Session: 07-01-01 Arctic Sea Transportation and Environmental Impact

Paper Number: 124047

124047 - On Methodology for a Digital Twin of Ship Propulsion Under Harsh Environmental Conditions 

The propulsion system of a ship is a critical element for its safety and integrity. Therefore, it must be maintained properly to ensure that a vessel is able to fulfil its primary purpose. The need for maintenance is even more pronounced in ships where extreme environmental conditions, such as ice-covered waters, are expected. This is due to an increase in the magnitude and uncertainty of loads and therewith the increase in possible damages if the propulsion system fails. The use of digital twins is becoming increasingly popular in shipping and can also be used for intelligent maintenance and operation prediction of the propulsion system. This paper proposes the methodology of creating such a digital twin with specific focus on the required measurement infrastructure, modelling of components, loads and damage as well as how all of these aspects are combined. The digital twin was created using a polar supply and research vessel, S.A. Agulhas II. Bearings are discussed from the view of high-fidelity simulations and wear modelling. The propeller is modelled as a point mass with the propeller laws for predicting the hydrodynamic torque and thrust. Shaft dynamics are modelled using either a lumped-mass torsional model, a modal model, or a finite element model. Damage of the shaft and the propeller is based on SN-curve fatigue calculations. The motor torque is modelled using an equivalent circuit model while motor damage is modelled by estimating the hottest temperature within the motor windings. Ice-breaking simulations are used as inputs to propeller-ice interaction models to obtain insight into the loads caused by these interactions. The material properties of ice used during simulations are validated using experiments. The need for further validation for low-fidelity models and the need for reduced-order-modelling or surrogate models for high-fidelity models are discussed. Finally, the implementation of this digital twin is discussed on the basis of the developed model and the found problems that still need to be overcome to increase the technology readiness level.

Presenting Author: Franz Von Bock Und Polach Hamburg University of Technology

Presenting Author Biography: Head of the institute for Ship Structural Design and Analysis at the Hamburg University of Technology (TUHH). Before he has been an Acting Professor for Ocean Dynamics in a Changing Climate at the University of Hamburg, Senior Research Engineer at TUHH, Ice Tank Lab Manager at Aalto University and a Naval Architect at Allseas.
He graduated as Master from the Technical University of Berlin and holds a doctoral degree from Aalto University and the Norwegian University of Science and Technology.

He is the current chair of the OOAE division and was an associate editor for the Journal of OMAE.

Authors:

Etienne Purcell Norwegian University of Science and Technology
Amir R. Nejad Norwegian University of Science and Technology
Angelo Böhm Hamburg University of Technology
Lina Sapp Hamburg University of Technology
Jorrid Lund Hamburg University of Technology
Franz Von Bock Und Polach Hamburg University of Technology
Brendon M. Nickerson Stellenbosch University
Anriëtte Bekker Stellenbosch University
Markus Gilges RWTH Aachen University
Ahmed Saleh RWTH Aachen University
Benjamin Lehmann RWTH Aachen University
Georg Jacobs RWTH Aachen University
Mostafa Valavi EDR & Medeso AS
Tobias Kranz Otto Piening GmbH