Application of an extended inverse method for the determination of ice-induced loads on ships
With the opening of more Arctic shipping routes, the motivation to design safe and efficient ice-going ships has increased. Recently, knowledge of ship-ice interactions and the mechanics of icebreaking processes has improved through numerous full-scale studies; however, the understanding of precise...
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ftaaltouniv:oai:aaltodoc.aalto.fi:123456789/33777 2023-05-15T14:56:36+02:00 Application of an extended inverse method for the determination of ice-induced loads on ships Adams, Jillian Hogström, Per Valtonen, Ville Insinööritieteiden korkeakoulu Kujala, Pentti Aalto-yliopisto Aalto University 2018-08-20 application/pdf https://aaltodoc.aalto.fi/handle/123456789/33777 en eng https://aaltodoc.aalto.fi/handle/123456789/33777 URN:NBN:fi:aalto-201809034902 ship-ice interaction ice-induced load inverse method full-scale strain measurements icebreaker Arctic G2 Pro gradu, diplomityö Master's thesis Diplomityö 2018 ftaaltouniv 2022-12-15T19:17:54Z With the opening of more Arctic shipping routes, the motivation to design safe and efficient ice-going ships has increased. Recently, knowledge of ship-ice interactions and the mechanics of icebreaking processes has improved through numerous full-scale studies; however, the understanding of precise ice-induced pressures and load heights requires refinement to improve design methods. This thesis aims to further the development of an inverse engineering method to determine the nature of ice loads experienced by ships. The method uses full-scale strain measurements to estimate local pressures on the ship's structures. The data studied in this thesis was collected on the oblique icebreaker Baltika while operating in the Russian Arctic over a two-year period. The inverse method uses an influence coefficient matrix to relate the measured strain to the input pressure load. Using FEM, strain response functions are fitted at each sensor to generate the terms of the influence coefficient matrix. An optimisation routine is used to solve the inverse force-strain relationship and predict the load patch shape and pressure induced by the ice impact. The hourly maximum strain measurements are identified and analysed to estimate the applied load and contact area during ice impact events. A general analysis of 250 significant impact events reveals that the applied pressure is on the order of 10-25 MPa and the load height is on the order of 1-3 cm. The detailed analysis of 98 individual impact events demonstrates that the load height during impact remains markedly constant for the duration of the contact. Furthermore, the pressure distribution between load carrying structures is investigated. Based on the results, the pressure distribution between structural members is random and independent of the supporting structure. Master Thesis Arctic Icebreaker Aalto University Publication Archive (Aaltodoc) Arctic |
institution |
Open Polar |
collection |
Aalto University Publication Archive (Aaltodoc) |
op_collection_id |
ftaaltouniv |
language |
English |
topic |
ship-ice interaction ice-induced load inverse method full-scale strain measurements icebreaker Arctic |
spellingShingle |
ship-ice interaction ice-induced load inverse method full-scale strain measurements icebreaker Arctic Adams, Jillian Application of an extended inverse method for the determination of ice-induced loads on ships |
topic_facet |
ship-ice interaction ice-induced load inverse method full-scale strain measurements icebreaker Arctic |
description |
With the opening of more Arctic shipping routes, the motivation to design safe and efficient ice-going ships has increased. Recently, knowledge of ship-ice interactions and the mechanics of icebreaking processes has improved through numerous full-scale studies; however, the understanding of precise ice-induced pressures and load heights requires refinement to improve design methods. This thesis aims to further the development of an inverse engineering method to determine the nature of ice loads experienced by ships. The method uses full-scale strain measurements to estimate local pressures on the ship's structures. The data studied in this thesis was collected on the oblique icebreaker Baltika while operating in the Russian Arctic over a two-year period. The inverse method uses an influence coefficient matrix to relate the measured strain to the input pressure load. Using FEM, strain response functions are fitted at each sensor to generate the terms of the influence coefficient matrix. An optimisation routine is used to solve the inverse force-strain relationship and predict the load patch shape and pressure induced by the ice impact. The hourly maximum strain measurements are identified and analysed to estimate the applied load and contact area during ice impact events. A general analysis of 250 significant impact events reveals that the applied pressure is on the order of 10-25 MPa and the load height is on the order of 1-3 cm. The detailed analysis of 98 individual impact events demonstrates that the load height during impact remains markedly constant for the duration of the contact. Furthermore, the pressure distribution between load carrying structures is investigated. Based on the results, the pressure distribution between structural members is random and independent of the supporting structure. |
author2 |
Hogström, Per Valtonen, Ville Insinööritieteiden korkeakoulu Kujala, Pentti Aalto-yliopisto Aalto University |
format |
Master Thesis |
author |
Adams, Jillian |
author_facet |
Adams, Jillian |
author_sort |
Adams, Jillian |
title |
Application of an extended inverse method for the determination of ice-induced loads on ships |
title_short |
Application of an extended inverse method for the determination of ice-induced loads on ships |
title_full |
Application of an extended inverse method for the determination of ice-induced loads on ships |
title_fullStr |
Application of an extended inverse method for the determination of ice-induced loads on ships |
title_full_unstemmed |
Application of an extended inverse method for the determination of ice-induced loads on ships |
title_sort |
application of an extended inverse method for the determination of ice-induced loads on ships |
publishDate |
2018 |
url |
https://aaltodoc.aalto.fi/handle/123456789/33777 |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Icebreaker |
genre_facet |
Arctic Icebreaker |
op_relation |
https://aaltodoc.aalto.fi/handle/123456789/33777 URN:NBN:fi:aalto-201809034902 |
_version_ |
1766328686605238272 |