A Coupled FE-SPH pproach for Simulation of Structural Response to Extreme Wave and Green Water Loading

2008 ◽  
Author(s):  
James Campbell ◽  
Rade Vignjevic ◽  
Minoo Homi Patel
Keyword(s):  
Structural Response ◽  
Green Water ◽  
Extreme Wave ◽  
Water Loading

Green Water Assessment for Marine and Offshore Applications: Structural Response of the ULCS Breakwater

2018 ◽  
Author(s):  
Šime Malenica ◽  
Byung Hyuk Lee ◽  
Nikola Vladimir ◽  
Inno Gatin ◽  
Charles Monroy ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Structural Response ◽  
Green Water ◽  
Floating Body ◽  
Water Loading ◽  
Structure Interaction ◽  
Final Design ◽  
Numerical Tools ◽  
Large Container ◽  
Water Assessment

Green water loading which occurs during the floating body operations in heavy weathers can be very dangerous for the structural integrity of the superstructures and the equipment’s located at the upper decks. The correct modeling of the green water loading and the corresponding structural response is far from trivial and many different physical aspects need to be taken into account at the same time. Depending on the type of the floating body, the overall procedure involves the use of the different numerical tools at different steps. For off-shore type structures the procedure is slightly more complicated than for ships because, in addition to the classical seakeeping simulations, the mooring software also needs to be used. In all cases the final design conditions should be modeled using the complex hydro-structure interaction tools. In the present work the overall methodology is demonstrated and applied to the case of the evaluation of the structural response of the breakwater on the Ultra Large Container Ship (ULCS).

Toward Limit State Design of Ships and Offshore Structures Under Impact Pressure Actions: A State-of-the-Art Review

2006 ◽  
Vol 43 (03) ◽  
pp. 135-145
Author(s):  
Jeom Kee Paik
Keyword(s):  
Limit State ◽  
Structural Response ◽  
Time History ◽  
Rate Sensitivity ◽  
Offshore Structures ◽  
Impact Pressure ◽  
Green Water ◽  
Limit State Design ◽  
Structural Capacity ◽  
Pressure Time

In design of ships and ship-shaped offshore units, issues related to impact pressure actions arising from sloshing, slamming, green water, or explosion are of particular concern. The structural response under impact pressure actions is quite different from that under static or quasistatic actions. It has been recognized that the limit state approach is a more rational basis for structural design and safety assessment where both "demand" (loads) and "capacity" (strength) must be accurately defined. For impact pressure action cases, the demand is associated with hydrodynamics areas, taking into account the characteristics of impact pressure-time history, and the structural capacity is associated with structural mechanics areas, considering geometric and material nonlinearities together with strain rate sensitivity. This paper reviews recent advances and trends toward future limit state design of ships and offshore structures under impact pressure actions.

Effective and Efficient Breakwater Design for Trading Vessels and FPSOs

2006 ◽  
Author(s):  
Kamlesh Varyani ◽  
Trevor Hodgson ◽  
Xuan Pham
Keyword(s):  
Cost Effective ◽  
Green Water ◽  
Design Criteria ◽  
Forward Speed ◽  
Water Loading ◽  
Supporting Structure ◽  
Horizontal Loading ◽  
Double Skin

Breakwaters obviously need to fulfil their function (protecting sensitive structures or cargo) while at the same time remaining intact and imposing manageable loads onto supporting structure. It goes without saying that such breakwaters should be cost effective, so that complex designs with extensive welding may not be preferable. In this paper the authors will discuss green water loading on breakwaters for trading vessels like container ships which have forward speed and FPSOs which have zero speed. Different generic designs of V shape, vane type, double skin with and without holes and forward sloping forecastle (whaleback deck) breakwaters applied to trading vessels will be discussed. Guidelines for modelling green water horizontal loading on breakwaters of FPSOs and trading vessels using CFD techniques will be provided. The paper will also include a review of breakwater design criteria in rules and regulations.

Green Water Loading on a FPSO

2002 ◽  
Vol 124 (2) ◽  
pp. 97-103 ◽  
Author(s):  
O. M. Faltinsen ◽  
M. Greco ◽  
M. Landrini
Keyword(s):  
Nonlinear Effects ◽  
Rigid Wall ◽  
Green Water ◽  
Ship Motions ◽  
Sea Waves ◽  
Coupled Flow ◽  
Local Flow ◽  
Water Loading ◽  
Dam Breaking ◽  
The Impact

Green Water Loading in the bow region of a Floating Production Storage and Offloading unit (FPSO) in head sea waves is studied by numerical means. A 2-D method satisfying the exact nonlinear free-surface conditions within potential-flow theory has been developed as a step towards a fully 3-D method. The flow is assumed 2-D in a plane containing the ship’s centerplane. The method is partly validated by model tests. The importance of environmental conditions, 3-D flow effects, ship motions, and hull parameters are summarized. The wave steepness of the incident waves causes important nonlinear effects. The local flow at the bow is, in general, important to account for. It has become popular to use a dam-breaking model to study the propagation of water on the deck. However, the numerical studies show the importance of accounting for the coupled flow between the deck and outside the ship. When the water is propagating on the deck, a suitable distance from the bow can be found from where shallow-water equations can be used. Impact between green water on deck and a vertical deck-house side in the bow area is studied in details. A similarity solution for impact between a wedge-formed water front and a vertical rigid wall is used. Simplified solutions for an impacting fluid wedge with small and large interior angles are developed, both to support the numerical computations and to provide simpler formulas of practical use. It is demonstrated how the local design of the deck house can reduce the slamming loads. The importance of hydroelasticity during the impact is discussed by using realistic structural dimensions of a deck house. This indicates that hydroelasticity is insignificant. On the contrary, first results from an ongoing experimental investigation document blunt impacts against the deck during the initial stage of water shipping, which deserve a dedicated hydroelastic analysis.

Response of Monopod Platform under Extreme Wave in Malaysian Water

2014 ◽  
Vol 567 ◽  
pp. 295-300 ◽  
Author(s):  
Mohd Affiq Bin Jamaluddin ◽  
Mohd Shahir Liew ◽  
V. John Kurian
Keyword(s):  
Load Condition ◽  
Structural Response ◽  
Environmental Load ◽  
Analysis Method ◽  
Extreme Wave ◽  
Offshore Structure ◽  
Wave Condition ◽  
Environmental Loads

This paper investigated the structural response of an existing monopod platform under extreme wave condition in Malaysian water. The estimation of the response plays an important role in the design of offshore structure. In this investigation, in-place analysis is performed to measure the reliability of monopod structure owing to the extreme environmental load condition in Malaysian water.The response of the structure to the varying conditions of the structure and varying environmental loads directions are analysed using well defined in-place analysis method [1]. In the present analysis, the deflection of the structure is studied for the number of guyed wires supporting the structure and multi-direction of environmental loads applied onto the structure.

Time Histories of Wave-in-Deck Loading on Jacket Decks

2006 ◽  
Author(s):  
Katrine van Raaij ◽  
Ove T. Gudmestad
Keyword(s):  
Time Variation ◽  
Structural Response ◽  
Engineering Practice ◽  
Offshore Platforms ◽  
Wave Loading ◽  
Extreme Wave ◽  
Incoming Wave ◽  
Time Histories ◽  
The Difference

Most researchers agree that wave-in-deck loading is of dynamic nature and that the dynamic effects on the structural response are important. However, there exists no engineering practice for the determination of load time histories for waves hitting the decks of fixed offshore platforms. This applies to both the time variation and the magnitude of the loading. This paper presents the main recommendations for wave-in-deck loading with reference to wave tank experiments of a model of the Statfjord A Condeep platform subjected to extreme wave loading. The recommendations for loading from these tests comprise time variation as well as magnitude. These recommendations are used as a basis to suggest a simplified method to estimate wave-in-deck loading on jacket platform decks, for which, to the difference from Condeep platforms, the wave height amplification due to the interaction between the incoming wave and the structure (Swan et al., 1997) is negligible. The resulting ‘recipe’ for wave-in-deck time histories on North Sea jacket platforms is compared to relevant results previously reported in the literature. The method is categorised as a ‘global’ approach, that is, one uses an effective deck area as opposed to a detailed deck model. The method is suggested to be applicable for analyses where a ‘rough but reasonable’ estimate for wave-in-deck loading is sufficient.

Effective and Efficient Breakwater Design for Trading Vessels and FPSOS

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Kamlesh Varyani ◽  
Trevor Hodgson ◽  
Xuan Pham
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cost Effective ◽  
Green Water ◽  
Design Criteria ◽  
Forward Speed ◽  
Water Loading ◽  
Supporting Structure ◽  
Double Skin ◽  
Computational Fluid Dynamics Cfd

Breakwaters obviously need to fulfill their function (protecting sensitive structures or cargo) while at the same time remaining intact and imposing manageable loads onto supporting structure. It goes without saying that such breakwaters should be cost effective, so that complex designs with extensive welding may not be preferable. In this paper the authors discuss green water loading on breakwaters for trading vessels like container ships which have forward speed and FPSOs which have zero speed. Different generic designs of V shape, vane type, double skin with and without holes, and forward sloping forecastle (whaleback deck) breakwaters applied to trading vessels are discussed. Guidelines for modeling green water horizontal loading on breakwaters of FPSOs and trading vessels using computational fluid dynamics (CFD) techniques are provided. The paper will also include a review of breakwater design criteria in rules and regulations.

Numerical Investigation of the Effect due to Vessel Motion on Green Water Impact on Deck

2017 ◽  
Author(s):  
Ravindra Babu Kudupudi ◽  
Ranadev Datta
Keyword(s):  
Green Water ◽  
Global Motion ◽  
Cfd Model ◽  
Water Impact ◽  
Water Loading ◽  
Motion Effect ◽  
Heading Angle ◽  
Vessel Motion ◽  
Volume Method ◽  
The Impact

The present paper focuses on modeling of green water loading on an oscillating body using CFD. The vessel motion is calculated a priory using time domain panel method code, then green water impact is computed based on that pre-calculated motion. The finite volume method is used to capture the green water impact, however in order to represent the free surface, volume of fluid method is used. A sophisticated dynamic mesh is used to handle the motion of the vessel in fluid domain. Several examples and case studies are considered to validate the present CFD model as well as to check the effect of global motion on green water loading such as effect of steepness and heading angle on green water impact. Results show that due to the motion, the impact loading phenomena changes significantly and there is a significant change in pressure on the deck after considering the motion effect and it deviates considerably with the results obtained from fixed vessel cases.

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