This paper presents and demonstrates a new design thinking framework for early stage complex ship design, called the Design Knowledge Management Square (DKMS) framework. The DKMS framework provides a structure that explicitly incorporates the collaborative nature of complex ship design, contrary to other models or frameworks that primarily focus on the technical integration of tools and methods to describe early stage complex ship design. The DKMS framework is applied to three case studies: 1) multi-disciplinary early stage design of complex ships, 2) the integration of concept design generation and analysis methods, and 3) the application of design rationale to support collaborative design decision-making. The case studies show that the DKMS framework provides added value by explicitly describing both the collaborative and technical nature of complex ship design. Thereby the framework helps to analyse, support, and understand complex ship design.@en

Naval ships are designed to operate in hostile environments. As such, vulnerability reduction is an important aspect that needs to be assessed during the design. With the increased interest in electrification and automation on board naval ships, the vulnerability of distributed systems has become a major topic of interest. However, assessing this is not trivial, especially in early stage design, where the level of detail is limited, but consequences of design decisions are large. As such, a new method for assessing the vulnerability of distributed systems in early stage design has been developed. This method not only evaluates the vulnerability of a pre-defined ship concept, but also provides direction for finding other, potentially better concept. This is done from the perspective of operational capabilities. The method helps ship designers and naval staff in setting vulnerability requirements, developing new concepts, and identifying trade-offs in operational capabilities. The method uses a discrete Markov chain and the eigenvalues of the associated transition matrix. A test case considering vulnerability of a notional Ocean-going Patrol Vessel (OPV) with two different powering concepts illustrates the method. Furthermore, the new method is discussed in terms of design knowledge, including a comparison with other early stage vulnerability reduction methods. In addition to that, an improvement of an existing early stage design procedure for distributed ship systems is made, which shows how the various methods, including the new method, are envisioned to be applied in practice.@en

Vulnerability reduction is an important topic during the design of naval ships because they are designed to operate in hostile environments and because their on-board distributed systems are becoming increasingly complex. The vulnerability needs to be addressed in the early design stages already, in order to prevent expensive or time-consuming modifications in later, more detailed design stages. However, most existing methods for assessing the vulnerability are better suited for more detailed design stages. Furthermore, existing methods often rely on pre-defined damage scenarios, while damage–or system failure in general–may also occur in ways that were not expected beforehand. This paper proposes a method that addresses these gaps. This is done by incorporating several additions to an existing vulnerability method that has been developed by the authors, using a Markov chain. With this method, there is no longer a need for modelling individual hits or failure scenarios. The additions are illustrated by two test cases. In the first one, a notional Ocean-going Patrol Vessel is considered, and damage is related to physical locations in the ship. The second test case considers a chilled water distribution system in more detail, with failures modelled independent from the physical architecture. The quantitative nature of the results provide an indication of the generic, overall vulnerability of the distributed systems, which is meant to be used in the early design stages for identifying trade-offs and prioritising capabilities.

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Naval ships are designed to operate and survive in hostile environments. As such, vulnerability reduction is a major topic of interest during the design of a naval ship. For modern naval ships the vulnerability is largely determined by the design and layout of distributed systems. The vulnerability of these systems needs to be assessed early on, as design decisions made in this stage are decisive for the vulnerability of the final ship. Various early stage methods for assessing vulnerability exist, but a clear structure on when to use what types of methods, how these methods relate to each other, and how these methods provide relevant answers, is still lacking. To address this gap, this paper introduces a framework for early stage design of distributed systems, in the context of vulnerability reduction. This framework supports in choosing the right vulnerability method at the right design stage. The framework considers an operationally oriented systems perspective on vulnerability, and a physically oriented ship perspective. In addition to that, early stage design is subdivided in concept exploration and concept definition, which have different purposes and contributions in the design process. The framework provides examples of methods that can be used to investigate vulnerability for the various perspectives and design stages. These examples consider methods that have been developed by joint Delft University of Technology (TU Delft) and the Netherlands Defence Materiel Organisation (DMO) research efforts, as well as other methods. Opportunities and challenges for integrating these methods between themselves and in the design process in general are discussed.@en

Naval ships are designed to operate in a hostile environment. As such, vulnerability is an important aspect that needs to be assessed during the design. With the increased interest in electrification and automation on board naval ships, the vulnerability of distributed systems has become a major topic of interest. However, assessing this is not trivial, especially during the concept phase, where the level of detail is limited, but consequences of design decisions are large. Many existing vulnerability methods assess the vulnerability of pre-defined concepts, and focus on systems rather than capabilities. To address this, a new method for assessing the vulnerability of distributed systems in the concept phase has been developed. This method not only evaluates the vulnerability of a pre-defined concept, but also provides direction for finding other, potentially better solutions. This is done from a capabilities perspective. The method helps ship designers and naval staff in setting vulnerability requirements, developing new concepts, and identifying trade-offs in capabilities. The method uses a discrete Markov chain and the eigenvalues of the associated transition matrix. A test case considering vulnerability of a notional Ocean-going Patrol Vessel (OPV) with two different powering concepts illustrates the method.

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Naval ships are designed to operate in hostile environments, which exposes them to an ever-present risk of getting hit by weapons fired by an enemy. Potential consequences of a hit may be serious or even catastrophic. Therefore, survivability is a major design driver of naval ships. What is survivability, how do we measure it, and – most important – how do we design survivable naval ships?@en

In order to investigate to which extent naval ships can execute their operational scenario after damage, an early stage assessment of the vulnerability of distributed systems needs to be carried out. Such assessments are currently mostly done by evaluating the performance of predefined concepts. However, such an approach does not necessarily lead to the most desirable solution, since solutions outside the scope of the designer’s preconceived ideas or experience are inherently hard to investigate. This paper therefore proposes several steps towards an approach that enables a vulnerability assessment that is independent of predefined concepts. This is done by incorporating several additions to an existing system vulnerability approach developed by the authors, using a Markov chain. With this approach there is no longer a need for modelling individual hits or damage scenarios. Whereas the approach has previously been shown in concept, this paper introduces three improvements that contribute to the applicability of the approach: 1)it is scaled up in order to model a larger number of compartments and distributed systems, 2) the hit probabilities for different compartments can be adjusted, and 3) it is shown how the availability of main ship functions can be derived from the availability of individual connections. A test case that compares two powering concepts (conventional and full electric powering) of a notional Oceangoing Patrol Vessel (OPV) is provided to illustrate the principles behind the improvements. From the results the two main contributions of this paper can be obtained: 1)the possibility to assess the system vulnerability for different levels of required residual capacity at different impact levels, and 2) and the quantitative nature of the results, aiding ship designers and naval staff with understanding the consequences of various concepts on the system vulnerability. @en

This paper introduces a framework for analyzing distributed ship systems. The increase in interconnected and interdependent systems aboard modern naval vessels has significantly increased their complexity, making them more vulnerable to cascading failures and emergent behavior that arise only once the system is complete and in operation. There is a need for a systematic approach to describe and analyze distributed systems at the conceptual stage for naval vessels. Understanding the relationships between various aspects of these distributed systems is crucial for uninterrupted naval operations and vessel survivability. The framework introduced in this paper decomposes information about an individual system into three views: the physical, logical, and operational architectural representations. These representations describe the spatial and functional relationships of the system, together with their temporal behavior characteristics. This paper defines how these primary architectural representations are used to describe a system, the interrelations between the architectural blocks, and how those blocks fit together. A list of defined terms is presented, and a preliminary set of requirements for specific design tools to model these architectures is discussed. A practical application is introduced to illustrate how the framework can be used to describe the delivery of power to a high energy weapon.

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An early stage assessment of the vulnerability of systems on board naval ships needs to be carried out in order to ensure that naval ships can execute their operational scenario after hits or other damage. However, the broad scope of operational scenarios and impact levels, the interdependencies between systems and their environment, and the dynamic nature of vulnerability complicate the execution of such an analysis. While current methods mainly assess whether systems are still available after hits, the eventual question is whether the operational scenario can still be executed. An approach with a Markov chain is proposed to handle these complexities in early stage design. This paper specifically focusses on the effect of interactions between systems on vulnerability. It is shown that the fact that multiple systems are placed together in a layout already influences the vulnerability of the ship, regardless if they are related from a physical or logical point of view or not. Furthermore, the need for an integrated approach instead of assessing each system individually is demonstrated and quantified. The results of this methodology can be used by designers to make substantiated design choices with regard to prioritization of the different ship functions after hits. © 2018 Taylor & Francis Group, London.@en