1,721,081 research outputs found
Application of 2D hydroelasticity theory to investigate the failure of a containership
No full textThis paper focuses on the investigation carried out on the failure of the MSC Napoli using two-dimensional (2D) symmetric (i.e. vertical bending) hydroelasticity analysis. The aim of the investigation was to assess the influence of whipping-induced loads on the structural strength of this containership. Relevant structural, hydrostatic and operational data were provided. The calculations were carried out in head regular and long-crested irregular waves. Both cases included the effect of bottom slamming only. Global wave-induced loads were evaluated along the hull, focusing in particular in the vicinity of the engine room. The investigation showed that whipping, due to bottom slamming, is only important for severe seas. The investigation also showed that the keel stresses, in way of the engine room, can be as large as the keel stresses at amidships
The effect of structural discontinuity on antisymmetric response of a container ship
No full textRecent trends in capacity, hence size, growth in container ships have increased the importance of torsion, particularly how it is influenced by the large deck openings and structural discontinuities present in such ships. This paper investigates the consequences of these effects on the ‘dry’ antisymmetric modal characteristics and consequent wave-induced loads. A beam model with more accurate representation of warping and structural discontinuities is applied to a box beam to assess these influences and compare predictions of natural frequencies and mode shapes with previous calculations and finite element (FE) predictions. The analysis is subsequently applied to a feeder containership travelling in regular oblique waves and resultant loads are compared with predictions obtained from previous two (2D) - and three-dimensional (3D) hydroelasticity analyses
Coupling between flexible ship and liquid sloshing using potential flow analysis and their effect on wave induced loads
No full textThe purpose of this study is to investigate the influence of hull flexibility on the hydrodynamic forces and moments associated with liquid sloshing, as well as the dynamic characteristics = (e.g. resonance frequencies) of the whole system. For this purpose, symmetric and antisymmetric structural responses such as bending moments and torsional moment, etc. for an idealized LNG carrier in head, beam and quartering regular waves are studied with and without coupling effect from liquid sloshing
The influence of forward speed and nonlinearities on the dynamic behaviour of a container ship in regular waves
No full textThe aim of this paper is to compare the heave and pitch motions for the S175 containership obtained from frequency domain linear and time domain partly nonlinear potential flow analyses. The frequency domain methods comprise the pulsating and the translating pulsating Green’s function methods, with the relevant source distribution over the mean wetted surface of the hull
Hydroelasticity of ships: taking stock and moving forward
No full textInvestigations into Hydroelasticity theory commenced in the 1970s. It has since been employed to predict the responses of a wide range of marine structures, namely ships, offshore structures, VLFS and aquaculture structures. A dedicated conference on Hydroelasticity in Marine Technology takes place once every three years, with the next one at Southampton, in 2009. These are indications that hydroelasticity is an established method. The aims of this keynote paper are to illustrate some of the applications of hydroelasticity theory to ships, with particular reference to recent and ongoing developments and, particularly, on the effects of nonlinearities and viscous flows, and discuss possible future developments
Loads on ships and offshore structures
No full textThe Loads Committee of the International Ship and Offshore Structures Congress (ISSC) critically reviews the state of the art of environmental and operational loads. Amongst these, elements more relevant to the offshore industry will be presented in this paper. These comprise wave-induced loads, including linear and nonlinear methods, multi-body interactions, slamming, green water, sloshing and rogue waves, cables and risers, vortex-induced vibrations, ice loads, fatigue loading and, verification and validation
Hydrodynamic behaviour of pontoon type very large floating structure, using two- and three-dimensional methods
No full textThe influence of nonlinearities on wave-induced motions and loads predicted by two-dimensional hydroelasticity analysis
No full textA two-dimensional hydroelasticity analysis for the symmetric (i.e. vertical motions and distortions) dynamic behavior of ships in waves, including the influence of nonlinearities, is presented in this paper using two methods based on direct integration and convolution integration methods. The influence/ importance of flare slamming, bottom impact and green water, nonlinear hydrodynamic forces due to changes in added mass and damping coefficients as well as restoring and incident wave forces are investigated. The method is illustrated for the S-175 containership. Comparisons made between predictions and experimental measurements indicate good overall agreement. The comparisons also show that the influence of flare slamming is important for the range of speeds and wave amplitudes investigated
Hydroelastic responses of pontoon and semi-submersible types of very large floating structure in regular head waves
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