A regression and beam theory based approach for fatigue assessment of containership structures including bending and torsion contributions
Artikel i vetenskaplig tidskrift, 2015

Container shipping has been expanding dramatically during the last decade. Due to their special structural characteristics, such as the wide breadth and large hatch openings, horizontal bending and torsion play an important role to the fatigue safety of containerships. In this study the fatigue contributions from vertical bending, horizontal bending and torsion are investigated using full-scale measurements of strain records on two containerships. Further, these contributions are compared to results from direct calculations where a nonlinear 3D panel method is used to compute wave loads in time domain. It is concluded that both bending and torsion have significant impacts on the fatigue assessment of containerships. The stresses caused by these loads could be correctly computed by full-ship finite element analysis. However, this requires large computational effort, since for fatigue assessment purposes the FE analysis needs to be carried out for all encountered sea states and operational conditions with sufficient time steps for each condition. In this paper, a new procedure is proposed to run the structure finite element analysis under only one sea condition for only a few time steps. Then, these results are used to obtain a relationship between wave loads and structural stresses through a linear regression analysis. This relation can be further used to compute stresses for arbitrary sea states and operational conditions using the computed wave loads (bending and torsion moments) as input. Based on this proposed method for structure stress analysis, an efficient procedure is formulated and found to be in very good agreement with the full-ship finite element analysis. In addition it is several orders of magnitude more time efficient for fatigue assessment of containership structures.

torsion

horizontal bending

Beam theory

full-scale measurement

fatigue damage

containership

hydrodynamic analysis

finite element analysis

Författare

Wengang Mao

Chalmers, Sjöfart och marin teknik, Marin teknik

Zhiyuan Li

Chalmers, Sjöfart och marin teknik, Marin teknik

Viktor Ogeman

Chalmers, Sjöfart och marin teknik, Marin teknik

Jonas Ringsberg

Chalmers, Sjöfart och marin teknik, Marin teknik

Marine Structures

0951-8339 (ISSN)

Vol. 41 244-266

Ämneskategorier

Maskinteknik

Materialteknik

Farkostteknik

Sannolikhetsteori och statistik

Matematisk analys

Drivkrafter

Hållbar utveckling

Styrkeområden

Transport

Materialvetenskap

Fundament

Grundläggande vetenskaper

DOI

10.1016/j.marstruc.2015.01.001