Analysis of accidental iceberg impacts with large passenger vessels and FPSOs

• Main Author: Radhakrishnan, Gowtham
• Other Authors: -, -, Insinööritieteiden korkeakoulu, Kujala, Pentti, Aalto-yliopisto, Aalto University
• Format: Master Thesis
• Language: English
• Published: 2018
• Subjects: ice bergs; ships; ice-structure interaction; accidental ice loads; collision; ALS design criteria; Arctic; Global warming; Iceberg*; Sea ice
• Online Access: https://aaltodoc.aalto.fi/handle/123456789/33730

Nowadays, on account of the rapid increase in the global warming, the extent and thickness of sea ice in the Arctic region is diminishing at a very fast pace. It has even been forecasted that the Arctic region will be ice free in the very near future. Owing to this fact, the Arctic waters are increasingly becoming attractive to different classes of society because of its immense reservoirs of oil and gas, short ship routes in the NE and NW region and attractive tourist places. These activities face the major hurdles from harsh environmental conditions like ice loads, insufficient infrastructure in the Arctic regions and the threats from impact of large ice features. The ships or offshore structures need to be sufficiently strengthened to resist the extreme ice impacts. However, very few data or models do exist that can quantify the extreme ice actions, and in addition the reliability of those data is open to question. For instance, the ice going vessels or offshore structures are designed based on pressure-area curves, but most of the P-A curves are based on Ultimate Limit State (ULS) design whereas the P-A curves for Accidental Limit State (ALS) are very rare. The work carried out in this thesis aims to study the response of structures subjected to those accidental ice impacts. The thesis work can be regarded as a continuation of work carried out by Ekaterina Kim in department of Marine technology, NTNU. In addition, considerable improvements and progress have been achieved in quantifying the accidental ice loads in terms of a novel numerical model. Both FEM and coupled FEM-SPH techniques have been efficiently applied in ice modelling and validated against existing Pressure-Area curves. In addition, computationally demanding spatial envelope curves have been plotted using which the existence and spatial variation of high pressure zones most commonly known as HPZs are effectively studied. Moreover, further step has been taken in applying the FEM-SPH ice modelling in large scale impact simulations. In order to ...