Enhancing the structural stress assessment of distorted lightweight ship deck structures
Pursuing enhanced ship performance has driven lightweight structural solutions into modern cruise ship design. Among available strategies, the employment of thin steel plates in welded superstructure decks appears achievable, more sustainable and economically feasible. However, thin plates are susce...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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Aalto University
2024
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Online Access: | https://aaltodoc.aalto.fi/handle/123456789/128397 |
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Aalto University Publication Archive (Aaltodoc) |
op_collection_id |
ftaaltouniv |
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English |
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Marine engineering structural stress thin plates geometric non-linearity computational modelling lightweight design |
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Marine engineering structural stress thin plates geometric non-linearity computational modelling lightweight design Mancini, Federica Enhancing the structural stress assessment of distorted lightweight ship deck structures |
topic_facet |
Marine engineering structural stress thin plates geometric non-linearity computational modelling lightweight design |
description |
Pursuing enhanced ship performance has driven lightweight structural solutions into modern cruise ship design. Among available strategies, the employment of thin steel plates in welded superstructure decks appears achievable, more sustainable and economically feasible. However, thin plates are susceptible to complex welding-induced distortions, which cannot be disregarded in the fatigue and limit state analysis of the welded structure. Since the effect of those distortions is not entirely considered by ship design rules, its evaluation requires full-field scanning of welded plates to be modelled in costly numerical analyses. This thesis investigates computationally efficient structural stress assessment approaches on buttwelded 4 mm-thick plates in stiffened panels from actual shipyard production, resulting in average to severe initial distortions according to classifications in the marine structures community. The distortion measurement and characterisation are followed by the 3D geometrically non-linear finite element analysis (GNL-FEA) of the panels under tension, simulating the effect of hull girder bending on the superstructure decks. The 3D model is validated against uni-axial tensile tests on the panels. Thereafter, a gradual scale reduction from 3D to 2D and 1D models is performed numerically and analytically, where the von Kármán kinematic assumption accounts for the geometric non-linearity. As a last step, a beam model is developed for a simple half-sine curvature and considering the effect of weld rigidity. In characterising the distortions, both amplitude and slope parameters need to be considered. For multi-buckled shapes with amplitudes below the plate thickness, a 2D analytical model neglecting the geometric discontinuity due to the weld can predict global structural stresses over the panel plate field; however, the weld cross-section must be considered in the local structural stress assessment of the welded area. For the latter, the 1D GNL-FEA of a distorted longitudinal profilelocated within 60% ... |
author2 |
Romanoff, Jani, Prof., Aalto University, Department of Mechanical Engineering, Finland Insinööritieteiden korkeakoulu School of Engineering Konetekniikan laitos Department of Mechanical Engineering Remes, Heikki, Prof., Aalto University, Department of Mechanical Engineering, Finland Marine and Arctic Technology Aalto-yliopisto Aalto University |
format |
Doctoral or Postdoctoral Thesis |
author |
Mancini, Federica |
author_facet |
Mancini, Federica |
author_sort |
Mancini, Federica |
title |
Enhancing the structural stress assessment of distorted lightweight ship deck structures |
title_short |
Enhancing the structural stress assessment of distorted lightweight ship deck structures |
title_full |
Enhancing the structural stress assessment of distorted lightweight ship deck structures |
title_fullStr |
Enhancing the structural stress assessment of distorted lightweight ship deck structures |
title_full_unstemmed |
Enhancing the structural stress assessment of distorted lightweight ship deck structures |
title_sort |
enhancing the structural stress assessment of distorted lightweight ship deck structures |
publisher |
Aalto University |
publishDate |
2024 |
url |
https://aaltodoc.aalto.fi/handle/123456789/128397 |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
Aalto University publication series DOCTORAL THESES 123/2024 [Publication 1]: Mancini F., Remes H., Romanoff J., Lehto P., Rautiainen M., Niraula A., Niemelä A. Shape characterisation and impact on the structural behaviour of initially distorted, 4-mm thick ship-deck stiffened panels. In Marine and Offshore Structures, MARSTRUCT2023, Sweden, 9, February 2023. DOI:10.1201/9781003399759-70 [Publication 2]: Mancini F., Remes H., Romanoff J. On the modelling of distorted thin-walled stiffened panels via a scale reduction approach for a simplified structural stress analysis. Thin-Walled Structures, 197,0263-8231, January 2024. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-202402072370. DOI:10.1016/j.tws.2024.111637 [Publication 3]: Mancini F., Remes H., Romanoff J., Reinaldo Goncalves B. Stress magnification factor for angular misalignment between plates with weldinginduced curvature. Welding in The World, 64, 729-751, March 2020. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-202004282855. DOI:10.1007/s40194-020-00866-7 [Publication 4]: Mancini F., Remes H., Romanoff J. A stress magnification factor for plates with welding-induced curvatures. In Proceedings of the ASME 2020 39th International. Conference on Ocean, Offshore and Arctic Engineering, OMAE2020, Virtual, August 2020. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-2020123160227. DOI:10.1115/OMAE2020-18094 [Publication 5]: Mancini F., Remes H., Romanoff J., Gallo P. Influence of weld rigidity on the non-linear structural response of beams with a curved distortion. Engineering Structures, August 2021. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-202109159153. DOI:10.1016/j.engstruct.2021.113044 978-952-64-1869-8 (electronic) 978-952-64-1868-1 (printed) 1799-4942 (electronic) 1799-4934 (printed) 1799-4934 (ISSN-L) https://aaltodoc.aalto.fi/handle/123456789/128397 URN:ISBN:978-952-64-1869-8 |
op_doi |
https://doi.org/10.1201/9781003399759-7010.1016/j.tws.2024.11163710.1007/s40194-020-00866-710.1115/OMAE2020-1809410.1016/j.engstruct.2021.113044 |
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1802639140893753344 |
spelling |
ftaaltouniv:oai:aaltodoc.aalto.fi:123456789/128397 2024-06-23T07:48:48+00:00 Enhancing the structural stress assessment of distorted lightweight ship deck structures Mancini, Federica Romanoff, Jani, Prof., Aalto University, Department of Mechanical Engineering, Finland Insinööritieteiden korkeakoulu School of Engineering Konetekniikan laitos Department of Mechanical Engineering Remes, Heikki, Prof., Aalto University, Department of Mechanical Engineering, Finland Marine and Arctic Technology Aalto-yliopisto Aalto University 2024 84 + app. 82 application/pdf https://aaltodoc.aalto.fi/handle/123456789/128397 en eng Aalto University Aalto-yliopisto Aalto University publication series DOCTORAL THESES 123/2024 [Publication 1]: Mancini F., Remes H., Romanoff J., Lehto P., Rautiainen M., Niraula A., Niemelä A. Shape characterisation and impact on the structural behaviour of initially distorted, 4-mm thick ship-deck stiffened panels. In Marine and Offshore Structures, MARSTRUCT2023, Sweden, 9, February 2023. DOI:10.1201/9781003399759-70 [Publication 2]: Mancini F., Remes H., Romanoff J. On the modelling of distorted thin-walled stiffened panels via a scale reduction approach for a simplified structural stress analysis. Thin-Walled Structures, 197,0263-8231, January 2024. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-202402072370. DOI:10.1016/j.tws.2024.111637 [Publication 3]: Mancini F., Remes H., Romanoff J., Reinaldo Goncalves B. Stress magnification factor for angular misalignment between plates with weldinginduced curvature. Welding in The World, 64, 729-751, March 2020. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-202004282855. DOI:10.1007/s40194-020-00866-7 [Publication 4]: Mancini F., Remes H., Romanoff J. A stress magnification factor for plates with welding-induced curvatures. In Proceedings of the ASME 2020 39th International. Conference on Ocean, Offshore and Arctic Engineering, OMAE2020, Virtual, August 2020. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-2020123160227. DOI:10.1115/OMAE2020-18094 [Publication 5]: Mancini F., Remes H., Romanoff J., Gallo P. Influence of weld rigidity on the non-linear structural response of beams with a curved distortion. Engineering Structures, August 2021. Full text in Acris/Aaltodoc: https://urn.fi/URN:NBN:fi:aalto-202109159153. DOI:10.1016/j.engstruct.2021.113044 978-952-64-1869-8 (electronic) 978-952-64-1868-1 (printed) 1799-4942 (electronic) 1799-4934 (printed) 1799-4934 (ISSN-L) https://aaltodoc.aalto.fi/handle/123456789/128397 URN:ISBN:978-952-64-1869-8 Marine engineering structural stress thin plates geometric non-linearity computational modelling lightweight design G5 Artikkeliväitöskirja text Doctoral dissertation (article-based) Väitöskirja (artikkeli) 2024 ftaaltouniv https://doi.org/10.1201/9781003399759-7010.1016/j.tws.2024.11163710.1007/s40194-020-00866-710.1115/OMAE2020-1809410.1016/j.engstruct.2021.113044 2024-06-04T14:22:32Z Pursuing enhanced ship performance has driven lightweight structural solutions into modern cruise ship design. Among available strategies, the employment of thin steel plates in welded superstructure decks appears achievable, more sustainable and economically feasible. However, thin plates are susceptible to complex welding-induced distortions, which cannot be disregarded in the fatigue and limit state analysis of the welded structure. Since the effect of those distortions is not entirely considered by ship design rules, its evaluation requires full-field scanning of welded plates to be modelled in costly numerical analyses. This thesis investigates computationally efficient structural stress assessment approaches on buttwelded 4 mm-thick plates in stiffened panels from actual shipyard production, resulting in average to severe initial distortions according to classifications in the marine structures community. The distortion measurement and characterisation are followed by the 3D geometrically non-linear finite element analysis (GNL-FEA) of the panels under tension, simulating the effect of hull girder bending on the superstructure decks. The 3D model is validated against uni-axial tensile tests on the panels. Thereafter, a gradual scale reduction from 3D to 2D and 1D models is performed numerically and analytically, where the von Kármán kinematic assumption accounts for the geometric non-linearity. As a last step, a beam model is developed for a simple half-sine curvature and considering the effect of weld rigidity. In characterising the distortions, both amplitude and slope parameters need to be considered. For multi-buckled shapes with amplitudes below the plate thickness, a 2D analytical model neglecting the geometric discontinuity due to the weld can predict global structural stresses over the panel plate field; however, the weld cross-section must be considered in the local structural stress assessment of the welded area. For the latter, the 1D GNL-FEA of a distorted longitudinal profilelocated within 60% ... Doctoral or Postdoctoral Thesis Arctic Aalto University Publication Archive (Aaltodoc) |