Γαλλικά Ναυπηγεία DCNS

"120 θέσεις εργασίας TopSolid ήρθαν να αντικαταστήσουν το λογισμικό Euclid σε όλα τα τμήματα σχεδιασμού/παραγωγής των Γαλλικών ναυπηγείων DCNS."

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Name:	DCNS
Address:	Indret, 44620 La Montagne France
Tel:	+33 3 81 46 21 07
Fax:	+33 3 81 46 21 57
Web:	http://www.dcnsgroup.com
Activity:	Naval shipbuilder
Licences:	120 TopSolid'Cam, TopSolid'Pdm

When density goes hand-in-hand with CAD/CAM integration

Designing naval vessels involves working around issues unlike those in any other industrial business sector: extreme density of equipment, a variety of technologies, including nuclear technology, the absence of standards, etc. The design tool must therefore be totally CAD/CAM integrated, whilst also highly specific to this sector.

The company DCN added an ‘–S’ to its name when Thales acquired a 25% shareholding in its capital. The DCNS Group presently employs 13,000 people across its seven sites and has a turnover of €2.5 billion. As Europe’s leading naval shipbuilder, the company not only designs and builds vessels for the French Navy, but also for the Naval Forces of other countries. The first distinctive feature of armed vessels, whether they be aircraft carriers or nuclear submarines, is that there are no two alike. Furthermore, over the course of the development phase lasting several years, the project undergoes a significant number of changes. As a result, there are hardly any standards established for the industry. Even the nuts and bolts used for assembly are unique! As for the second distinctive feature: the diversity of elements found together in the same envelope is extremely wide-ranging. In fact, in terms of the density and complexity of the technologies used, no other type of construction can rival that of an SSBN (nuclear-powered ballistic missile submarine). If DCNS itself is the prime contractor and integrator for the complete set of submarine systems and equipment, a project with this level of sophistication still warrants the participation of almost 6,000 sub-contracting partners!

Assembling a giant mechanical construction

We were able to visit the Propulsion Center located in Indret near Nantes, France. The site is organized into an engineering division, responsible for developing the systems required between the initial energy source and the propeller, and a products division which develops and produces the strategic equipment: components for nuclear reactors (for the prime contractor Areva), heat exchangers, reducing gears, and mechanical transmission equipment (line shafting, propellers).

Each designing/producing unit ends up functioning like an equipment manufacturer to serve the engineering of the overall vessel. “Usually, the project evolves in accordance with milestones clearly identified in a V-cycle and regularly-held design reviews. This enables exchanges to take place between each division for the consolidation of technical data and performance validation. Ship engineering, at a higher level, is responsible for the global integration of all these systems and equipment within the structure of the vessel.” explains François Triconnet, CAD/CAM Project Manager. A giant mechanical construction therefore, and a particularly complex one at that…

In 2005, the Management at DCNS decided to renew its digital design tools. The investment process, invitation to tender, and benchmarking lasted a year; Missler Software was finally selected in preference to companies with bigger structures… 120 TopSolid CAD/CAM workstations have therefore come to replace Euclid software on all the manufacturer’s business lines. The floating licenses are shared between four sites via a general server. The investment budget has been equally divided over the licenses, the servers and workstations and the deployment. What is more, it was Missler Software itself that was responsible for the entire project, from responding to the invitation to bid, to training the operators and including the deployment of licenses over its customer’s IT environment - no mean feat, in view of the significance of the investment and the technical issues at stake.

Design AND manufacture!

TopSolid is used to model the mechanical equipment, from the mechanically-welded chassis, to sheet metal parts, including the assemblies and piping lines. TopSolid’Cam, on the other hand, is used to generate the machining programs. It was precisely this aspect of integration between manufacture and design that appealed so much to DCNS when taking their decision. The machining is indeed frequent, even sometimes involving parts of gigantic proportions and ranges from simple turning to continual 5-axis milling. Verification of the numerically-controlled programs is based on the specialized Spring Technologies tool: NCSimul. The designs for each item of equipment are divided amongst the different teams. To ensure coherence, it is possible to import the vessel environment. Thus, each draftsman develops the specific elements they are responsible for, all the time ensuring that the interfacing with their colleague’s adjacent equipment is perfect.

Ansys’s structural analysis tool DesignSpace, which is integrated into TopSolid, is used by draftsmen for resolving static load issues and pre-sizing the parts. To study complex loads, DCNS calls upon the expertise of its calculations service. In particular, this department uses solutions such as Ansys’s WorkBench. It should also be pointed out that this is integrated with the Parasolid modeler (also adopted by TopSolid) which facilitates the exchange of geometries between CAD and the calculation code. As François- Xavier Boulaire, Design Draftsman, explains: “Normally, the mechanical design engineer never works in isolation. We can count on the assistance of structural engineers to resolve structural or thermal problems. Different codes, such as those from Ansys Fluent, are used for sizing, validating and certifying developments.” Missler Software has also developed specific gateways for optimizing exchanges between the solutions used by the different departments in the company. For example, an interface allows each designer to export the global geometry of his work to ship engineering, which itself is based on Cadds 5 and WindChill for the management of all the data for the vessel.

There was a missing link in the numerical chain set up at the Propulsion Business Unit: management of numerical models. This was put right in June. By deploying the PDM tool offered by Missler Software and integrated into TopSolid, the draftsmen may now manage both their CAD files and the associated CNC programs. Note that at company level, data consolidation between all those involved on each project is performed via an Oracle database, linked to the CAPM.

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