‘High and heavy’ cargo units are carried around the world on roll-on-roll-off
(ro-ro) ships. These cargo units are loaded and unloaded using rolltrailers and
the risk of rollover for the trailer-cargo unit, during port manoeuvre, often
needs to be assessed in short time. On request by Wallenius Marine AB in
Stockholm, this thesis examines the dynamics of the rolltrailer and different
methods to predict the risk of rollover. The objective is to present a theoretical
foundation for a toolbox that can support the assessment of trailer-load
The study focuses on the effect of running over ‘bumps’. An analytic model,
based on assumptions of the transfer of energy in the rollover scenario, as well
as a simulation, within the SimMechanics environment, was developed and the
two were compared. The models produced almost identical output under the
circumstances specified. The conclusion was that the assumptions made in the
analytic model were reasonable and that the model can be used to characterize
the trailer-cargo unit’s stability. The major reservation was that some dynamic
properties of the trailer had been neglected and that the model does not
account for a sequence of inputs and resonance effects.
The recommendation given is to develop the analytic model to an application
for practical use. A developed SimMechanics simulation, on the other hand,
can be used to examine additional dynamic aspects, resonance effects and
other types of influences. Such results could support the decision making
regarding what safety margin should be applied to the analytic result.
2013. , 41 p.