Analytical calculation of ice loads

Field of research:
Ice loads

01st Jan. 2016 – 30th May 2016

Project leader
Prof. DSc. (Tech.) Sören Ehlers

Werner-Sutor Stiftung

Ships navigating in ice experience added resistance due to ship-ice interaction. Ship-ice interaction is a complex process that depends on ship parameters (mainly hull shape and speed in ice) and ice properties (e.g. thickness, strength, type). The assessment of icebreaking resistance component includes (a) modeling of the local contacts as the ship advances though the ice field, (b) calculation of the interaction forces, and (c) ice failure modeling. Unlike experiments in model ice tanks, numerical simulations and direct calculations are not subject to the scale effects. These scale effects between model ice and full-scale ice present a real challenge in model testing (von Bock und Polach & Ehlers, 2015). Ship-ice interaction simulations, however, face certain challenges too. Obtained results are a trade-off between the required accuracy and the simulation efficiency, sometimes even simulability. To determine the accuracy of existing empirical and analytical ice resistance prediction methods, they are to be analyzed in detail and compared with available full-scale measurements. This is typically done by the authors of each method for selected ships, although only for a presented method. However, a global comparison of all existing methods and their application to a series of modern ships does not exist. Consequently, the resulting accuracy is not yet adequately assessed.

Therefore, the aim of this project is to create an overview of the existing empirical and analytical ice resistance prediction methods. Further, the methods are to be presented in Matlab to facilitate their application and perform comparative calculations so as to determine the accuracy of each method. Full-scale ice resistance measurements obtained from the sea trials will be used in the assessment of accuracy of the existing methods.