Design and Analysis of the Ford GT Spaceframe 2004-01-1255

The Ford GT is a high performance sports car designed to compete with the best that the global automotive industry has to offer. A critical enabler for the performance that a vehicle in this class must achieve is the stiffness and response of the frame structure to the numerous load inputs from the suspension, powertrain and occupants.

The process of designing the Ford GT spaceframe started with a number of constraints and performance targets derived through vehicle dynamics CAE modeling, crash performance requirements, competitive benchmarking and the requirement to maintain the unique styling of the GT40 concept car.

To achieve these goals, an aluminum spaceframe was designed incorporating 35 different extrusion cross-sections, 5 complex castings, 4 smaller node castings and numerous aluminum stampings. A highly iterative design process which utilized continuous CAE analysis of the stiffness, crash and NVH performance and cross sectional properties of the various extrusions was used to balance the frame performance with manufacturing, cost and weight requirements. The resulting spaceframe design features a large central tunnel to house the centrally mounted fuel tank, highly optimized yet non-intrusive rocker sections, a series of stiffener bars removable for engine installation and service and an upper structure designed to transfer crash, bending and torsional loads around door openings which extend well into the roof area. The front and rear bumper structures including longitudinally mounted crush rails are bolted to the frame for ease of repair and a bolted-in magnesium cross member provides retention for the fuel tank. The remainder of the primary frame structure is mig welded while the numerous stamped panels are riveted and bonded to allow the thinnest possible material to be used.