Prof Nigel White will be giving the FSI seminar on Thursday 10th march, 12;00-13:00 in B176L room 1125. All are welcome.
Typically, Lloyd’s Rules for the design and construction of ships develop on a largely evolutionary process, however there are often very rapid advances in ship size or design which mean that the evolution process is questionable. The rules and design procedures are also updated on the basis of improved design technology. There has been a huge growth in the size of container ships, in 2000 the biggest ships were 8000 TEU with a length of 300m and beam of 43m, today the ultra large container ships (ULCS) 21,000 TEU have a length of 400m and beam of 60m. This growth is testing the existing evolutionary process, however current computer power means that we can develop procedures that allow us to assess the very complex effects of whipping and springing on the structure of these ULCS.
Containerships are unique in that they have very large deck openings, long hull forms, large bow flare and operate at fairly high operational speeds (roughly 18 knots or over). Each of these pose challenges on their own, but when combined the effect is potentially even more severe. The large deck openings mean that the torsional rigidity of the vessel is low and very high strength and thick steel is required for the deck and hatch coamings, the bow flare and high speed mean that the impact loads due to waves are high (whipping), the long length means that the natural vibration frequency of the hull girder is low and close to the encounter wave period due to the high speed (springing). LR has been working on the assessment of these issues over recent years and has taken the work developed by the universities back in the early 90s (including Southampton) into practical procedures that can be consistently applied.
The presentation gives an oversight into some of the issues related to the assessment of whipping and springing for ULCS. The need for such procedures was highlighted by the recent container ship total losses where whipping was a contributory factor.
Biography
Nigel is a Senior Principal Hydrodynamicist at Lloyds Register and works in the Structural Analysis and Hydrodynamics research group. He has also been recently elected as a Visiting Professor at the University of Southampton in the Ship Science department. Nigel has been with LR for 23 years and is the lead engineer for the development of Lloyds Register’s procedures in areas related to hydrodynamic expertise including ship motions, hydroelasticity (whipping/springing responses), impact loads, sloshing loads, dynamic load application, fluid structure interactions, etc. for all ship types. He has also been involved in many of the IACS working groups involving loads on ships.
