Modelling Cutterhead/Soil Interaction for a Cutter Suction Dredger in Waves
CEDA Dredging Days 2019
A. Blanken and J.G. Los
Abstract: Understanding the dynamic behaviour of a Cutter Suction Dredger (CSD) in waves is important for the design of CSD’s. At Royal IHC the simulation software DODO (Dynamic Operations in Dredging and Offshore) has been used for many years to simulate the dynamic behaviour of dredging and offshore vessels, combining vessel hydrodynamics, multibody dynamics, and soil mechanics. For CSD’s the software has frequently been utilized for workability studies and equipment design. The forces at the cutterhead however, are often neglected or very much simplified.
The cutterhead-soil interaction is very complex, but can be important for evaluation of concept designs and design improvements of a CSD. To gain more knowledge on the cutting process, e.g. for cutterhead design, IHC developed the simulation software Gibraltar, that in detail calculates the interaction of a complete cutterhead with the breach on the scale of each individual cutter tooth. For a simulation of a complete CSD in waves, however, such detail is computationally too expensive. Therefore a new cutting model is developed and implemented in DODO, describing the cutterhead-soil interaction on the scale of the complete cutterhead.
This paper discusses aforementioned model and the challenges that were encountered during its development, such as modelling of computationally inexpensive cutting forces and soil, dealing with initial conditions and grid size.
Keywords: Cutterhead-soil interaction, multibody dynamics, cutter suction dredger, simulation model