Stochastic procedures for extreme wave load predictions – Wave bending moment in ships

Jensen, Jørgen Juncher

doi:10.1016/j.marstruc.2008.08.001

Cited by 38 publications

(15 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, instead of the simplified model where the ship plunges in a deterministic manner in a plane water surface or the other extreme of a full time simulation of the vessel in a stochastic sea, we shall in this section apply a more realistic wave sequence situation which can be used to identify the most probable extreme whipping loads. This socalled critical wave episode, or most likely response wave, described by Jensen, 27 represents the most likely mean wave and ship motion associated with a given extreme wave hull girder bending moment response.…”

Section: Slamming Event In a Conditional Wavementioning

confidence: 99%

“…The critical wave episode calculation by Jensen 27 was based on a time-domain non-linear strip theory calculation procedure described by Xia et al, 28 linked to a first-order reliability method (FORM) code. The hull is assumed to be rigid in the present study but the work by Jensen 27 also contained similar results for a flexible hull.…”

Section: Slamming Event In a Conditional Wavementioning

confidence: 99%

See 1 more Smart Citation

Numerical prediction of slamming loads

Seng

Jensen

Pedersen

2012

Proceedings of the Institution of Mechanical Engineers, Part M:

View full text Add to dashboard Cite

It is important to include the contribution of the slamming-induced response in the structural design of large vessels with a significant bow flare. At the same time it is a challenge to develop rational tools to determine the slamming-induced loads and the prediction of their occurrence. Today it is normal practice to apply a standard sea-keeping procedure to determine the relative velocity distribution between the water surface and the hull and then to estimate the bottom slamming loads and the bow-flare slamming loads based on two-dimensional formulations similarly to water-entry problems. The pressure distribution as well as the total force is then determined by integration over a pseudo-threedimensional presentation of the hull geometry.In this paper the evaluation of the slamming load is taken one step further by performing direct three-dimensional, fully non-linear numerical calculations in a realistic wave environment.Both the global and the local slamming loads are assessed numerically using a finite-volume formulation with the free surface captured by a volume-of-fluid technique. This numerical procedure is justified by comprehensive validation studies where numerically evaluated slamming pressures are compared with experimentally measured results.To obtain an insight into the three-dimensional flow effects the next step is to apply the validated numerical procedure to evaluate and compare the accuracy and performance of the traditionally used two-dimensional formulations by a comparison with three-dimensional numerical formulations for a fine-form Panamax container ship bow hitting a flat water surface at a constant trim angle.Finally, the slamming evaluation is carried out on the basis of a three-dimensional case study of the same container ship sailing in a head sea at half the service speed in a critical wave episode which is defined conditional on a given extreme response level of the hull girder bending moment.

show abstract

Section: Slamming Event In a Conditional Wavementioning

confidence: 99%

Section: Slamming Event In a Conditional Wavementioning

confidence: 99%

Numerical prediction of slamming loads

Seng

Jensen

Pedersen

2012

Proceedings of the Institution of Mechanical Engineers, Part M:

View full text Add to dashboard Cite

show abstract

“…A fundamental theory for predicting the extreme values and MPWEs proposed by Jensen [11] is adopted in this study. When one considers linear, long-crested irregular waves, the free-surface elevation can be represented as a superposition of N discrete harmonic wave components:…”

Section: Generalmentioning

confidence: 99%

“…An effectiveness of applying the FORM-based approach to extreme wave-induced vertical bending moment (VBM) prediction was demonstrated by Jensen [10]. Further extension of this work was conducted for evaluating VBM with nonlinearity taken into consideration, i.e., whipping effect of a flexible ship, by leveraging the nonlinear strip theory [11]. An application of the FORM-based approach to extreme value problems of structural responses subjected to combined loads was performed by Iijima et al [12].…”

Section: Introductionmentioning

confidence: 99%

Efficient FORM-based extreme value prediction of nonlinear ship loads with an application of reduced-order model for coupled CFD and FEA

et al. 2019

View full text Add to dashboard Cite

In this paper, a method for predicting the extreme value distribution of the vertical bending moment (VBM) in a ship under a given short-term sea state is presented. To predict the extreme value distribution of the VBM, the first-order reliability method (FORM), by which the most probable wave episodes (MPWEs) leading to given VBMs are identified, is introduced. The coupled computational fluid dynamics (CFD) and finite-element analysis (FEA) are used to provide the high-fidelity numerical solutions for the wave-induced and whipping components of the VBM. Then, a Reduced-Order Model (ROM) which can yield the predictions equivalent to the coupled CFD-FEA results in a relatively short time is developed. The ROM is incorporated into FORM to identify the MPWEs, in lieu of the coupled CFD-FEA. The accuracy of the ROM is verified by comparing with the coupled CFD-FEA results under identified MPWEs, in terms of both the wave-induced and whipping VBM. Then, a series of tank tests using a scaled container ship is conducted. In the first series of the tests, the VBM measurements under the MPWEs identified from the FORM-based approach using the ROM are made, to validate the accuracy of the ROM. The extreme value distribution of the combined wave-induced and whipping VBM is also measured by performing the second series of the tests, in random waves. The validity of the FORM-based extreme value prediction using the ROM is investigated by comparing with the second series of the tests.

show abstract

“…In view of small scale structures, such as isolated pile columns, various pipelines, and seabed risers, the method proposed by Professor Morrison and others at the American University of Berkeley, 1950, is called the Morison method [16].…”

Section: Analysis Of Hydrodynamic Load Of Grouting Clamp On Wave and mentioning

confidence: 99%

Hydrodynamic Load and Parametric Design of Grouted Clamp Used on Offshore Jacket

Zhang

Wang

2018

Polish Maritime Research

View full text Add to dashboard Cite

The reliability and safety of offshore platform are an important research aspect in marine engineering. The jacket platform is mainly used for oil development and submarine drilling, and the long-term work in the marine environment will be subjected to different loads, which will lead to the damage of the structure part of the offshore platform. It affects the structural strength of the platform. For the repair of jacket damage, grouted reinforcement technology is adopted, which has the advantages of simple underwater installation and low cost. The reinforcement technology of the grout hoop has been applied to the engineering projects abroad, but the stress and serialization design of the hoop in the marine environment need further study. This paper will combine the ocean current and wave force to carry out the research of underwater work and prevent loosening, and put forward the parametric design method for the specific size of the hoop. Two types of experimental models are designed: short bolt form clamp and long bolt form clamp. The mechanical experiment of the long bolt clamp is carried out, and the relationship between the slipping force and the bolt preload is analyzed, so as to verify the theoretical analysis.

show abstract

Stochastic procedures for extreme wave load predictions – Wave bending moment in ships

Cited by 38 publications

References 16 publications

Numerical prediction of slamming loads

Numerical prediction of slamming loads

Efficient FORM-based extreme value prediction of nonlinear ship loads with an application of reduced-order model for coupled CFD and FEA

Hydrodynamic Load and Parametric Design of Grouted Clamp Used on Offshore Jacket

Contact Info

Product

Resources

About