Because global warming is speeding up the melting of the Polar Regions, navigation
through ice-infested areas is becoming more frequent. Therewith, new maritime
routes are being opened, which were impractical a few years ago.
The naval industry has been very interested in studying the eects that sea ice produces
when it collides with the ship’s hull. Proof of that is the signicant dierence
that characterizes the design and shape of an icebreaker ship versus one that does
Consequently, the main master’s thesis target is the theoretical study of sea ice behaviour
for an accurate numerical simulation when applying innovative techniques
such as the Discrete Element Method (DEM) to simulate ship-ice interactions.
First and foremost, a compilation is presented in the form of a theoretical study of
the physical and mechanical behaviour of rst-year (FY) sea ice. Thus, a backed
knowledge of the properties and their range of values is acquired to be subsequently
applied in the numerical simulations.
In addition, a brief analysis of the main characteristics of icebreaker ships and especially
the problem that occurs when navigating in frozen seas is made. From this,
it is essential to dierentiate between unbroken and broken ice elds.
From the latter originates a detailed analysis of the types of fracture that occur in
an ice oe when it is loaded by an icebreaker ship. According to the thickness and
dimensions of the ice oe, the theoretical and expected failure mode is dened.
A DEM formulation from the DEMpack group of CIMNE is used and commented in
detail. The interaction of a packed group of discrete particles, duly cohesive, allows
to model an ice sheet and study the possible fractures and their propagation.
Finally a set of numerical simulations are carried out. In the rst group it is presented
how a continuous sheet of level-ice breaks against an installed cone in a
vertical structure. The inuence of the slope of the cone is studied both in the type
of breakage and for the magnitude of the ice loads.
In the second group a detailed and applied study of the types of fracture produced
in nite size ice oes is presented, varying their thickness and sizes. These are
understood as isolated elements of a discontinuous sea of ice formed by separated
blocks, the connement of which is very small or null. In addition, the inuence of
thickness and dimensions on loads is studied.
Lastly, a simulation is performed in which it is analysed how a 3D model of a real
icebreaker vessel advances through an unbroken ice eld composed of 1 meter thick
FY level-ice. The results are compared with those expected and seen in real navigations
and the forces generated are also used to estimate the required propulsion
Key words: Discrete Element Method (DEM), sea level-ice, oe-ice, ice fractures
and icebreaker ship-ice interactions.