A COMPREHENSIVE APPROACH TO SURVIVABILITY ASSESSMENT IN NAVAL SHIP CONCEPT DESIGN

2021 ◽  
Vol 156 (A4) ◽  
Author(s):  
A S Piperakis ◽  
D J Andrews
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Ship Design ◽  
Assessment Tools ◽  
Concept Design ◽  
Trade Offs ◽  
Assessment Approach ◽  
The Uk ◽  
Constituent Elements ◽  
The Impact

Alongside deploying weapons and sensors what makes a warship distinct is its 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 cost cutting, often aimed at aspects, such as survivability, which may be difficult to quantify in a manner that facilitates cost capability trade-offs. Therefore, to meet ever-reducing budgets, in real terms, innovation in both the design process and the design of individual ships is necessary, especially at the crucial early design stages. Computer technology can be utilised to exploit architecturally orientated preliminary design approaches, which have been conceived to explore innovation early in the ship design process and the impact of such issues as survivability. A number of survivability assessment tools currently exist; however, most fail to integrate all the constituent elements of survivability (i.e. susceptibility, vulnerability and recoverability), in that they are unable to balance between the component aspects of survivability. Some of these tools are qualitative and therefore less than ideal in specifying survivability requirements, others are aimed towards the more detailed design stages where implementing changes is heavily constrained or even impractical. This paper presents a survivability assessment approach combining various tools used by UCL and the UK Ministry of Defence, as well as a new approach for recoverability assessment. The proposed method attempts to better integrate and quantify survivability in early stage ship design, which is facilitated by the UCL derived, architecturally focused, design building block approach. The integrated survivability method is demonstrated for a set of naval combatant concept designs and for two replenishment ship studies to test the robustness of the proposed approach.

The Sophistication of Early Stage Design for Complex Vessels

2018 ◽  
Vol Vol 160 (SE 18) ◽  
Author(s):  
D Andrews
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Ship Design ◽  
Concept Design ◽  
Design Synthesis ◽  
Simplified Approach ◽  
Overall Design ◽  
Intact Stability ◽  
Early Stage Design ◽  
Metacentric Height

Prior to the introduction of computers into Early Stage Ship Design of complex vessels, such as naval ships, the approach to synthesising a new design had been via weight equations. When it was realised that modern naval vessels (and some sophisticated service vessels) were essentially space driven initial (numerical) sizing needed to balance weight and space, together with simple checks on resistance & powering, plus sufficient intact stability (i.e. simple metacentric height assurance). All this was quickly computerised and subsequently put on a spread-sheet to iteratively achieve weight and space balance, while meeting those simple stability and R&P checks. Thus suddenly it became possible to produce very many variants, for both trade-off of certain requirements (against initial acquisition cost) as well (apparently) optimal solutions. However as this paper argues this speeding up of a very crude synthesis approach, before rapidly proceeding into feasibility investigations of the “selected design”, has not led to a quicker overall design process, nor have new ship designs been brought earlier into service, in timeframes remotely comparable to most merchant ships. It is the argument of this paper that such a speeding up of an essentially simplified approach to design synthesis is not sensible. Firstly, there is the need to conduct a more sophisticated approach in order to proceed in a less risky manner into the main design process for such complex vessels. Secondly, further advances in computer techniques, particularly those that CAD has adopted from computer graphics advances, now enable ship concept designers to synthesise more comprehensively and thereby address from the start many more of the likely design drivers. The paper addresses the argument for a more sophisticated approach to ESSD by first expanding on the above outline, before considering important design related issues that are considered to have arisen from major R.N. warship programmes over the last half century. This has been done by highlighting those UK naval vessel designs with which the author has had a notable involvement. The next section re-iterates an assertion that the concept phase (for complex vessels) is unlike the rest of ship design with a distinctly different primary purpose. This enables the structure of a properly organised concept phase to be outlined. Following this the issue of the extent of novelty in the design of a new design option is spelt out in more detail for the seven categories already identified. The next section consists of outlining the architecturally driven approach to ship synthesis with two sets of design examples, produced by the author’s team at UCL. All this then enables a generalised concept design process for complex vessels to be outlined, before more unconventional vessels than the naval combatant are briefly considered. The concluding main section addresses how a range of new techniques might further alter the way in which ESSD is addressed, in order to provide an even better output from concept to accomplish the downstream design and build process. The paper ends with a summary of the main conclusions.

scholarly journals CHOOSING THE STYLE OF A NEW DESIGN - THE KEY SHIP DESIGN DECISION

2021 ◽  
Vol 160 (A1) ◽  
Author(s):  
D Andrews
Keyword(s):  
Design Process ◽  
Building Block ◽  
Early Stage ◽  
Ship Design ◽  
Design Decision ◽  
Design Issues ◽  
Design Study ◽  
Design Option ◽  
The Impact ◽  
Block Approach

As a former senior designer of naval vessels and, more recently, a leading researcher in ship design, the author has previously presented a description of the ship design process in terms of the important decisions a ship designer makes in concept exploration. Such decision are made consciously or unconsciously in order to produce a new design or, preferably, any design option. It has been contended in many publications that the first real decision that a ship designer makes, in order to proceed, is the selection of the “style” of the design study or of a specific design option. This term was adopted in order to cover, not just a host of design issues and standards implicit in a given study, but also, at this very initial step, the overall characteristics of any particular study. So the term style could be said to be doubly important. The current paper considers the nature of the early ship design process for complex multi-functional vessels and then retraces the origins of the particular use of the term, where it was seen as the last of the five elements in Brown and Andrews’ 1980 encapsulation of the ship design issues that matter to the naval architect, incorporated in the term “S to the 5th”. This leads on to consideration of the various aspects of design style, many of which could be considered “transversals” as they apply across the naval architectural sub-disciplines and to the component material sub-systems comprising a ship. One of the distinctive advantages of the architecturally driven ship synthesis or Design Building Block approach is that it can address many of these style issues in the earliest descriptions of an emergent design study. Examples, drawing on a range of built Royal Navy ship designs, are presented to show their top-level style characteristics, followed by a series of ship design research studies illustrating how the impact of specific component style aspects can be investigated in early stage ship design, using the UCL Design Building Block approach. Finally, recent research led investigations into integrating ship style into early stage ship design are summarized to demonstrate why the choice of “style” is seen to be The Key Ship Design Decision.

scholarly journals Choosing the Style of a New Design - The Key Ship Design Decision

2018 ◽  
Vol Vol 160 (A1) ◽  
Author(s):  
D Andrews
Keyword(s):  
Design Process ◽  
Building Block ◽  
Early Stage ◽  
Ship Design ◽  
Design Decision ◽  
Design Issues ◽  
Design Study ◽  
Design Option ◽  
The Impact ◽  
Block Approach

As a former senior designer of naval vessels and, more recently, a leading researcher in ship design, the author has previously presented a description of the ship design process in terms of the important decisions a ship designer makes in concept exploration. Such decision are made consciously or unconsciously in order to produce a new design or, preferably, any design option. It has been contended in many publications that the first real decision that a ship designer makes, in order to proceed, is the selection of the “style” of the design study or of a specific design option. This term was adopted in order to cover, not just a host of design issues and standards implicit in a given study, but also, at this very initial step, the overall characteristics of any particular study. So the term style could be said to be doubly important. The current paper considers the nature of the early ship design process for complex multi-functional vessels and then retraces the origins of the particular use of the term, where it was seen as the last of the five elements in Brown and Andrews’ 1980 encapsulation of the ship design issues that matter to the naval architect, incorporated in the term “S to the 5th”. This leads on to consideration of the various aspects of design style, many of which could be considered “transversals” as they apply across the naval architectural sub-disciplines and to the component material sub-systems comprising a ship. One of the distinctive advantages of the architecturally driven ship synthesis or Design Building Block approach is that it can address many of these style issues in the earliest descriptions of an emergent design study. Examples, drawing on a range of built Royal Navy ship designs, are presented to show their top-level style characteristics, followed by a series of ship design research studies illustrating how the impact of specific component style aspects can be investigated in early stage ship design, using the UCL Design Building Block approach. Finally, recent research led investigations into integrating ship style into early stage ship design are summarized to demonstrate why the choice of “style” is seen to be The Key Ship Design Decision.

Exploring System of Systems Resilience vs. Affordability Trade-Space Using a Bio-Inspired Metric

2021 ◽  
pp. 1-13
Author(s):  
Abheek Chatterjee ◽  
Richard Malak ◽  
Astrid Layton
Keyword(s):  
Design Process ◽  
Early Stage ◽  
System Of Systems ◽  
Ecological Research ◽  
Highly Efficient ◽  
Trade Offs ◽  
System Order ◽  
Range Of Values

Abstract The objective of this study is to investigate the value of an ecologically inspired architectural metric called the Degree of System Order in the System of Systems (SoS) architecting process. Two highly desirable SoS attributes are the ability to withstand and recover from disruptions (resilience) and affordability. In practice, more resilient SoS architectures are less affordable and it is essential to balance the trade-offs between the two attributes. Ecological research analyzing long-surviving ecosystems (nature's resilient SoS) using the Degree of System Order metric has found a unique balance of efficient and redundant interactions in their architecture. This balance implies that highly efficient ecosystems tend to be inflexible and vulnerable to perturbations while highly redundant ecosystems fail to utilize resources effectively for survival. Motivated by this unique architectural property of ecosystems, this study investigates the response to disruptions vs. affordability trade-space of a large number of feasible SoS architectures. Results indicate that the most favorable SoS architectures in this trade-space share a specific range of values of Degree of System Order. This suggests that Degree of System Order can be a key metric in engineered SoS development. Evaluating the Degree of System Order does not require detailed simulations and can, therefore, guide the early stage SoS design process towards more optimal SoS architectures.

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

2017 ◽  
Vol 33 (02) ◽  
pp. 81-100
Author(s):  
Rachel Pawling ◽  
Victoria Percival ◽  
David Andrews
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Ship Design ◽  
Complex Process ◽  
University College London ◽  
The University ◽  
Convenient Model ◽  
Balanced Solution ◽  
Block Approach ◽  
Design Spiral

For many years, the design spiral has been seen to be a convenient model of an acknowledged complex process. It has virtues particularly in recognizing the ship design 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 postgraduate design investigation using the University College London 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 that there are distinct regions of cliffs and plateau 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.

scholarly journals How fast should social restrictions be eased  in England as COVID-19 vaccinations are rolled out?

2021 ◽  
Author(s):  
David Miles ◽  
Adrian Heald ◽  
Mike Stedman
Keyword(s):  
Healthcare Services ◽  
Key Factors ◽  
Healthcare Provision ◽  
Factors Affecting ◽  
Education Outcomes ◽  
Trade Offs ◽  
Standards Of Living ◽  
Life Years ◽  
The Uk ◽  
The Impact

Vaccination against the COVID-19 virus began in December 2020 in the UK and is now running at 5% population/week. High Levels of social restrictions were implemented for the third time in January 2021 to control the second wave and resulting increases in hospitalisations and deaths. Easing those restrictions must balance multiple challenging priorities, weighing the risk of more deaths and hospitalisations against damage done to mental health, incomes and standards of living, education outcomes and provision of non-Covid-19 healthcare. Weekly and monthly officially published values in 2020/21 were used to estimate the impact of seasonality and social restrictions on the spread of COVID-19 by age group, on the economy and healthcare services. These factors were combined with the estimated impact of vaccinations and immunity from past infections into a model that retrospectively reflected the actual numbers of reported deaths closely both in 2020 and early 2021. It was applied prospectively to the next 6 months to evaluate the impact of different speeds of easing social restrictions. The results show vaccinations are significantly reducing the number of hospitalisations and deaths. The central estimate is that relative to a rapid easing, the avoided loss of 57,000 life years from a strategy of relatively slow easing over the next 4 months comes at a cost in terms of GDP reduction of around £0.4 million/life-year loss avoided. This is over 10 times higher than the usual limit the NHS uses for spending against Quality Adjusted Life Years (QALYs) saved. Alternative assumptions for key factors affecting give significantly different trade-offs between costs and benefits of different speeds of easing. Disruption of non-Covid-19 Healthcare provision also increases in times of higher levels of social restrictions. In most cases, the results favour a somewhat faster easing of restrictions in England than current policy implies.

A Novel Ship Subdivision Method and its Application in Constraint Management of Ship Layout Design

2011 ◽  
Vol 27 (03) ◽  
pp. 137-145 ◽  
Author(s):  
Deniz de Koningh ◽  
Herbert Koelman ◽  
Hans Hopman
Keyword(s):  
Design Process ◽  
Early Stage ◽  
A Priori ◽  
Layout Design ◽  
Management Program ◽  
Management Tool ◽  
Constraint Management ◽  
Damage Stability ◽  
Actual Design ◽  
The Impact

Conventionally, the rooms and spaces of a ship are either modeled as volumetric entities, or with the aid of bulkheads and decks. According to our knowledge, no simple representation exists where both entities can be modeled independently, and where automated conversion from one view (volumetric) to the other (planes) is possible. This paper introduces a simple yet effective approach, where a ship designer can mix the use of volumes and planes in any fashion. Furthermore, this modeling method is applied in a novel tool to manage ship subdivision constraints. As quite a few numerical constraints are known a priori, they can be defined in a list and assigned to specific subdivision elements. Examples are bulkhead locations or required tank volumes or deck areas. A constraint management tool is developed that evaluates the ship layout design during the design process. The designer will be able to modify or add constraints, and the tool will support the designer by managing these constraints during the design process. If the hull form changes, all submitted rules will be updated according to the new main particulars. If one of the constraints does not comply, an adjustment or alternative can be chosen at that moment and the impact of this change is directly visible. The designer can also ask the tool to provide a ship layout design that complies best with the constraints entered. When the Constraint Management program is used, a feasible ship compartment design can be made in a quick manner and the designer is kept from making errors. This means that a correct ship layout model is available on which probabilistic damage stability calculations and weight estimations can be performed in an early stage. This method has been implemented in a computer program, so actual design examples are discussed.

Ensuring Successful Ship Construction Outcomes: Using More Physics-Based Design Tools in Early Concept Design

2012 ◽  
Author(s):  
Robert G. Keane
Keyword(s):  
Collaborative Design ◽  
High Performance ◽  
Early Stage ◽  
Ship Design ◽  
Design Tools ◽  
Concept Design ◽  
Ship Construction ◽  
Design Engineers ◽  
Naval Ship ◽  
American Society

The Navy has experimented with many ways to improve the producibility of naval ship designs. In terms of effectiveness - does the ship do what it is supposed to do - the Navy has been reasonably successful. However, in terms of efficiency - are the ships efficient to produce and own - there is still much room for improvement. Design for producibility – being able to efficiently produce a warship - must start during the earliest stages of concept design and continue to be addressed during the subsequent pre-production processes. However, many early stage naval ship design engineers either do not recognize this need or do not know how to design for producibility. A number of improvements to early stage ship design capabilities are being developed in order to make the process both effective and efficient. This paper addresses the critical stage of the collaborative Design-Build-Own process of initially sizing the hull during concept design. The author proposes the development and use of more physics-based design tools during concept design, such as those being developed under the DoD High Performance Computing Modernization Program’s Computational Research & Engineering for Acquisition Tools & Environments (CREATE) – SHIPS Project. These new ship design methodologies will enable conceptual design engineers to adequately size a ship to meet military performance requirements and to have a low enough ship density to ensure successful ship construction outcomes. The director of a Netherlands’ shipyard which designs and builds surface combatants recently stated at a luncheon of the American Society of Naval Engineers (ASNE), “We learned a long time ago to give ourselves enough space to build a ship – steel is cheap, air is free!”

scholarly journals Managing information flow and design processes to reduce design risks in offsite construction projects

2019 ◽  
Vol 26 (2) ◽  
pp. 267-284 ◽  
Author(s):  
Monty Sutrisna ◽  
Jack Goulding
Keyword(s):  
Design Process ◽  
Information Flow ◽  
Construction Projects ◽  
Specific Model ◽  
Content Type ◽  
Environment Domain ◽  
Risk Framework ◽  
Value Propositions ◽  
The Uk ◽  
The Impact

PurposeFollowing the increasing need for faster construction, improved quality and evidence value propositions, offsite construction is increasingly being proffered as a viable contender to “traditional” construction approaches. However, whilst evidence supports the move towards offsite, its uptake has been lower than expected. Whilst the precise reasons for this seem to be influenced by a number of issues, including contextual drivers and market maturity; some project stakeholders also view offsite as carrying greater risks. The purpose of this paper is to report on the quality of information flow, in particular, the impact and influence of this on design risks in offsite construction projects.Design/methodology/approachAn existing design risk framework is used as the point of departure for this research. This is further expanded into a specific model for evaluating offsite construction projects design risks, the rubrics of which were informed by two case studies of offsite construction projects in Australia and the UK analysed with a process-tracing technique. Whilst these cases were geographically separated, the constructs were aligned to uncover fundamental design information requirements and concomitant risks associated with offsite.FindingsThe findings of the research reported in this paper include the crucial information feeding into the design process emanating from the lifecycle of offsite construction projects, namely, design, offsite (manufacturing), handling and transporting, site works and installation and also occupancy. These are contextualised within the four categories, namely, client requirements, project requirements, regulation aspects and social aspects and the final outcomes were summarised into a holistic diagram.Originality/valueGiven that the offsite construction has shifted the working paradigm into assigning a significant level of efforts and emphasis at the front end of the construction projects, the importance of its design process and hence design risks management has gone up significantly in construction projects delivered using this technique. This research and paper contributes significantly to the built environment domain by identifying the crucial aspects along the project lifecycle to be considered to minimise the potential occurrence of design risks and hence increasing the confidence of project stakeholders in adopting offsite construction techniques in their projects.

Exploring System of Systems Resilience vs. Affordability Trade-Space Using a Bio-Inspired Metric

2020 ◽  
Author(s):  
Abheek Chatterjee ◽  
Richard Malak ◽  
Astrid Layton
Keyword(s):  
Design Process ◽  
Early Stage ◽  
System Of Systems ◽  
Ecological Research ◽  
Highly Efficient ◽  
Trade Offs ◽  
System Order ◽  
Range Of Values

Abstract The objective of this study is to investigate the value of an ecologically inspired architectural metric called the Degree of System Order in the System of Systems (SoS) architecting process. Two highly desirable SoS attributes are the ability to withstand and recover from disruptions (resilience) and affordability. In practice, more resilient SoS architectures are less affordable and it is essential to balance the trade-offs between the two attributes. Ecological research analyzing long-surviving ecosystems (nature’s resilient SoS) using the Degree of System Order metric has found a unique balance of efficient and redundant interactions in their architecture. This balance implies that highly efficient ecosystems tend to be inflexible and vulnerable to perturbations while highly redundant ecosystems fail to utilize resources effectively for survival. Motivated by this unique architectural property of ecosystems, this study investigates the response to disruptions vs. affordability trade-space of a large number of feasible SoS architectures. Results indicate that the most favorable SoS architectures in this trade-space share a specific range of values of Degree of System Order. This suggests that Degree of System Order can be a key metric in engineered SoS development. Evaluating the Degree of System Order does not require detailed simulations and can, therefore, guide the early stage SoS design process towards more optimal SoS architectures.

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