Quasi-Static Flooding Analysis Method of a Damaged Ship Considering Oil Spill and Cargo Load

2022 ◽  
pp. 1-21
Author(s):  
Ki-Su Kim ◽  
Myung-Il Roh ◽  
Seung-Min Lee
Keyword(s):  
Equilibrium Position ◽  
Pressure Effect ◽  
Design Stage ◽  
Analysis Method ◽  
Final State ◽  
Damage Stability ◽  
The Time Domain ◽  
Reference Pressure ◽  
Spilled Oil ◽  
Damaged Ship

When a ship is damaged at sea, it is important to predict its behavior as well as whether it is to sink or not. If the ship comes to an equilibrium, the equilibrium position and time should be estimated; otherwise, the time to sink should be estimated. Furthermore, flooding analysis should be carried out not only during the design stage of the ship for preventive reasons, but also after an accident for a better investigation of its causes. In addition, flooding analysis methods that can provide predictions in case of an accident are of particular importance, as there is no time for the required calculations in an emergency. For this purpose, a quasi-static flooding analysis method for the damaged ship in the time domain is proposed in this study. There are a number of studies in which the equilibrium position and time were estimated by flooding analysis. However, most of them have not considered the air pressure effect in fully flooded compartments, and the method of determining the fluid volume in these compartments was not accurate. In the present study, the virtual vent and accumulator method are used to calculate the reference pressure in the fully flooded compartments, and the compartment shape is considered by using polyhedral integration. Also, spilled oil and solid cargo items from the damaged ship are taken into account for realistic flooding analysis. Finally, the damage stability criteria were checked not only in the final state, but also during the entire time of the flooding, as the intermediate states can be more hazardous than the final state. To validate the feasibility of the proposed method, it was applied to a naval ship, which is considerably more stringent for damage stability. As a result, we checked the availability of this study.

An Analytical Approach to Functional Design

2002 ◽  
Author(s):  
Kai-Lu Wang ◽  
Yan Jin
Keyword(s):  
Design Stage ◽  
Application Software ◽  
Functional Design ◽  
Functional Dependencies ◽  
Analysis Method ◽  
Modeling And Analysis ◽  
Early Design Stage ◽  
And Function ◽  
Selected Functions ◽  
Function Structures

Functional design is a process in engineering design that dominates the key features of the result to be developed. Designing good functions that both satisfies the requirements and leads to better results is a challenge due to uncertainties on the consequences of the selected functions, and the lack of analysis methods for identifying the properties of function structures. Therefore, extensive experiences are usually required for functional design. This research argues that the physical relationships among the resulting components of a design are the consequences of functional dependencies developed during the functional design process. Therefore based on the understanding of functions and functional dependencies, a reasoning procedure can be developed to predict the performance properties of the design so that the effectiveness of the functional design can be evaluated at an early design stage. This paper proposes a dependency-based function modeling and analysis method that can be applied to represent and assess functions and function structures at the functional design stage. Designers can predict the properties of the functions they designed without having to have similar design experiences. An application software is also developed to implement the method and demonstrate its effectiveness.

Structural Reliability of Oil Tanker in the Adriatic Sea Damaged in Collision and Exposed to Combined Bending Moments

2018 ◽  
Author(s):  
Maro Ćorak ◽  
Joško Parunov
Keyword(s):  
Structural Reliability ◽  
Adriatic Sea ◽  
Bending Moment ◽  
State Function ◽  
Regression Equations ◽  
Bending Moments ◽  
Damage Stability ◽  
Safety Indices ◽  
Oil Tanker ◽  
Damaged Ship

The aim of the paper is the assessment of structural reliability of oil tanker which may be damaged in collision accident in the Adriatic Sea and exposed to combined, horizontal and vertical bending moments. Damage size is assumed based on the direct numerical simulation of the ship-ship collision. This is justified for some specific sea environments, as the Adriatic Sea, where ship sailing routes and representative ship types involved in accidents are known, so possible collision scenarios may be reasonably predicted. Residual bending moment capacity under combined bending moment is calculated using regression equations developed based on non-linear finite element analysis. Still water vertical bending moments are obtained by damage stability analysis. Vertical and horizontal wave bending moments are determined by short-term response analysis of damaged ship in the Adriatic Sea, using transfer functions obtained by 3D panel hydrodynamic method. Limit state function is defined using interaction equation for damaged ship exposed to combined bending moments. Safety indices are calculated by FORM for different collision scenarios that are generated by MC simulations. Such approach enables to determine the safety indices for the most frequent damages and also to reveal the most critical situations resulting in the lowest safety indices.

Modelling of Systems with Elements in Several States

2021 ◽  
Vol 17 ◽  
pp. 244-252
Author(s):  
Anna Tarasenko ◽  
Oleksandr Karelin ◽  
Manuel Gonzalez Hernández ◽  
Oleksandr Barabash
Keyword(s):  
Mortality Rate ◽  
Integral Equations ◽  
Equilibrium Position ◽  
Mutual Influence ◽  
Initial State ◽  
Final State ◽  
And Shifts ◽  
Cyclic Models

In this paper, we consider systems with one resource, which can be in several states. The states differ significantly in their processes of mortality, reproduction and mutual influence. For instance, infected elements can have a higher mortality rate than healthy and recovered ones. For cyclic models, in which the initial state of the system coincides with the final state, balance relations are found. They represent a system with functional operators with shift and integrals with degenerate kernels. Modified Fredholm method, proposed in previous works to solve the integral equations of the second type with degenerate kernels and shifts, is applied. Equilibrium position of a system with a three-state resource is found.

scholarly journals A Method for the Analysis of Interference from DME to ATCRBS in the Time Domain

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 393 ◽  
Author(s):  
Guofeng Jiang ◽  
Yangyu Fan ◽  
Hongbo Yuan ◽  
Pengliang Yuan
Keyword(s):  
Time Domain ◽  
Traffic Control ◽  
Initial Time ◽  
Analysis Method ◽  
Operating Modes ◽  
The Monte Carlo Method ◽  
The Difference ◽  
The Time Domain ◽  
Overlap Method ◽  
Recurrence Frequency

Analysis of the coexistence of two or more types of equipment is increasingly important. However, at present studies on the analysis method in the time domain are scant. Therefore, the aim of this paper is to explore the characteristics of signals and relations between interfering and desired signals in the time domain. Based on the periodicity of a signal, this paper presents a Periodic Pulse Overlap Method (PPOM). Using PPOM to analyze the interference from Distance Measuring Equipment (DME) to Air Traffic Control Radar Beacon System (ATCRBS) in the time domain, we obtain almost the same result as that based on the Monte Carlo Method (MCM). Furthermore, we discover the measures to reduce or even avoid interference, such as changing the Pulse Recurrence Frequency (PRF), adjusting the difference of initial time, and switching the operating modes of the equipment.

Semi-Submersible Floater’s VIM Simulation Method for Mooring Line Safety Assessment

2018 ◽  
Author(s):  
Toshifumi Fujiwara
Keyword(s):  
Safety Assessment ◽  
Simulation Method ◽  
Oscillator Model ◽  
Design Stage ◽  
Mooring Line ◽  
Floating Structure ◽  
Mooring Lines ◽  
Wake Oscillator Model ◽  
Wake Oscillator ◽  
The Time Domain

The author proposed the Vortex-induced Motion (VIM) simulation method of a semi-submersible type offshore floating structure using the wake oscillator model based on the potential theory and model test data. This method is easy to use for the time-domain simulation of the VIM amplitude, that is in-line, transverse and yaw motions, of the semi-submersible floater in case of being demented mooring safety assessment of that. The simulation method presented in this paper was modified the single circular floater simulation method with the wake oscillator model for a semi-submersible floater. Some empirical parameters, obtained from the systematic model tests used many semi-submersible floaters, are only decided from external form of the semi-submersible floaters, that is the column / lower hull ratio etc. This simulation method is able to indicate general VIM trend and to be used for the assessment of mooring lines safety in the design stage. Using the VIM amplitude simulation, fatigue damage of mooring lines on one sample semi-submersible floater was investigated as an example.

A Collaborative Rapid Analysis Method for Decision-Making in Assembly Line Design

2004 ◽  
Author(s):  
Masataka Yoshimura ◽  
Satoshi Yoshida ◽  
Yoshinori Konishi ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki ◽  
...  
Keyword(s):  
Decision Making ◽  
Conceptual Design ◽  
Assembly Line ◽  
Rapid Analysis ◽  
Design Stage ◽  
Analysis Method ◽  
Design Engineers ◽  
Volume Flexibility ◽  
Conceptual Design Stage ◽  
Line Design

Many highly accurate computer simulation tools have been developed for assembly line design, such as for simulation of assembly processes, but these tools require much input information and are generally utilized only in detailed design stages. This paper proposes a rapid analysis method for manual assembly line design, which can be utilized in the conceptual design stage. This method is based on a layout tool where design engineers can construct assembly line models using 2- and 3-D views. This method provides design evaluation techniques for multiple important criteria such as volume flexibility, visibility, and so on, using the layout data. Spatial evaluation and quantitative efficiency analyses can be simultaneously performed, which enhance collaborative decision-making in the conceptual design stage.

Dynamic Stability of FPSO-Shuttle Systems: An Analytical Procedure and Practical Results

2002 ◽  
Author(s):  
Ge´rson B. Matter ◽  
Joel S. Sales ◽  
Sergio H. Sphaier
Keyword(s):  
Dynamic Stability ◽  
Deep Water ◽  
Dynamic Systems ◽  
Time Domain ◽  
Equilibrium Position ◽  
Analytical Procedure ◽  
Time Domain Analysis ◽  
The Stability ◽  
The Time Domain ◽  
Floating Systems

The paper deals with the dynamics of floating systems (FPSO units) moored in deep water in the presence of currents. The offloading operation is carried out in a tandem arrangement from the FPSO to a Shuttle ship of lesser capacity. According to the classical theory of dynamic systems, a study of the behavior of floating units is performed by determining the equilibrium position and then analyzing the stability around this position. The time domain analysis is also used to compare the results. This procedure is extended to the case of systems in a spread mooring configuration and with turret.

Stability Evaluations of Semi-Submersible Heavy Transport Vessels by a Progressive Flooding Simulation Tool

2012 ◽  
Author(s):  
Hendrik Dankowski ◽  
Hannes Hatecke
Keyword(s):  
Time Domain ◽  
Simulation Method ◽  
Intermediate Step ◽  
Viscous Effects ◽  
The Past ◽  
Discharge Coefficients ◽  
Damage Stability ◽  
Offshore Industry ◽  
The Stability ◽  
The Time Domain

Rising needs for heavy transport operations are intensified by the expanding offshore industry worldwide. Whenever very large and heavy objects have to be transported, only semi-submersible heavy transport vessels are capable of carrying this special cargo. Accidents in the past during operations of these vessels highlight the requirement of analyzing the operation procedures in more detail. Especially the submerging process of the main working deck is very critical regarding the hydrostatic stability. A new numerical progressive flooding simulation method will be presented for applications like accident investigations or damage stability assessments. This method is modified to fit the special requirements of simulating the operational behavior of semi-submersible vessels in the time-domain. A direct approach is chosen, which computes the flux between the compartments based on the Bernoulli equation and the current pressure heads at each intermediate step. Losses due to viscous effects are taken into account by empirical discharge coefficients. This method will be used to simulate the submerging operation in the time-domain to point out critical situations regarding the stability of the vessels and the cargo. This will be compared to accidents which occurred in the past. Furthermore, recommendations for operational procedures are proposed.

Signal Acquisition and Analysis of Shaft Unbalance Vibration Test

2014 ◽  
Vol 945-949 ◽  
pp. 1090-1093
Author(s):  
Hai Peng Zhang ◽  
Hong Wu Chen ◽  
Bin Hu ◽  
Cheng Tian
Keyword(s):  
Fault Diagnosis ◽  
Time Domain ◽  
Time Domain Analysis ◽  
Rotating Machinery ◽  
Vibration Test ◽  
Signal Acquisition ◽  
Analysis Method ◽  
Characteristic Parameters ◽  
Test Platform ◽  
The Time Domain

This paper simulated the unbalance vibration conditions by the vibration test platform, measuring some common characteristic parameters of unbalance vibration fault diagnosis. This paper chose the time-domain analysis method, processing the characteristic parameters of the test, so as to achieve the purpose of vibration diagnosis. Through a large number of experimental data, this paper verified the feasibility and the effectiveness of the proposed approach to the unbalance fault diagnosis. The method proposed in this paper not only can be applied to unbalance fault diagnosis, but also can be promoted to apply to the fault diagnosis of other rotating machinery.

Estimation of Direction of Wavefront Propagation and Slowness Using Time Domain Wavenumber Analysis in Small-Size Dense Seismic Arrays

2012 ◽  
Vol 479-481 ◽  
pp. 1186-1189
Author(s):  
Ping Liu ◽  
Hua Ma ◽  
Xue Wei Zhang ◽  
Xin Yu Sun ◽  
Fei Cao
Keyword(s):  
Time Domain ◽  
Seismic Array ◽  
Apparent Velocity ◽  
Seismic Signals ◽  
Analysis Method ◽  
Seismic Arrays ◽  
Wavefront Propagation ◽  
Pass Through ◽  
The Time Domain ◽  
Dense Seismic Array

The time domain wavenumber analysis method can directly delay and align signals before the superposition of signals in the time domain. In this paper, estimating the direction of wavefront propagation and the slowness for seismic signals which pass through the small-size dense seismic array is described in detail. The earthquake recorder sample adopted from US Geological Survey Parkfield Dense Seismograph Array (UPSAR array) of the U.S is used for analyzing. The results indicate that, the direction of wavefront propagation cannot be determined rashly only by the connecting line of the earthquake epicenter to the seismic array. The accuracy of the apparent velocity and the direction of wavefront propagation calculated using vertical seismic recorders is higher in West-East direction and in North-South direction.

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