Trans RINA, Vol 153, Part A1, Intl J Maritime Eng, Jan-Mar 2011
at UCL by the author and encapsulated in recent years by the Design Building Block (DBB) approach [20, 22]. The most extensive presentation of this approach was in Reference 17, which outlined in some detail each of the four main stages of the combined architectural and numerical synthesis process, where each stage produces an increasing level of definition of a new preliminary ship design. At each stage an appropriately holistic and numerically balanced definition of the ship design is produced,
performance aspects as is sensible at that stage in the design evolution.
using assessments of as wide a range of Table 2 summarises this process,
giving typical design decisions taken at each stage and, for the example in Reference 17, the granularity of the design study for each stage (i.e. the number of DBBs). The detail provided for each evolutionary step is spelt out for the example trimaran Littoral investigation in that reference.
Combat Ship
Table 2: Design Building Block design stages showing major design decisions and DBB granularity for the example in Reference 17
Design Preparation Selection of Design Style
Topside and Major Feature Design Phase (18 to 47) Design Space Creation
Weapons and Sensor Placement
Engine and Machinery Compartment Placement Aircraft Systems Sizing and Placement Superstructure Sizing and Placement
Super Building Block Based Design Phase (47 to 110) Composition of Functional Super Building Blocks Selection of Design Algorithms
Assessment of Margin Requirements Placement of Super Building Blocks Design Balance & Audit
Initial Performance Analysis for Master B.B.
Building Block Based Design Phase (110 to 343) Decomposition of Super Building Blocks by function Selection of Design Algorithms
Assessment of Margins and Access Policy Placement of Building Blocks Design Balance & Audit
Further Performance Analysis for Master B.B. General Arrangement Phase Drawing Preparation
The examples of concept design that are outlined in the following section were all produced by the UCL DRC using the DBB approach, rather than the limited
A-30
numerical synthesis approach of Figure 4. While the latter has the advantage of speed of
execution in
achieving an iterative balance, it can only do so by assuming specific (but not necessarily appropriate) hull form parameters, as the right hand side of the figure shows. It then needs to be followed by a parametric survey, which itself is of questionable veracity (see argument presented in Reference 23). Whereas the DBB approach is a more fully integrated synthesis of weight, space, form and the architectural dimension, which further opens up the concept solution space, as can be seen from the examples in the next section.
4. EXAMPLES OF CONCEPT STUDIES The
ship concept studies presented in this section
demonstrate the range of investigations that might be attempted under the broad category of initial, preliminary or concept studies, not with regard to types of ship roles (such as amphibiosity, logistics, air defence, land attack, escort
or motivations. general forms), but This purpose), ship rather is done
different in order
types (such as
combatants, aircraft carriers, LPD/H/A, submarines) or ship configurations (such as monohulls, multihulls, fast hull
concept to draw some
conclusions on the nature of concept studies and clarify the nature of Requirement Elucidation. The studies were largely motivated by specific and real world requirement investigations, covering a wide range of roles, types and configurations. They all
which utilises the ability of Corporation Limited’s tool
employ the DBB approach the Graphics Research PARAMARINE-
SURFCON’s to realise the DBB approach [24]. 4.1
LITTORAL COMBATANT SHIP
This study for the US Navy was the example drawn on to illustrate the process steps in the DBB approach in Table 2. While this example of a naval ship concept study was an extensive study, it could be said to be somewhat untypical of an early concept study, in that the requirement was spelt out in some detail by the US Navy (see details in Reference 17). Rather the study was more of an investigation as to whether the PARAMARINE- SURFCON tool could be used to produce “believable” designs and, in particular, could do so for unconventional solutions, such as the trimaran example produced by the UCL DRC. The requirements of the US Navy’s Littoral Combatant Ship were accessed from open information [25] and the fast (40 knot) trimaran configuration option was adopted. The use of the DBB approach revealed the advantage of a trimaran configuration, with its large box structure, able to accommodate defined watercraft assets that would otherwise have to be accommodated less effectively in
a with the narrower single watercraft hull. The other
arrangement feature shown in Figure 5 is that the aft part of the main hull is dominated by the four shafts for the waterjets, which have to be accommodated at the stern along
combination of the propulsive powers required and the deployment ramp. The study
©2011: The Royal Institution of Naval Architects
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