Contribution of supposed wave condition on the long-term distribution of a wave-induced load

2002 ◽  
Vol 6 (3) ◽  
pp. 135-147 ◽  
Author(s):  
Hiroshi Kawabe
Keyword(s):  
Wave Condition ◽  
Wave Induced

scholarly journals Contribution of Supposed Wave Condition on Long-term Distribution of Wave Induced Load

2000 ◽  
Vol 2000 (187) ◽  
pp. 253-263
Author(s):  
Hiroshi Kawabe ◽  
Hiroshi Tanaka ◽  
Kouta Shibazaki
Keyword(s):  
Wave Condition ◽  
Wave Induced

scholarly journals Contribution of Supposed Wave Condition on Long-term Distribution of Wave Induced Load

1999 ◽  
Vol 1999 (186) ◽  
pp. 319-339 ◽  
Author(s):  
Hiroshi Kawabe ◽  
Shigeyuki Hibi ◽  
Hiroshi Tanaka ◽  
Kouta Shibazaki ◽  
Hiroshi Sasajima
Keyword(s):  
Wave Condition ◽  
Wave Induced

scholarly journals NUMERICAL MODELING OF SHORELINE EVOLUTION AROUND THE RIVER MOUTH

1984 ◽  
Vol 1 (19) ◽  
pp. 202
Author(s):  
Ming-Chung Lin ◽  
Jyh-Cherng Wang
Keyword(s):  
Numerical Models ◽  
River Sediments ◽  
River Mouth ◽  
Typical Feature ◽  
Wave Condition ◽  
Shoreline Evolution ◽  
Longshore Sediment Transport ◽  
Proposed Model ◽  
Wave Induced

The river sediments transport into coastal water together with wave induced longshore sediment transport make shoreline evolution much complicated. Fig.l shows typical feature of shoreline shape around a river mouth. Recently there are some investigators treated this problem (Grijm, 1964, Bakker §Edelmen,1964; Komar,1973; Tsuchiya § Yasuda,1978),and had developed some mathematical or numerical models. This paper proposes a numerical model for predicting long-term shoreline evolution around a river mouth by incorporation certain river parameters into the Willis beach evolution model (1978). The proposed model is at first applied to four ideal cases to investigate its general characteristics and adaptability, and reasonable results are found. In our results the accretion on updrift side is faster than downdrift side under the oblique incident wave condition and the width of the river mouth increase steadily. These results are different from other approachs that the shoreline shape is always nearly symmetrical with respect to the centerline of the river mouth. Finally, as an field case application of the model, a numerical simulation of shoneline changes around the Cho-shui River mouth is performed and compared with field data.

Load Combination for Fatigue Analysis of Ship Structures

2004 ◽  
Author(s):  
Yung S. Shin ◽  
Booki Kim ◽  
Alexander J. Fyfe
Keyword(s):  
Bending Moment ◽  
Linear Summation ◽  
Load Combination ◽  
Longitudinal Stiffeners ◽  
Stress Components ◽  
Tank Pressure ◽  
Wave Induced ◽  
Vertical Bending Moment ◽  
Oil Tanker

A methodology for calculating the correlation factors to combine the long-term dynamic stress components of ship structure from various loads in seas is presented. The methodology is based on a theory of a stationary ergodic narrow-banded Gaussian process. The total combined stress in short-tem sea states is expressed by linear summation of the component stresses with the corresponding combination factors. This expression is proven to be mathematically exact when applied to a single random sea. The long-term total stress is similarly expressed by linear summation of component stresses with appropriate combination factors. The stress components considered here are due to wave-induced vertical bending moment, wave-induced horizontal bending moment, external wave pressure and internal tank pressure. For application, the stress combination factors are calculated for longitudinal stiffeners in cargo and ballast tanks of a crude oil tanker at midship section. It is found that the combination factors strongly depend on wave heading and period in the short-term sea states. It is also found that the combination factors are not sensitive to the selected probability of exceedance level of the stress in the long-term sense.

Analysis of Ship Structural Loading in a Seaway

1972 ◽  
Vol 9 (02) ◽  
pp. 173-194
Author(s):  
Dan Hoffman
Keyword(s):  
Pressure Distribution ◽  
Phase Relationship ◽  
Bending Moment ◽  
Green Water ◽  
Detailed Structural Analysis ◽  
Transverse Pressure ◽  
Structural Loading ◽  
Wave Induced

The recent advent of the large tanker and bulk carrier has promoted the requirements for more detailed structural analysis of a ship and the reevaluation of theories for calculating the static, quasistatic and dynamic loads. The paper begins with discussion of the methods available to determine the various types of loads expected, their phase relationship, and ways of superimposing them. It then proceeds to the treatment of sea loads based on theoretical and experimental data, and techniques of determining the ship response in a seaway are discussed. The response to regular waves is reviewed with special reference to the determination of pressure distribution on the hull. Statistical ship response, immediate and cumulative over the life of the ship, is demonstrated in relation to the prediction of long-term bending moment trends, and the distribution of the extremes is discussed. Special loading conditions are described with special emphasis on the transverse pressure distribution, dynamic effects due to motion of liquid cargo in tanks, shipping of green water, wave-induced vibrations, slamming pressures and whipping stresses due to various causes. The paper treats the above subjects in a broad manner and no attempt to illustrate the theory in detail is made.

Abnormal Wave-Induced Load Effects in Ship Structures

2008 ◽  
Vol 52 (01) ◽  
pp. 30-44 ◽  
Author(s):  
C. Guedes Soares ◽  
N. Fonseca ◽  
R. Pascoal
Keyword(s):  
Extreme Values ◽  
Time History ◽  
Design Criterion ◽  
Freak Waves ◽  
Reference Design ◽  
Load Effects ◽  
Central North Sea ◽  
Wave Induced ◽  
First Time

The paper presents an approach to determine the global load effects induced on shif structures by abnormal, freak, or episodic waves. It refers to the present procedure of determining extreme values of wave-induced responses, including the recent advances of adopting time series of wave elevation as reference design conditions t calculate the wave-induced structural loads on ships in heavy weather. It is show how this procedure can be extended to account for abnormal or episodic waves Reference is made to what is presently known about abnormal or freak waves showing that although it is possible to determine the loads induced by these wave in floating and fixed structures, the present knowledge about the probability of occurrence of these waves is not enough to allow a wave design criterion to be defined in a way consistent with the present probabilistic approaches. However, it is suggested that at the present stage of knowledge it is possible to determine the load induced by abnormal waves similar to ones that have been measured at various ocean locations and that are thus realistic; a method is described to perform such calculations. Although this information cannot replace the wave-induced loads calculated with the presently established procedures, it can serve as guidance for th design. An application example is presented of a containership subjected to a wav trace that includes an episodic wave that was measured during a severe storm in Central North Sea. The measured wave time history is modified in order to investigate the influence of the wave steepness on the induced vertical motions and loads. Th loads induced by the abnormal wave are compared for the first time with extreme values from long-term distributions.

Numerical Analysis of Ship Wave Loads and Structure Strengthen Analysis on a Wind Power Installation Ship

2011 ◽  
Vol 90-93 ◽  
pp. 2521-2527
Author(s):  
Gang Qiang Li ◽  
Yan Yan Zhao ◽  
Yong He Xie
Keyword(s):  
Wind Power ◽  
Structural Design ◽  
Three Dimensional ◽  
Load Condition ◽  
Wave Loads ◽  
Element Simulation ◽  
Wind Power Installation ◽  
Wave Induced ◽  
Term Response

In a typical load condition of wind power equipment Installation ship, using the three-dimensional potential flow theory to prediction the long-term response of wave induced loads. then using the main load control parameters as a basis for the design wave selection, then application of DNV's SESTRA program make the wave-induced directly to the structure to finite element simulation. The results show that the hull structural design can meet the requirements.

Effects of Weather Routing on Maximum Vertical Bending Moment in a Ship Taking Account of Wave-Induced Vibrations

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Kazuhiro Iijima ◽  
Rika Ueda ◽  
Hitoi Tamaru ◽  
Masahiko Fujikubo
Keyword(s):  
North Atlantic Ocean ◽  
Meteorological Data ◽  
Bending Moment ◽  
Simulation Method ◽  
Extreme Value ◽  
Operational Parameters ◽  
Wave Condition ◽  
Weather Routing ◽  
Wave Induced ◽  
Vertical Bending Moment

In this paper, the effect of weather routing and ship operations on the extreme vertical bending moment (VBM) in a 6000TEU class large container ship which is operated in North Atlantic Ocean is addressed. A direct time-domain nonlinear response simulation method taking account of the wave-induced vibrations is combined with a voyage simulation based on 10 years of meteorological data in the area. The probability distribution of the ship's operational parameters conditional upon the meteorological conditions is considered. It is clarified that the most severe wave condition with the significant wave height over 16 m in the area may not be encountered by the ship due to the weather routing and the extreme value is determined mostly by the wave condition much milder than the most severe in the area. It is also found out that the ship speed assumed in the most contributing sea state strongly affects the extreme value of the total VBM. It is explained by the fact that the wave-induced vibrations in the ship tend to be excited at faster speed.

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