Completed Research

Compliant Link Suspensions

Principal investigators:

John Ziegert, Bashah Ayalew and Harry Law

Department of Mechanical Engineering:

Automotive engineering
(864) 283-7222
ziegert@clemson.edu

Graduate students:

Vincent Lee and Souharda Raghavendra

Sponsor:

BMW

Brief abstract:

Current automotive suspension systems are composed of discrete elements intended to achieve the following functions:

• Kinematics — a linkage system to guide the motion of the wheel/axle relative to the body. (If necessary a target vehicle or system to be replaced will be picked.)
• Compliance — a spring/bushing system to restore the suspension to its nominal position following disturbances and reduce transfer of road irregularities to the chassis,
• Damping — an energy absorbing system to reduce the persistence of vibrations.

The objectives of this project are to:

• Develop lightweight suspension concepts where the kinematics, elastic and damping functions are fulfilled — at least partially — by compliant links.
• Main target is mass reduction; additional benefits in reduced complexity and cost as well as reduced demand for package space.
• Demonstrate concepts with schematic prototypes.

Impact:

Consumers benefit by having suspensions that are lighter in weight and less complex, thereby saving initial cost and decreasing fuel consumption.

Publication:

Vincent Lee, Souharda Raghavendra, Beshah Ayalew, John Ziegert, “Compliant Link Suspension,” submitted to 2009 SAE Congress.

Preliminary results:

Following design studies, a conceptual design was selected for detailed study. It replaces a lateral control arm and the coil spring with a ternary-supported compliant link that both stores energy during wheel motion and provides kinematic guidance to the wheel. Simulations were used to evaluate and optimized design dimensions. A prototype suspension was constructed, and its stiffness and elasto-kinematic properties were evaluated and compared to the reference suspension with rigid links. Results show that it is possible to achieve nearly equivalent elasto-kinematic performance with the compliant link suspension, while achieving lower mass and saving space.

CAD design of prototype suspension fixture

Simulation of prototype suspension concept