Elsevier

Ocean Engineering

Volume 30, Issue 10, July 2003, Pages 1305-1317
Ocean Engineering

Technical Note
Numerical simulation of ship stability for dynamic environment

https://doi.org/10.1016/S0029-8018(02)00109-9Get rights and content

Abstract

The prediction of ship stability during the early stages of design is very important from the point of vessel’s safety. Out of the six motions of a ship, the critical motion leading to capsize of a vessel is the rolling motion. In the present study, particular attention is paid to the performance of a ship in beam sea. The linear ship response in waves is evaluated using strip theory. Critical condition in the rolling motion of a ship is when it is subjected to synchronous beam waves. In this paper, a nonlinear approach has been tried to predict the roll response of a vessel. Various representations of damping and restoring terms found in the literature are investigated. A parametric investigation is undertaken to identify the effect of a number of key parameters like wave amplitude, wave frequency, metacentric height, etc.

Introduction

Stability against capsizing in heavy seas is one of the fundamental requirements in ship design. Capsizing is related to the extreme motion both of ship and waves. Rolling of a ship in rough environment may be influenced by many factors. They can be divided into three main situations; beam sea, following and quartering sea conditions. In the present study, the problem of ship safety has been studied with regard to the rolling motion of a ship in beam waves.

Bhattacharyya (1978) discussed rolling motion of a ship and the devices for roll damping. Dalzell (1978) discussed about the representation of damping in different nonlinear forms. Odabasi and Vince (1982) concentrated on the roll response of a ship under the action of sudden excitation. They studied the importance of roll damping on the response of a ship. Vassalos et al. (1985) explained stability criteria for semisubmersible stability. Lewis (1988) concentrated on rolling dynamics taking into account the wave and other environmental effects. Witz et al. (1989) investigated the roll response of a semisubmersible model with an inflectional restoring moment. Zborowski and Taylan (1989) studied the small vessel’s roll motion stability reserve for resonance conditions. De Kat and Paulling (1989) investigated motions and capsizing of ships in severe sea conditions. Francescutto (2000) studied the problem of ship safety with regard to the stability and rolling motion of ships in beam waves. Taylan (2000) investigated the effect of nonlinear damping and restoring in ship rolling. Chakrabarti (2001) explained various types of damping associated with rolling. He contributed empirical relationships for the calculation of roll damping.

Section snippets

Formulation of the problem

For the purpose of analysis, only the significant motion pertaining to stability and capsizing, namely roll motion has been considered. This simplification can be justified by the reasoning that the vessel capsize is strongly influenced by the roll motion. In addition, among the three transverse coupled motions, only roll has restoring forces and exhibits strong resonant motions. Hence, roll motion can be considered to be the most important in the stability analysis of a vessel.

The factors that

Results and discussions

For the purpose of analysis of linear and nonlinear rolling motion of ships, two vessels that differ in hydrostatic and stability characteristics have been considered. Fig. 1, Fig. 2 show the body plan and isometric view of a RO–RO ship. Table 1 shows the principal particulars of a RO–RO ship. The stability characteristics of the RO–RO ship, viz. GZ, GM, vanishing angle of stability and area under GZ curve are determined by well known Krylove’s method. Fig. 3 shows the GZ curve obtained based

Conclusions

Analytical methods are formulated for the roll motion of ship. Linear and nonlinear approaches are tried. Solutions are obtained using the fourth order Runge–Kutta method. Three types of possible damping are considered based on the literature survey. The restoring arm curve is represented by quintic polynomial. The result of the present approach very well agrees with the published results. A number of cases have been worked out.

References (11)

There are more references available in the full text version of this article.

Cited by (44)

  • Stochastic dynamic analysis of rolling ship in random wave condition by using finite element method

    2022, Ocean Engineering
    Citation Excerpt :

    Hsieh et al. (1994) and Lin and Yim (1995) adopted a simple model for ship rolling in random seas and analyzed the ship's response characteristics, found that all rolling motion trajectories of the vessel excited by noise that visit the regime near the heteroclinic orbit will eventually lead to capsizing, which has been proven to be suitable for verifying ship safety in random waves. For ship safety analysis, a nonlinear analysis approach was established by Surendran and Venkata Ramana Reddy (2003), and the responses of two types of ships with varying hydrostatic and stability properties were predicted. To investigate the stability of a ship under random excitations, the first passage failure theory was adopted by Wang et al. (2008) and Wang and Tan (2009), whose studies indicate that nonlinear damping has a significant influence on the mean first passage time.

  • Emulation of vessel motion simulators for computationally efficient uncertainty quantification

    2019, Ocean Engineering
    Citation Excerpt :

    Using numerical simulators to represent the behaviour of complex physical systems is central to design and operational decision making in offshore engineering. For example, simulating the hydrodynamic responses of floating facilities is used to assess the motions of spread-moored vessels during squalls (Legerstee et al., 2006), predict the heading and motions of vessels given steady metocean conditions (Milne et al., 2016; Milne and Zed, 2018), model ship stability due to roll motions (Surendran and Reddy, 2003), and understand the hydrodynamics of side-by-side offloading (Zhao et al., 2018). While capable of providing valuable point predictions such simulators would also benefit from a common statistical framework to quantify the simulator's uncertainty to produce statistical predictions.

  • On ship roll resonance frequency

    2016, Ocean Engineering
    Citation Excerpt :

    The mathematical modeling of rolling motion enables performing numerical simulations providing an estimation of a ships response to an exciting moment. The nonlinearity of the response observed as a rapid growth of rolling amplitude, intensifies for frequencies close to the resonant mode of motion which is a subject for researches for a long time (Dusinberre, 1954; Surendran & Reddy, 2002, 2003). One of the most astonishing phenomena emerging in the resonance span of rolling is an amplitude bifurcation which has been studied for a long time (Falzarano and Taz Ul Mulk, 1994; Francescutto and Contento, 1999).

  • Enhancement of rolling energy conversion of a boat using an eccentric rotor revolving in a hula-hoop motion

    2016, Ocean Engineering
    Citation Excerpt :

    In Section 7, the experimental setup, prototype, and experimental results are presented, and finally, in Section 8, several conclusions and comparisons between the simulation and experiments are provided. In previous studies (Neves and Rodriguez, 2006; Surendran and Reddy, 2003; Neves et al., 1999, 2003), dynamic analyses of specific boats (length from boat bottom to metacenter ranging from 2.20 to 2.85 m) have been performed. According to the results, the peak of the rolling frequency spectrum ranged from 0.17 to 0.30 Hz, and the maximal rolling angle ranged from ±5° to ±20°.

View all citing articles on Scopus
View full text