An interactive layout exploration and optimisation method for early stage ship design

This paper presents a novel, highly interactive genetic algorithm-based layout exploration and optimisation method for generating spatial configurations of ships in the early stages of the design process. The method draws upon the principles of design-driven architecturally centred ship design processes by enabling the naval architects to make important decisions in a hybrid design process. The method utilises a genetic algorithm-based optimisation tool to rapidly generate and evaluate a diverse set of general arrangement options. It is approached in stages where each stage comprises two steps (manual and automatic). The new genetic algorithm-based layout optimisation tool is demonstrated by being applied to an Offshore Patrol Vessel test case. The advantages and disadvantages of the proposed tool are discussed, as well as the current limitations of the overall approach and future work

Resistance and wake prediction for early stage ship design

Thesis: S.M. in Naval Architecture and Marine Engineering, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 75-76).Before the detailed design of a new vessel a designer would like to explore the design space to identify an appropriate starting point for the concept design. The base design needs to be done at the preliminary design level with codes that execute fast to completely explore the design space. The intent of this thesis is to produce a preliminary design tool that will allow the designer to predict the total resistance and propeller wake for use in an optimization program, having total propulsive efficiency as an objective function. There exist design tools to predict the total resistance and propeller wake, but none that provide adequate computational times for the preliminary design stage. The tool developed uses a potential flow solution coupled with an integral boundary layer solver to predict the viscous resistance and propeller wake. The wave drag is calculated using a modified linear theory, thus eliminating the need to run fully three-dimensional free surface CFD codes. The tool developed is validated against published Series 60 test data.by Brian Johnson.S.M. in Naval Architecture and Marine Engineerin

Interim Report on S3D/LEAPS Integration

The Naval Surface Warfare Center Carderock Division has created the Leading Edge Architecture for Prototyping Systems, or LEAPS, as the data repository for ship design, and a significant number of the early-stage ship design tools interface directly or through a translator with LEAPS. Separately, the Office of Naval Research has funded Smart Ship Systems Design (S3D), a ship design tool effort that expands the Navy’s toolkit to include simulation and distributed system design among other capabilities. The current project will integrate S3D with LEAPS. This report provides an interim status report on progress for the integration project. The project plan and use case are described, underlying terms are defined and correlated between the two databases, and the initial version of the translator code is described

Development of an early stage ship design tool for rapid modeling in Paramarine

Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 85).In early-stage ship design, it is helpful to perform preliminary design and analysis on many configurations to assist in developing and narrowing the trade space. This process is further complicated with the increasing interest in concepts that are breaks from previous practice, such as Integrated Power System (IPS) designs, which require initial development to go deeper than historically based parametrics can provide. Paramarine is a ship design and analysis tool which can be used in this early-stage design; however, as with many early-stage design tools, the fleshing out of diverse ideas in Paramarine can be time and resource consuming. In an effort to enable a developer to create early-stage designs with depth significant enough to be meaningful but still general enough to allow the level of flexibility in design required in the early stages of development, this project seeks to develop an Early Stage Ship Design Tool (ESSDT). This ESSDT is a novel interface with which a designer can rapidly develop and alter basic, major design components of a ship from a compiled database of components and gain a rendered model for analysis within the naval design tool Paramarine. By making use of many early-stage parametric and developed calculations and leveraging the use of IPS, this ESSDT automates many of the initial ship's estimates and minutia of design. Utilizing both Excel and Paramarine software, the ESSDT rapidly creates a visual model of a basic naval vessel with primary systems and equipment from relatively few initial user inputs while embodying a depth of user-changeable default settings for more complex and non-standard design efforts. Several case studies were run to show the capability and flexibility of the tool, as well as showing how new powering and mechnical systems can affect the parameters of the ship as a system of systems.by Eric J. Thurkins Jr.Nav.E.and S.M

Design for Support in the Initial Design of Naval Combatants

The decline of defence budgets coupled with the escalation of warship procurement costs have significantly contributed to fleet downsizing in most major western navies despite little reduction in overall commitments, resulting in extra capability and reliability required per ship. Moreover, the tendency of governments to focus on short-term strategies and expenditure has meant that those aspects of naval ship design that may be difficult to quantify, such as supportability, are often treated as secondary issues and allocated insufficient attention in Early Stage Design. To tackle this, innovation in both the design process and the development of individual ship designs is necessary, especially at the crucial early design stages. Novelty can be achieved thanks to major developments in computer technology and in adopting an architecturally-orientated approach to early stage ship design. The existing technical solutions aimed at addressing supportability largely depend on highly detailed ship design information, thus fail to enable rational supportability assessments in the Concept Phase. This research therefore aimed at addressing the lack of a quantitative supportability evaluation approach applicable to early stage naval ship design. Utilising Decision Analysis, Effectiveness Analysis, and Analytic Hierarchy Process, the proposed approach tackled the difficulty of quantifying certain aspects of supportability in initial ship design and provided a framework to address the issue of inconsistent and often conflicting preferences of decision makers. Since the ship’s supportability is considered to be significantly affected by its configuration, the proposed approach utilised the advantages of an architecturally-orientated early stage ship design approach and a new concept design tool developed at University College London. The new tool was used to develop concept level designs of a frigate-sized combatant and a number of variations of it, namely configurational rearrangement with enhancement of certain supportably features, and an alternative ship design style. The design cases were then used to demonstrate the proposed evaluation approach. The overall aim of proposing a quantitative supportability evaluation approach applicable to concept naval ship design was achieved, although several issues and limitations emerged during both the development as well as the implementation of the approach. Through identification of the research limitations, areas for future work aimed at improving the proposal have been proposed

A Study into the Validity of the Ship Design Spiral in Early Stage Ship Design

For many years the design spiral has been seen to be a convenient model of an acknowledged complex process. It has virtues particularly in recognising the interactive and, hopefully, converging nature of the process. However many find it unsatisfactory. One early criticism focused on its apparent assumption of a relatively smooth process to a balanced solution implied by most ship concept algorithms. The paper draws on a post-graduate design investigation using the UCL Design Building Block approach, which looked specifically at a nascent naval combatant design and the issues of size associated with “passing decks” and margins. Results from the study are seen to suggest there are distinct regions of cliffs and plateaux in plots of capability against design output, namely ship size and cost. These findings are discussed with regard to the insight they provide into the nature of such ship designs and different ways of representing the ship design process. The paper concludes that the ship design spiral is a misleading and unreliable representation of complex ship design at both the strategic and detailed iterative levels

Design of an Ice-Class Propeller for the MV Yahtse, an Icebreaking, Car and Cargo, RoRo Ferry

During early-stage ship design, a propulsion system must be matched with data from a resistance and propulsion analysis to determine the propulsion power required for the vessel to run at its design speed. Typically, this process is completed within NavCAD; however, NavCAD does not have a method to calculate icebreaking resistance or design a propeller to meet the ice-class criteria stipulated by the International Association of Classification Societies (IACS). This paper displays and discusses Python scripts written to complete the resistance and propulsion analysis, propeller optimization, and propeller structural design meeting IACS criteria for an icebreaking, RoRo car and cargo ferry, the MV Yahtse. This code was designed to complete propeller design for the preliminary design stage of the vessel; however, the code can be modified for any stage of design as well as for use with any icebreaking vessel with principal characteristics that fall within the parameters required for the use of Holtrop and Mennen’s resistance and propulsion analysis method. The Python scripts were proven to be able to generate resistance and propulsion analysis results comparable to the results found from NavCAD as well as design two propellers suitable for the MV Yahtse that pass the criteria imposed by the IACS ice-class regulations

Development of an Early-Stage Design Tool for Rapid of Distributed Ship Service Systems Modelling in Paramarine – A Submarine Case Study

The sophisticated 3D based synthesis that is enabled by the UCL Design Building Block (DBB) approach means the designer can model distributed ship service system(s) (DS3) physical entities to whatever level of detail deemed necessary well beyond the DS3 concept design level. The high flexibility of the Paramarine ship design toolset, particularly the descriptive ability provided by the DBB objects through storing data at different levels of design granularity, enables design exploration to different levels of design hierarchy. However, several drawbacks have been found in implementing such a sophisticated (fully 3-D) modelling tool in Early Stage Ship Design (ESSD). These include the effort to model or create each of the numerous features and placing them individually in the vessel’s configuration. The paper presents the development of an ESSD tool that can rapidly generate a submarine early stage design with significant DS3 definition. That definition is sufficiently descriptive but still general enough to allow the level of flexibility in design exploration required at early design stages. The tool aimed to make the 3D based synthesis execution process as simple as possible so that the designer is able to manipulate the 3D architecture of the vessel and focus on important architecturally driven decision making in ESSD. An ocean going conventionally powered submarine case study was undertaken and demonstrated the capability and the flexibility of the tool

The Network Block Approach Applied to the Initial Design of Submarine Distributed Ship Service Systems

The paper follows on from a recent IJME paper and summarises a new early-stage ship design approach. This is termed the Network Block Approach (NBA) and combines the advantages of the UCL 3D physically based ship synthesis Design Building Block (DBB) approach and the Virginia Tech originated Architecture Flow Optimisation (AFO) method for distributed ship service systems (DS3). The approach has been applied to submarine DS3 design and utilises: a set of novel frameworks; and Qinetiq’s Paramarine CASD suite features. The proposed NBA enables the development of a submarine concept design to different levels of granularities. These range from modelling individual spaces to locating various DS3 components and system routings. The proposed approach also enables the designer to balance the energy demands of a set of distributed systems. This is done by performing a steady-state flow simulation and visualising the complexity of the submarine DS3 in a 3D multiplex network configuration. The potential benefits and limitations from such a 3D based physical and network synthesis are presented. The paper concludes with a discussion of the Network Block Approach comparing it to previous applications of network theory which have been to surface ship design. It concludes that it would be possible to better estimate DS3 weight and space inputs to early-stage submarine design and also enable radical submarine configurations and DS3 options to be reflected in early stage submarine design for better concept exploration and requirement elucidation. Finally, further work on the sensitivity of the approach to designer inputs will be addressed in future papers

Applying Queueing Theory and Architecturally-Oriented Early Stage Ship Design to the Concept of a Vessel Deploying a Fleet of Uninhabited Vehicles

Uninhabited vehicles technology is becoming important in naval warfare, providing an entirely new capability. By projecting power through the deployment of such vehicles, the exposure of humans to military threats is reduced. Although the Royal Navy is pursuing the employment of uninhabited vehicles for a variety of applications, the concept of a substantial fleet of such vehicles, operated from a mothership, able to host and support their operations during a mission scenario, is still a novel design challenge. In the initial design stages, when little of design effort has been committed, ship design details will be far from fully defined and are still amenable to change without significant implications on the programme budget, or schedule. Consequently, there is a need to consider how more informed, early, but yet significant design decisions can be made regarding the design of a mothership deploying a fleet of uninhabited vehicles. Delivering a mothership’s operational capability through a complement of uninhabited vehicles would determine the ship’s configuration. The proposed approach, developed as part of this research, consists of decision-making and ship concept design tools, and provides a holistic means of integrating aspects of a fleet of uninhabited vehicles into early stage mothership design. The first tool uses queueing theory and has been employed to capture the impact of the required facilities to host and support a fleet of uninhabited vehicles carried in the ship’s mission bay and subsequently impact on the overall ship design, as well as providing a measure of the ship’s mission effectiveness. The second tool utilises the advantages of architecturally-oriented initial ship design approach to obtain balanced mothership designs and perform some early stage naval architecture analyses. The overall aim of proposing a quantitative approach to mothership performance has been demonstrated, showing the impact of operating a fleet of uninhabited vehicles, resulting in large costly vessels. Several limitations identified during the development and the implementation of the new approach have suggested areas for future work. It was concluded that the proposed approach would be appropriate to inform early investigation of the implications of operating a fleet of uninhabited vehicles from a new mothership configuration, since it allows a relatively fast exploration and comparison of different mothership design options against cost-capability criteria. However, it is suggested that while favourable design options could emerge through such comparative studies, these would merit from further investigations using simulation techniques that could refine the inputs to such novel ship concepts