Theodore and Associates is unveiling the Uni-Chassis, a frameless body-on-chassis design that is lighter in weight, lower investment and lower cost compared to traditional body-on-frame and unibody designs, at the 2011 SAE World Congress in Detroit this week.
Uni-Chassis is a simple design made up of three basic elements: a front structure that utilizes a stressed engine to take suspension loads; a rear structure that utilizes the transaxle as a structural component; and, most importantly, the connection of front and rear structures by a structural tubular backbone that doubles as the torque tube.
Theodore sees three target markets that could benefit from the Uni-Chassis design—low volume speciality cars, coachbuilding, and plug-in hybrid and electric vehicles—with the latter having the largest commercial application.
Adding to the Uni-Chassis’ advantages of simplicity, efficiently and lower cost, are its flexibility and modularity. To increase wheelbase from one vehicle model to the next, the tubular backbone can be lengthened by as much as 20%, covering two and perhaps three classes of vehicles. The design is modular since front and rear structures can easily be substituted, enabling a true mix-and-match architecture.
The Uni-Chassis design also offers world-class torsional and bending stiffness.
Using Finite Element Analysis, we optimized the backbone design to achieve more than 13,000 ft. lbs./degree torsional stiffness and 47,000 lb./inch bending stiffness. That’s better than most supercars.
—Chris P. Theodore , President
The Uni-Chassis is made up of four aluminum suspension corner castings and aluminum extrusions, helping keep the weight and manufacturing expenses low. The aluminum tubular backbone also can be made from carbon fiber to further increase stiffness and reduce weight.
Theodore expects to have a complete, running Uni-Chassis vehicle, built around Ford GT parts and housed in a modified Shelby Cobra 427 body, for evaluation this fall.