Extreme Value Statistics of Large Container Ship Roll

2016 ◽  
Vol 60 (02) ◽  
pp. 92-100
Author(s):  
Oleg Gaidai ◽  
Gaute Storhaug ◽  
Arvid Naess

The paper describes a method for prediction of large container ship extreme roll angles occurring during sailing in harsh weather. Rolling is coupled with other ship motions and exhibits highly nonlinear behavior. Risk of losing containers due to a large roll is primary concern for ship transport. Because of non-stationarity and complicated nonlinearities of both waves and ship motions, it is a considerable challenge to model such a phenomenon. In case of extreme motions, the role of nonlinearities dramatically increases, activating effects of second and higher order. Moreover, laboratory tests may also be questioned because of the scaling and the sea state choice. Therefore, data measured on actual ships during their voyages in harsh weather provide a unique insight into statistics of ship motions. The aim of this work is to benchmark state of art method, which makes it possible to extract the necessary information about the extreme response from onboard measured time histories. The method proposed in this paper opens up the possibility to predict simply and efficiently both short- and long-term extreme response statistics.

2016 ◽  
Vol 60 (2) ◽  
pp. 92-100 ◽  
Author(s):  
Oleg Gaidai ◽  
Gaute Storhaug ◽  
Arvid Naess

Author(s):  
Changhong Hu ◽  
Makoto Sueyoshi ◽  
Ryuji Miyake ◽  
Tingyao Zhu

A Cartesian grid method with CIP (Constraint Interpolation Profile [1]) based flow solver has been developed and applied to many strongly nonlinear free surface problems. In this paper we present a research on applying the method to predict nonlinear wave loads on a container ship, which is advancing at a constant forward speed in regular waves with large amplitudes. Numerical computations are carried out on a head sea case and a bow sea case. The computed frequency response characteristics for the ship motions and the wave loads including vertical bending moments on the cross-sections and hydrodynamic pressures on the hull, are compared to a model test result and the result obtained by two potential flow based numerical methods. The nonlinear features of the numerical results are discussed.


2012 ◽  
Vol 81 (6) ◽  
pp. 485-488
Author(s):  
Masanobu TOYODA ◽  
Tsunehisa HANDA

2020 ◽  
Vol 64 (01) ◽  
pp. 61-80
Author(s):  
Ping-Chen Wu ◽  
Md. Alfaz Hossain ◽  
Naoki Kawakami ◽  
Kento Tamaki ◽  
Htike Aung Kyaw ◽  
...  

Ship motion responses and added resistance in waves have been predicted by a wide variety of computational tools. However, validation of the computational flow field still remains a challenge. In the previous study, the flow field around the Korea Research Institute for Ships and Ocean Engineering (KRISO) Very Large Crude-oil Carrier 2 tanker model with and without propeller condition and without rudder condition was measured by the authors, as well as the resistance and self-propulsion tests in waves. In this study, the KRISO container ship model appended with a rudder was used for the higher Froude number .26 and smaller block coefficient .65. The experiments were conducted in the Osaka University towing tank using a 3.2-m-long ship model for resistance and self-propulsion tests in waves. Viscous flow simulation was performed by using CFDShip-Iowa. The wave conditions proposed in Computational Fluid Dynamics (CFD) Workshop 2015 were considered, i.e., the wave-ship length ratio λ/L = .65, .85, 1.15, 1.37, 1.95, and calm water. The objective of this study was to validate CFD results by Experimental Fluid Dynamics (EFD) data for ship vertical motions, added resistance, and wake flow field. The detailed flow field for nominal wake and self-propulsion condition will be analyzed for λ/L = .65, 1.15, 1.37, and calm water. Furthermore, bilge vortex movement and boundary layer development on propeller plane, propeller thrust, and wake factor oscillation in waves will be studied.


2022 ◽  
Vol 243 ◽  
pp. 110335
Author(s):  
Ying Tang ◽  
Shi-Li Sun ◽  
Rui-Song Yang ◽  
Hui-Long Ren ◽  
Xin Zhao ◽  
...  

Author(s):  
Mehrdad Kimiaei

Steel Catenary Risers (SCRs) are one of the main components in development of oil and gas fields in deep waters. Fatigue design of SCRs in touch down zone (TDZ) is one of the main engineering challenges in design of riser systems. Nonlinear riser-soil interaction models have recently been introduced and used widely in advanced structural analysis of SCRs. Due to hysteretic nonlinear behavior of the soil, SCR system will show different structural response under different loading time histories. This paper investigates the effects of nonlinear riser-soil interaction in the TDZ on fatigue performance of an example SCR subjected to randomly generated waves. Sensitivity of fatigue life of the system, location of the critical node and the maximum stress range to different wave realizations and different soil types are discussed in detail.


2020 ◽  
Author(s):  
◽  
Ante Džolan

Concrete is a material with highly nonlinear behavior. In parallel, there are numerous secondary effects in concrete, such as aging, shrinkage, and creep, which further complicate the realistic simulation of reinforced concrete and prestressed concrete structures. In modern times, due to bolder construction, increasing spans and high rising construction, the need for realistic simulation of the behavior of concrete structures under conditions of various types of loads is becoming more pronounced. On the other hand, models with a small number of real-life parameters that can describe the actual behavior of concrete as accurately as possible are necessary. One such model, the previously developed model Precon 3D, which is based on a small number of parameters and can very well describe the behavior of concrete, reinforced concrete and prestressed structures for short-term static loads was taken as the basis for this work. Through this work, the numerical model Precon 3D has been upgraded with a model for following the behavior of concrete during time, i.e. the model has been upgraded with a model of creep and shrinkage of concrete, which is necessary for following the behavior of prestressed structures. The developed software has been tested against several experimental examples from the literature, with a very good match between numerical and experimental results.


2014 ◽  
Author(s):  
K Ouchi ◽  
◽  
Y Tanaka ◽  
A Taniguchi ◽  
J Takashina ◽  
...  

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