Timco, 1998;Dorival et al, 2008;Paavilainen et al, 2009;Herman, 2016], and [van den Berg, 2016]. Of these, the models of Jirásek and Bažant [1995a]; Sayed and Timco [1998]; Dorival et al [2008]; Paavilainen et al [2009], and Herman [2016] were formulated in a two-dimensional space and only that of van den Berg [2016] in a three-dimensional space.…”

“…Lattices of either axial/rotational spring-, truss-, or beam-type were exploited in [Jirásek and Bažant, 1995a;Sayed and Timco, 1998;Dorival et al, 2008;Paavilainen et al, 2009;Herman, 2016], and [van den Berg, 2016]. Of these, the models of Jirásek and Bažant [1995a]; Sayed and Timco [1998]; Dorival et al [2008]; Paavilainen et al [2009], and Herman [2016] were formulated in a two-dimensional space and only that of van den Berg [2016] in a three-dimensional space. This thesis focuses on a three-dimensional method.…”

“…In order to get an idea of how an unstructured lattice behaves elastically, constitutive tests such as those reported in this thesis should be performed. Of the previous works that used lattice-based meshes, the meshes in [Jirásek and Bažant, 1995a;Sayed and Timco, 1998;Dorival et al, 2008;Herman, 2016], and[van den Berg, 2016] were unstructured, with no test results given, however.…”