Objectives and content
To be competitive in shipbuilding industry the application of high tensile steels is indispensable. The traditional steel plate for common use has a yield stress of 235 MPa but it can be observed that he use of high strength steels with yield stresses up to 390 MPa is gradually increasing in conventional and novel ship structures at least for parts of those structures. This leads to lighter ship structures due to the higher allowable stress levels. However, special care has to be taken to reduce the probability of fatigue failure to acceptable levels, because fatigue characteristics of high strength steels are hardly any better than of conventional steel.
Therefore adequate design tools are required to predict failure due to fatigue damage. Improving structural details by applying mechanized or robotized fabrication methods will decrease their sensitivity to fatigue. In that case not only the superior strength properties of high strength steel can fully be exploited but due to improved fabrication methods (technology step) lower cost prices can be realized as well.
In this project it is proposed to investigate the fatigue characteristics of modern high yield strength steels and to develop a design methodology for the strength of ships, made (partly) of this material. The methodology should be applicable for materials with yield stresses up to 690 MPa. Improving structural details by applying mechanized or robotized fabrication methods should decrease their sensitivity to fatigue.
The objectives strived for are:
- A fatigue based methodology for design of structural configurations of welded ship details.
- Promotion of mechanized or robotized fabrication methods to obtain fatigue resistant welded structure details.
- Recommendations for design standards based on probabilistic procedures and for the implementation of these standards in ship structural strength analysis, as given in Classification Rules.
The consortium consist of five shipyards (CdA, Fincantieri, Lisnave, Odense and Schelde), three classification societies (BV, RINA and GL), AF-group (Engineering company), three universities (Lisbon, Hamburg and Goteborg) and the research institutes TNO and VTT.
Funding SchemeCSC - Cost-sharing contracts
191 29 Sollentuna
92565 Imme Rueil-malmaison
412 96 Göteborg
4380 AA Vlissingen