The Renault Formula1 racing team (Enstone, U.K.) builds its car chasses, wings and other components from composites. Tight manufacturing control and fast turnaround are crucial to meet race schedules. The team recently chose VISTAGY Inc.'s (Waltham, Mass.) trademarked FiberSIM software to help streamline its design and manufacturing processes.
For a recent race car, Renault engineers designed its cored sandwich-construction chassis in Dassault Systemes' (Paris, France) CATIA software (a CAD/CAE/CAM program originally developed for aerospace design), but then exported the design into FiberSIM, where they were able to create a detailed "library" of ply specifications, including material, layup sequence and fiber direction for each ply, linked to the geometry of each ply in the CAD model. According to Renault F1 team engineer Alan Duerden, epoxy prepregs, variously reinforced with woven or unidirectional glass, aramid or carbon fiber, were specified for the skins, over a core of aluminum and aramid honeycombs. FiberSIM enabled the team to simulate how the reinforcements would distort during layup; spot potential manufacturing issues created by ply deviation as a result of the complex contours in the chassis' composite mold; and determine optimum patterns and ply start /stop points. Once the outer skin schedule — more than 200 discrete pieces — was complete, a "mirror function" enabled inversion of the ply order to quickly generate the inner skin architecture, reports Duerden.
The software also saved much time and labor in the generation of flat patterns. Previously, technicians had cut patterns by hand, adding darts or splices where needed, then input the shapes to a CAD program to generate code for a computerized cutting machine. With FiberSIM, patterns were generated directly from the simulated ply data. According to Duerden, the patterns were projected onto clear template film with the help of a laser projection system, and then sent to the cutting machine. "Forty templates, for 152 plies, or 78 percent of the outer skin, were generated by FiberSIM," he reports. "Given the complexity of the chassis, that was an impressive figure." Renault documented labor savings of 30 percent for pattern templates, 20 percent in layup time for the outer skin and 25 percent for the inner skin, says Duerden. "Once we used FiberSIM to drive the laser projection system for layup, our production rate increased by 62 percent."