AN ALTERNATIVE SOLUTION FOR INTERACTION OF FLEXURAL GRAVITY WAVES WITH BOTTOM MOUNTED CIRCULAR CYLINDER

The problem of interaction of the flexural gravity waves with the bottom mounted circular cylinder is discussed. Both the linear and second order problems are considered and they are solved by using the eigenfunction expansion principles together with the Boundary Integral Equation technique. The linear solution, which was proposed in the litterature by different authors in the past, is explicitely recovered. For the second order problem, a new original solution strategy is proposed and it was shown that, in the case of water waves, a well known semi-analytical solution is also recovered, proving the generality of the proposed approach

An Overview of the Hydro-Structure Interactions During Sloshing Impacts in the Tanks of LNG Carriers

An overview of the actual status of the modelling of hydro-structure interactions which occur during the severe sloshing impacts in the tanks of LNG Carriers of membrane type is presented. This problem still appears to be open and there are no fully satisfactory methodologies and methods available to solve this problem fully consistently within the so called direct calculation approach. That is why, for the time being, we still have to rely on simplifi ed procedures. Thepaper fi rst summarizes the main technical diffi culties associated with this problem and thendiscusses the different methods which are employed in practice

Hydro Structural Issues in the Design of Ultra Large Container Ships

Specific characteristic of Ultra Large Container Ships (ULCS), compared to other types of ships, is that they are more likely to experience the hydroelastic type of structural response called springing and whipping. This is mainly due to their large dimensions, very large operational speed, and large bow flare. The evaluation of the hydroelastic response and its inclusion into the overall design procedure is significantly more complex problem than the calculation of quasi-static structural response. Classification rules are at the margin of applicability for ULCS and direct calculation is required. In this paper a review of methodology and current status of different methods and tools for structural design of ULCS is presented. Modelling of ship structure as a beam and 3D FE model for preliminary design stage and final checking is mentioned. Different fluid-structure interaction issues are considered, i.e. steady-state and dynamic response, combined with linear and nonlinear wave load. Also, development of numerical methods and software, utilizing model tests and full scale measurements, is presented. Conclusion is directed to the application of the results and the remained open questions

An Overview of the Hydro-Structure Interactions During Sloshing Impacts in the Tanks of LNG Carriers

An overview of the actual status of the modelling of hydro-structure interactions which occur during the severe sloshing impacts in the tanks of LNG Carriers of membrane type is presented. This problem still appears to be open and there are no fully satisfactory methodologies and methods available to solve this problem fully consistently within the so called direct calculation approach. That is why, for the time being, we still have to rely on simplifi ed procedures. Thepaper fi rst summarizes the main technical diffi culties associated with this problem and thendiscusses the different methods which are employed in practice

Quasi-static response of a 19000 TEU class ultra large container ship with a novel mobile deckhouse for maximizing cargo capacity

Modern sea transportation is characterized by ever larger container ships, which require direct calculation procedures and numerical tools to achieve their reliable structural design. There are different attempts to increase the ship loading capacity, as for instance a container ship with a novel mobile deckhouse enabling her to carry additional number of containers, and at the same time changing basic structural properties of the ship. This paper is related to structural design evaluation of a 19,000 TEU ultra large container ship with novel mobile deckhouse for maximizing cargo capacity, particularly relying on quasi-static approach. The ship structural design is evaluated both for fatigue and extreme loads, where conventional container ship of same particulars is used as a reference. Independent analyses of new and conventional design indicate that conventional container ship shows somewhat better performance from viewpoint of fatigue, while global extreme loading is at the same level

Numerička analiza operativnosti kontejnerskog broda na valovitom moru te utjecaj upravljanja na valna opterećenja

Rad prikazuje spoj dva međusobno povezana pristupa upravljanju brodom u nevremenu. Savjeti pomorcima za upravljanje brodom su prvi dio. Drugi dio je utjecaj upravljanja na iznos opterećenja od valova. Savjeti pomorcima su prikazani zadovoljavanjem ili premašivanjem kriterija operativnosti broda. Utjecaj upravljanja brodom na iznos valnog opterećenja je prikazan preko iznosa momenta savijanja na glavnom rebru. Za praktični prikaz poslužio je 9200 TEU brod za prijevoz kontejnera. Numeričkom 3D panel metodom su izračunate prijenosne funkcije komponenti gibanja te su iskorištene za analizu operativnosti u nevremenu opisanom prema preporuci IACS No. 34. Za spektralnu analizu kratkotrajnog stanja mora korišten je 2-P Pierson-Moskowitz spektar valova. Momenti savijanja izračunati su preko „closed-form“ jednadžbi. Rezultati su dijagrami operativnosti i brzina te polarni dijagram. Zaključak rada su prijedlozi za unaprijeđenje pristupa upravljanja brodom u nevremenu te podloge za daljna istraživanja

Hydroelastic response of 19000 TEU class ultra large container ship with novel mobile deckhouse for maximizing cargo capacity

This paper is related to structural design evaluation of 19,000 TEU ultra large container ship, dealing with hydroelastic response, i.e. springing and whipping. It illustrates application of direct calculation tools and methodologies to both fatigue and ultimate strength assessment, simultaneously taking into account ship motions and her elastic deformations. Methodology for springing and whipping assessment within so called WhiSp notation is elaborated in details, and in order to evaluate innovative container ship design with increased loading capacity, a series of independent hydroelastic computations for container ship with mobile deckhouse and conventional one are performed with the same calculation setup. Fully coupled 3D FEM – 3D BEM model is applied, while the ultimate bending capacity of hull girder is determined by means of MARS software. Beside comparative analysis of representative quantities for considered ships, relative influence of hydroelasticity on ship response is addressed