After pioneering digital design in the aerospace industry 25 years ago, Dassault Aviation has implemented what it calls “the digital factory.” The Falcon 7X was the first aircraft to be produced using this concept, and the result was some impressive gains in manufacturing efficiency. Now Dassault has taken digitization one step further, by simulating the processes of aircraft completion and maintenance.
At the company’s virtual reality center in Saint-Cloud, near Paris, 3-D glasses effectively “transport” the design team into the digital mockup displayed on the large screen. The system allows them to take a collective look inside an interior fuselage bay where hydraulic, electrical and other systems are routed. With an astonishing degree of fidelity and accuracy, the mockup shows every connector, every fastener, every rivet. When the operator zooms in on a particular area of the bay the team discovers a problem: electrical wires are passing straight through a bracket that holds a hydraulic pipe in position. This digital “clash” has resulted from competing claims for space in the bay, exacerbated by the hydraulic and electrical system design teams. The problem can be resolved with a quick digital redesign. Previously, it might not have been discovered until the prototype aircraft was being equipped during final assembly.
The team members leave the theater and return to their individual workstations to correct the error. The hydraulic team will change the bend of the piping so the bracket can be repositioned. In so doing, they will be guided by the design software, which is intelligent enough to advise the maximum curvature that can be allowed. Even when sitting at their own desks, the designers can gain insight into the work of their colleagues on other sections or systems, since they share access to the single database.
“The digital mockup is a living tool,” explained Jerome Camps, engineering program manager for the Falcon 7X. “It allows us to implement the spirit of concurrent engineering. Starting with the loft lines and the preliminary layout of frames, the aircraft gradually solidifies as the various teams add their requirements,” he told AIN. “The result is an exact mathematical definition of the airplane, to accuracies as great as one thousandth of a millimeter,” he added.
But, he cautioned, to rely on a single database requires that it be well organized, in a family-tree style. This is especially so, considering that the same digital model is used to explore aerodynamics, structural loads, electromagnetic interference, air-conditioning effectiveness and so on.
Dassault Aviation is using version five of the Catia software it originally developed in the early 1980s. The Dassault group subsequently created a separate company, Dassault Systèmes, to market the software to other aerospace companies. Today, Dassault Systèmes sells a wide range of industrial 3-D software to many industries. The software package used to design the Falcon 7X is “95 percent Catia, plus a few tricks of our own,” said Camps.
Rethinking the Production Process
Once the final digital model of the Falcon 7X was agreed, it was released to Dassault’s engineering design section, so that production could be organized. This was an entirely paperless exercise, and no wood was cut to make physical mock-ups.
Camps noted that this new digital methodology required Dassault Aviation to completely reorganize its production processes. “An industrial and cultural shift was needed,” he said. For example, he explained, some personnel from the manufacturing side of the company were given access to the model well before the design freeze. Their input proved valuable, “although this was a strange experience for us designers,” he noted.
The same was true of the company’s key subcontractors. Thirty of them were brought together at Saint-Cloud, educated in the virtual ways of working, and then allowed to take the digital model to their factories, where they could do detailed design of the parts that they would supply for the Falcon 7X. “By means of this virtual platform, we had full day-by-day visibility, together with our partners,” said Camps.
The production organization allowed suppliers to use the database in various novel ways. The suppliers of jigs and tools that hold and form complicated parts, such as curved pipes and non-return valves, used the data to simplify their own design task. Within Dassault itself, the database was used to program the robots that drill the sub-assemblies. In fact, digital modeling has led to robotic assembly of fuselage panels at the Argenteuil factory. Dassault believes this to be a world first.
Workers on the shop floor at Dassault’s production sites had direct access to the entire database with Windows-equipped notebooks. With only two clicks, they could check the characteristics and dimensions of every part. They, too, could rotate the digital model to gain insight into hidden areas of structure, using touch-screen controls. It wasn’t long before a strong feedback loop developed between production and design.
According to Camps, the result has been that “series production quality was achieved with the first Falcon 7Xs.” Even the first aircraft to be produced will be sold to a commercial customer, once its role in the test program is finished. “We don’t build prototypes any more,” he said.
Digital modeling has recently been extended to the work done in the company’s completion centers at Bordeaux and Little Rock. Cabin furniture is now being designed using the Catia system. Meanwhile, the virtual platform is now helping to design the Neuron, an unmanned combat air vehicle demonstrator that is being produced by a pan-European aerospace consortium led by Dassault Aviation.
Maintenance Goes Digital
Dassault has created “virtual” human mechanics, pilots and production workers, who are used with the digital model to perform a dry run of mechanical tasks, for the purpose of suggesting possible improvements in aircraft design and processes.
To design the cockpit for the comfort of pilots, Dassault engineers measured the company’s test pilots, supplying the data to the virtual model. Designers used the data to explore some key certification criteria for the Falcon 7X, such as the ease of reaching and operating the sidestick and the views through the cockpit windows.
The company also conducted maintenance feasibility studies to answer such questions as how involved it would be for a typical maintenance engineer to change the air turbine starter. Was the access door correctly positioned, so that he could reach into the bay while standing on a ladder? How much of the bay’s interior could he see from that position? Were his arms long enough to perform the task comfortably?
In another example, the program modeled the inspection of the center fuselage tank. Designers noticed that although the mechanic could enter satisfactorily through the access door, a fuel line impeded further progress. “We changed the routing of that pipe the same day,” recalled Jerome Camps, engineering program manager for the Falcon 7X.
Needless to say, the digital model was also used to produce maintenance documentation that is now being used to service and overhaul the Falcon 7X. “So far, it seems that the maintenance tasks that we predicted digitally are proving to be practical,” Camps reported. –C.P.