Etienne Duchateau

The preliminary design of service vessels and warships in particular is a complex process. It involves the translation of stakeholder’s needs, which result from required missions, into basic functions and systems solutions. Only by following these steps it is possible to obtain the complex requirements posed on the design. In other words it is difficult, if not impossible, to elucidate all requirements for a service vessel without actually creating concept designs that show interaction between the form (concept design) and function (performance) of a service vessel. This process can be described by the classic systems engineering V-diagram, in which the relation between function and form are described.

The developments by van Oers 2011 and DeNucci 2012 both focus on the form (design) of ship configuration on the right side of the V-diagram. They both assume that initial decisions on wanted functions and systems and their requirements have already been taken. However these initial decision making steps are not trivial, they are very much dependant on the ability of the design team to translate functions into a coherent set of system solutions. Only after an initial set of systems solutions has been chosen, can the performance and effectiveness of these choices be verified through a concept design (possible with the tools of the mentioned authors).

The present research aims at closing the “loop” of the V-model, i.e. capturing the knowledge created when verifying form versus function, allowing the (re)use of this knowledge in subsequent preliminary design iterations. Captured knowledge during all decision steps can include:

Requirements knowledge
Requirements elucidation is a key step in the conceptual design stage. The functional analysis of the ships ``required'' mission capabilities sheds light on the final requirements. Only by making concept designs can the actual impact of requirements be made visible. Requirements are often conflicting in which case a trade-off must be made, impacts of such trade-off's increase the knowledge of the requirements and makes decision making easier.
Systems selection knowledge
Different system selections or combinations can alter the functionality and performance of the ship. This is based on the requirements that the ship is meant to fulfil (e.g. are the initial systems satisfactory for the mission/task). Are all the functions of the ship fulfilled? If not, do we need more, less, and/or different systems? Selection of the right system solutions is not straight forward and can have great influence on performance (i.e. the so called ``-ilities'').
Configuration knowledge
The configuration and arrangement of the systems in/on the vessel greatly influences the performance and functionality of the systems and the vessel as a whole (e.g. relative and global position of objects). This type of knowledge capturing has been partially covered by DeNucci 2012.
Ship/system performance knowledge
Performance of the generated designs and/or systems can give new insight into the possibilities of the ship and its currently selected systems (``-ilities''). Is the ships performance satisfactory? If not, why? Are the requirements too challenging?

Challenges lay in finding appropriate methods and tools to capture these types of knowledge and then (re)use the knowledge in subsequent design iterations or different ship designs. In addition input can be generated for use with the already available preliminary design tool of van Oers 2011.

References

  •     B.J. van Oers, A Packing Approach for the Early Stage Design of Service Vessels, PhD thesis, Delft University of Technology, 2011.
  •     T. DeNucci, Capturing Design: Improving Conceptual Ship Design Through the Capture of Design Rationale, PhD thesis, Delft University of Technology, 2012.