Modelling of Ship Superstructure Icing: Application to Ice Bridge Simulators

Abstract

Increasing activities on high north regions bring about a demand of safety ship navigation. Under severe weather condition considerable amounts of ice may accumulate on marine structures. Ice bridge simulator is of importance in terms of training for qualified maritime personal. The new ice module to fit for additional problem for the ship icing is introduced with low reality into bridge simulator. Regarding this our aim is to develop ice model that calculate ice load on the ship structure and stability change include parameters of air temperature, relative wind speed, wave height etc. As a result of literature survey theoretical and empirical method with its algorithm is studied. The ice thickness on cylinder and plate as a representative element of the structures are calculated as a function of liquid water content, relative wind speed and freezing fraction for simplified ship superstructures to include the effect of trapped water on deck. Since we have to deal with several thousand of element to be calculated every seconds including iteration process, computer should be used, hence new ice model is proposed by using computer language C++. In case study 300 tonnage size coast guard vessel is selected as a model ship. Under assumptions that those external parameters are stable in the duration of simulation, proposed model is validated. As a result proposed model could simulate total ice load and following stability change, with error of rolling period after 20 hours simulation being 0.14 sec compared to full scale measurement.