Dissertations / Theses on the topic 'Preliminary ship design'

Alongside deploying weapons and sensors what makes a warship distinct is survivability, being the measure that enables a warship to survive in a militarily hostile environment. The rising cost of warship procurement, coupled with declining defence budgets, has led to a reduction in the number of ships in most western navies. Moreover, cost cutting is often aimed at aspects which may be difficult to quantify, such as survivability, and can lead to potentially inadequate designs. Innovation in both the design process and the design of individual ships is, therefore, necessary, especially at the crucial early design stages. Computer technology can be utilised to exploit architecturally orientated preliminary design approaches which can address innovation early in the ship design process and in issues such as survivability. A number of survivability assessment tools currently exist; however, most fail to integrate all survivability constituents (i.e. susceptibility, vulnerability and recoverability), in that they are unable to balance between the component aspects of survivability. Some are qualitative, therefore less than ideal for requirement specification, others are aimed towards the detailed design stages where implementing changes is heavily constrained or even impractical. Since a ship’s survivability is dependent on layout, the approach adopted in this research takes advantage of an architecturally orientated ship design approach applicable to early stage design. Such a method is proposed and demonstrated on five combatant (including a trimaran configuration) and two auxiliary ship design studies. The proposed method combines various tools used by UCL and the UK Ministry of Defence, as well as a new approach for recoverability assessment and, therefore, tackles difficulties currently associated with the latter (e.g.: lack of data, human performance and time dependence) by using weighted performance measures. An overall approach for survivability assessment has been applied across the range of designs produced and conclusions drawn on their relative merits for overall survivability. The approach and implications of the integration of survivability assessment in the preliminary ship design stages, as well as the identification of major survivability design drivers, are discussed. Through the identification of problematic topics, areas for further research are suggested. It is envisaged that this research will assist in developing the design process of what are, according to Captain C. Graham, USN, “the most complex, diverse and highly integrated of any engineering systems” produced today on a regular basis.

A practical way to estimate the ship response in early design stage is investigated in this thesis. Focus has been put on the ship vertical bending moment and shear force in operation area. ISSC spectrum is used to indicate the sea state. Napa strip method is employed to derive the transfer function. The ship response is thus generated in frequency domain. The vertical bending moment and shear force along the ship are then calculated according to the critical wave case indicated from the response function. Based on the results, the validation of DNV-GL rule and IACS rule is discussed. In this case, the overestimation is discovered for the still water vertical bending moment and shear force. On the other hand, there is underestimation in wave vertical bending moment and shear force. The total vertical bending moment and shear force is reasonable. Since only static loads and total loads are required in the rules, the rules are judged as valid in the early design stage. The feasibility of Napa strip method has been commented and the Napa strip method is judged practical according to its accuracy and time consumption. For ship design, the wavelength and the wave steepness are the main parameters affecting the loads on hull. The block coefficient is crucial for the nonlinearity in hogging and sagging condition. More models, especially other types of ships are expected to be analysed for this topic in future study. Other methods, such as panel method could take into use in the future work. The probability of operation can be further developed based on this study.

This thesis provides a means to estimate the physical and performance characteristics of a preliminary cruise ship design. The techniques utilized to estimate these characteristics are showcased in the user-friendly interface known as the Cruise Ship Analysis Tool (CSAT). Using the CSAT, the implications that design feature decisions in the preliminary design stage have on a cruise ship’s profitability is analyzed. Then, the most profitable design feature assemblage among a finite number of varying design feature combinations is estimated and compared among cruise ship designs with different passenger carrying capacities. Profitability is analyzed using the measure of merit (MOM) known as net present value (NPV). If a preliminary cruise ship design has a positive NPV at a reliable rate of return and ship operating life, the design is considered to be a profitable investment if implemented. The greater the NPV, the more profitable the investment is considered to be.

Approved for public release; distribution is unlimited
Speed, payload, and range are three primary interconnected variables in preliminary ship design. One design variable cannot be maximized without sacrificing the other(s). The purpose of this work is to analyze those combinations of speed, payload, and range that would give the optimal rate of cargo delivery, or throughput, in a given scenario. A physics based mathematical model is developed to display the inter-relationship among the three primary variables. An optimization program was also developed to determine the optimal throughput for different design combinations. A sensitivity analysis was conducted to find an optimal solution that is least sensitive to changes in parameters other than the primary variables. The methodology developed in this work can be easily applied to a different ship class. The results can lead to a quick exploration of the design space in the preliminary design phase in order to isolate ranges of parameters leading to Pareto optimal sets and can be used to guide further design refinements.

Thesis (Masters Diploma (Mechanical Engineering)) -- Cape Technikon, Cape Town,1996
A need exists whereby the preliminary power requirement of a ship can be rapidly estimated. Because the majority of methods available for this purpose are manual and consist of a number of independent components, they are tedious and time consuming to use. With the advent of the personal computer and its widespread acceptance, it was logical to examine the various components involved to determine their suitability for computerisation and general accuracy. In total eleven hull resistance prediction methods were examined, eight of which were computerised. Model test data of four vessels were used to evaluate these eight programs. The methodproviding the best results was selected to form the core of an integrated Power Prediction program. Factors such as appendage resistance, fouling and hull roughness were examined and appropriate methods selected for inclusion into the integrated program. Various propeller series were examined and evaluated against a variety of examples and model data. Two propeller optimisation programs were written and a general method for determining the optimum characteristics from Kr-KQ polynomials is described. Methods for determining propulsion coefficients were examined and their results compared with those obtained from model tests. The method providing the best overall results was incorporated into the Power Prediction program Added resistance due to sea state was broken down into two components, namely wind and wave resistance. Only the head sea and wind conditions were considered. Various methods for estimating wind resistance were examined and a program developed capable of providing resistance estimates regardless of wind direction. The problem of added resistance due to waves was examined and two programs written around the methods examined. To facilitate prediction estimates, sea state was chosen as the prime function. Wave height is estimated for the appropriate sea state and wind speed in turn from the wave height Actual sea trial data ofa twin screw channel ship is used to determine the overall accuracy ofthe Power Prediction Program

Approved for public release; distribution is unlimited
The VAX/VMS UIS graphics library routines were used in the creation of a menu driven, interactive program which solves basic preliminary ship design problems. The program uses a menu with active mouse and keyboard to select options, enter data, and control program execution. At present, the program solves transverse and longitudinal static stability problems and predicts the effects of shifting weight in three planes. It also calculates the hydrodynamic derivatives for maneuvering performance and predicts the turning circle characteristics of the ship. Provisions for a hardcopy, detailed report are also included. Space has been allocated to include future program modules or user supplied programs.

The unique decision making environment that occurs in ship concept design prevents a full exploration of possible solution styles. However, alternative styles present distinct advantages in certain situations. This is particularly true for different hullform styles which can give significant performance benefits. To fully capitalise upon these alternatives, a comprehensive exploration should occur at the outset of the design process. Current ship design methods have been found to limit the designer’s ability to rapidly explore a large number of radically differing alternatives. This is a consequence of a common requirement for the early selection of design styles. Clearly, some approach able to support the designer in exploring alternative styles early in the design process would offer the designer significant advantages. This thesis begins with the identification of a gap in the design methods currently avail- able to the designer selecting hullform style early in the ship design process. It details a design approach aimed at closing this gap while targeting the early design stages of naval ships. A review of wider engineering design research has highlighted several promising models of design theory, knowledge and technology that could be usefully applied to this problem. Using these models a new Library Based approach has been proposed and developed. This Library Based approach employs decomposition and pre-calculation to create a library of sub-options that can be rapidly examined using a set of initial design requirements to develop a range of possible options. Comparison with a notional optimisation process suggests the proposed approach offers advantages for problems similar in characteristic to the selection of hullform style. The approach is then demonstrated through two example implementations which are applied to the initial design of several naval combatants including an existing design. The discussion on the proposed approach highlights its strengths and weaknesses compared to two lists of needs for ship concept design tools and also its potential to be employed in concert with other design methods, aiding the necessary decision-making that occurs early in the ship design process. The key conclusion of the research is that the gap in the selection of hullform style can be met through the application of the proposed Library Based approach. Finally, five areas of future research are recommended: exploring extensions of the approach presented able to extrapolate the contents of the library; extend the approach to provide insight into relationships and drivers; investigating alternative technologies for the library; applying parametric design tools to generate library data; and demonstrating links to other design methods.

This paper is an investigation into a quantitative selection process of either a mechanical or electrical system architecture for the transmission of propulsion power in naval combatant vessels. A database of historical naval ship characteristics was statistically analyzed to determine if there were any predominant ship parameters that could be used to predict whether a ship should be designed with a mechanical power transmission system or an electric one. A Principal Component Analysis was performed to determine the minimum number of dimensions required to define the relationship between the propulsion transmission architecture and the independent variables. Combining the results of the statistical analysis and the PCA, neural networks were trained and tested to separately predict the transmission architecture or the installed electrical generation capacity of a given class of naval combatant.

The methodology used in analyzing the feasibility of installing direct and indirect intercooling systems on naval gas turbines is presented. The indirect system is comprised of two types of heat exchangers; an air to ethylene glycol, plate fin heat exchanger, and an ethylene glycol to seawater shell and tube heat exchanger. The direct system utilizes an air to seawater shell and tube heat exchanger. The analysis requires, as input, air mass flow rates, compressor efficiencies and pressure ratios. The output, based on given environmental constraints and an assumed overall intercooler effectiveness, provides mass flow rates of seawater and ethylene glycol, heat exchanger effectiveness and size, intermediate fluid temperatures, and air and seawater outlet temperatures. The output provides preliminary data for specific heat exchanger design and pump and piping selections.
Master of Science

Este trabalho apresenta um processo racional para a seleção das dimensões e coeficientes de forma ótimos para um navio petroleiro usando a técnica dos algoritmos genéticos. É proposto um procedimento para balanceamento em função do peso e espaço disponível de carga, determinando sua viabilidade e permitindo balancear navios de peso ou de volume. A elaboração de um procedimento e sua implementação em um programa eficiente é muito importante no dimensionamento preliminar de um navio, assim, esta pesquisa é uma divulgação da técnica dos algoritmos genéticos como uma técnica robusta para o projeto preliminar do navio. Duas funções de mérito são usadas para avaliar cada projeto: custo e vazamento médio de óleo. Estes atributos são conflitantes entre si, isto é, um baixo custo corresponde a um alto vazamento e vice-versa. O vazamento médio de óleo é avaliado com a metodologia probabilística proposta pela INTERTANKO (INTERTANKO, 2002). A avaliação do vazamento médio, através de um adimensional, considera a possibilidade de ocorrência de eventos de encalhes e/ou colisão resultando, respectivamente, em dano ao fundo e ao costado. Para a estimativa do custo são utilizados dois modelos, apresentando-se uma comparação dos seus efeitos nos valores finais das dimensões principais. Além disso, para o procedimento de balanceamento, cinco modelos de peso do casco são testados e analisados os impactos na forma e distribuição da fronteira de Pareto. Um algoritmo genético é implementado para buscar os parâmetros de projeto ótimos e identificar a fronteira não-dominada de Pareto. O algoritmo é testado com quatro funções encontradas na literatura técnica. As funções de teste são convexas, não-convexa, descontínua e uma com quatro restrições funcionais. A implementação mostra resultados similares com os apresentados na literatura. Um navio Suezmax, um Aframax e um Panamax são usados como estudo de casos para comparar os resultados obtidos com o programa implementado. Um objetivo adicional deste trabalho é expor à comunidade naval a utilidade e efetividade dos algoritmos genéticos nos problemas de projeto multiobjetivo. O enfoque desta pesquisa está na metodologia implementada e na sua recomendação para o projeto preliminar de navios.
This paper shows the rational process of selecting the optimal dimensions and forms coefficients of tanker ships using the technique of genetic algorithm. It is proposed a procedure to balance designs in weight and useful space and assesses their feasibility so that weight and volume limited tankers can be balanced. The elaboration of a procedure and its implementation in an efficient program is so important in the preliminary dimension of a ship, so this paper is a divulgation of the genetic algorithm as robust technique for the preliminary ship design. Two objective attributes are used to evaluate each design: Total Cost and Mean Oil Outflow. This attributes are conflicting between them, that is, a low cost correspond a high outflow and vice versa. The Mean Oil Outflow is evaluated with the probabilistic methodology proposed by the INTERTANKO to IMO. The assessment of mean oil outflow, by a non dimensional parameter, supposes the event of grounding and/or collision resulting in bottom and side damage respectively. In estimating the cost two models are used performing a comparison of their effects on the final values of principal dimension. In addition, for the balance procedure, five hull weight models are tested and analyzed the impact on the form and distribution of Pareto frontier. A genetic algorithm is implemented to search the optimal design parameters and identify non-dominated frontier of Pareto. The algorithm is tested with four test functions found in the technical literature. The test functions selected are convex, non convex, discontinuing and one with four restrictions. The implementation shows similar results with those showed in others papers. A Suezmax, an Aframax, and a Panamax ships are used as case study in order to compare the gotten results by the implemented program. One additional goal of this work is to expose to naval community the usefulness and effectiveness of the genetic algorithm in the Multi-Objective design. The emphasis of this paper is on methodology of design implemented and is suggested for preliminary ship design.

This thesis presents the feasibility, advantages and impact on Preliminary Ship Design of an approach to integrate ship configurational design with the modelling and simulation of a range of crewing issues, such as operations and evacuation. Integrating personnel movement simulation into preliminary ship design introduces the assessment of onboard operations at the front-end of the design process, informing the design and enabling improved operability while the design is still amenable to changes. The approach to accomplish this integration is discussed with the aim of informing all parties involved in the design of ships with regard to the main aspects of personnel operability and on board safety. The research was undertaken as part of a three years research project funded by the Engineering and Physical Sciences Research Council (EPSRC) entitled “Guidance on the Design of Ships for Enhanced Escape and Operation”. The project aimed at bringing together the University of Greenwich developed “maritimeEXODUS” personnel movement simulation software and the SURFCON implementation in the PARAMARINE suite of the Design Building Block approach to Preliminary Ship Design, which originated with the UCL Ship Design Research team. The approach and procedural implications of integrating personnel movement simulation into the preliminary ship design process are presented through a series of SURFCON ship design case studies. With the UK Ministry of Defence as the industrial partner to the project, this study on “design for operation” concentrates on naval vessels, which provide excellent examples of complex environments. Design studies, based on the Royal Navy Type 22 Batch III Frigate design, were analysed using PARAMARINE, maritimeEXODUS and bespoke interface software produced by the candidate. Technical aspects of the development of the interface software are discussed from a procedural perspective, focusing on integration and usability issues. The discussion addresses alternative options to visualising the simulation results and how to integrate into a ship design model a minimum level of detail sufficient to conduct simulations able to inform the designer, while retaining the flexibility the design requires in early stages design. The thesis concludes by summarising the opportunities that integrating operational simulation into preliminary ship design opens up for the future practice of ship design, contributing to the debate on the nature of ship design and of Computer Aided Preliminary Ship Design.

碩士
國立成功大學
系統及船舶機電工程學系碩博士班
101
At the beginning of ship design, optimal ship design and optimization of ship performance are the goals to the designers for different requirements, such as the minimum resistance, the minimum cost, the maximum capacity, the optimum seakeeping. At the present, the optimization depends on the experience of the designers or a amount of design data. In this case, due to the lack of theoretical foundation, the optimal design is inaccurate, and it wastes a lot of human resources and time. To solve the above menfioned problem, the main purpose to this research is to use multiobjective particle optimization PSO (MOPSO) and variable complexity modeling to implement the optimization for preliminary design of ship. We develop a system which combins a number of commercial softwares, including SHIPFOLW ,ORCA3D ,and RHINO,to change hull form , calculate the performance and estimate the cost of the ship.We develop different three ways to change model with variables from dimensions to control points.We compare the deformation of the results in two, three and five objective functions in different model changing ways.

碩士
國立海洋大學
系統工程暨造船學系
90
Abstract Combining the real-coded evolutionary algorithm with back- propagation networks for the preliminary prediction of ship design is proposed in this thesis. There are three parts in this thesis are examined and discussed. First part, comparing with performance of global search among Nelder- Mead’s simplex method, binary coded genetic algorithms and real- coded evolutionary algorithms through some multi-modal problems. Their results show that for the searching performance the real-coded evolutionary algorithm is the best method among them.The influences of the parameter in the real-coded evolutionary algorithm on the performance are also studied and discussed. From the studied results, the faster convergent speed and better performance could be easily achieved by using the parameters in the real-coded evolutionary algorithm such as population over 20 and replacing rate about 70% of the population. And then applying the real-code evolutionary algorithm to examine the high-dimensional barnana function, dimensions 100 ~ 200, and compares the test results with those by means of some different methods. The second part in the thesis, three artificial neural networks such as back-propagation network, real-code evolutionary algorithm-network, and hybridized real-coded evolutionary and back-propagation neural network, are examined through nonlinear functions. Comparison of the training performances of neural network shows that the hybridized real- coded evolutionary and back-propagation neural network is the best method among them. Finally, the hybridized real-coded evolutionary and back- propagation neural network approaches is applied to the preliminary prediction for ship design. In this thesis, 29 container ship’s basic design data are collected. The hybridized neural network approach mentioned is used neural network learning and to obtain the better efficiency that the training error for these neural network model is acceptable. Using some different testing data for the learned neural network model, the predicted data approaches to ideal data or actual data closely. In other words, the established neural network model in the thesis for the preliminary prediction for ship design could be successful. Keyword: Nelder-Mead’s simplex method, Genetic Algorithms, Real-coded Evolutionary Algorithm, Artificial Neural network, Back-Propagation Network, Preliminary Prediction for Ship Design

碩士
國立成功大學
造船及船舶機械工程學系碩博士班
90
This paper is based on two-dimension strip theory.The purpose of the present study is to discuss a procedure to evaluate seakeeping performance and operability in rough weather during the preliminary design of cargo ships.The present study goes one step further by estimating the consequences of different seakeeping performance in terms of cost.Formulae are presented to estimate the annual delay and the reduced number of crossings per year due to voluntary speed reduction and course change to escape from hazardous responses.