It also appeared quickly that this approach led to define several “design products” representing the aircraft; these design products being actually large information objects. One can also consider each of these design products as one perspective or point of view relevant to certain needs. And since the objective of design engineering is mainly to produce data for manufacturing, this package of design information is called Digital Mock-Up (DMU).
The DMU is consequently defined as an organized set of information, reflecting the different needs of the design teams, and structured according to a Product Structure. The Product Structure is mainly the core structure describing and managing how the drawing sets (when considering the output for manufacturing) are organized. It is also one of the key enablers of Configuration Management. From a technology perspective, the DMU relies on techniques similar to Virtual Reality. Thus it is possible to “navigate” in the DMU, to explore selected design areas.
The DMU is composed of several design products: each of these products is used to satisfy the engineering expectations of the different teams along the product lifecycle. For
instance:
• The Master Geometry resulting mainly from the definition of the aerodynamic shape of the aircraft can be used by the structure design team to derive a preliminary definition of the structure and associated design principles, by the manufacturing engineering teams to have a preliminary definition of the final assembly line operations and building, and by the operations engineering teams to study the servicing capability at the airport.
• The Space Allocation Model enables the systems engineering teams to perform the pre-installation of systems and various pieces of equipment. It also enables the design supportability teams to assess how the maintenance operations can be performed.
• Eventually, the Definition Model is the final stage of the DMU, from which the data for manufacturing is derived.
Some of the other DMU products are: the Design Principles, the Frontier Models, the
Stress Design Reference Base, the Systems/Equipment Installation Requirements
Dossier
The concepts of Master Geometry and Space Allocation Model also apply to tooling.
The DMU is now the central tool between the different engineering teams, and also a
fundamental dialog tool between Engineering and Manufacturing.
‘Fig.3. Development process’
2.4 Way of working, new jobs
2.4.1 Working around the DMU
As a consequence, concurrent engineering has placed the DMU at the heart of the technical quality of the design process. It has been necessary to establish around the DMU the appropriate technical control processes. This is mainly achieved through the DMU reviews. Held at regular time periods, the DMU reviews allow progressive validation of the product design thanks to the participation of the multidisciplinary teams.