Shape Recovery Simulation of Flexible Airdam 2013-01-0166

Airdam is an aerodynamic component in automobile and is designed to reduce the drag and increase fuel efficiency. It is also an important styling component. The front airdam below the bumper is to direct the air flow away from the front tires and towards the underbody, where the drag coefficient becomes less.

The flexible airdam is made of Santoprene™ - thermoplastic vulcanizates (TPV), which belongs to thermoplastic elastomer (TPE) family. When a vehicle is parked over a parking block, the flexible airdam will be under strain subjected to bending load from the parking block. If the airdam is kept under constant strain for a certain period, a set will occur and the force will decay over a period of time. Due to the force decay, the stress will reduce and this behavior is called as stress relaxation. Once the airdam is removed from the block, it will be in its deformed position and try to recover its original shape which will affect the fuel efficiency and appearance of the vehicle, until it recovers the original shape. This paper explains the material behavior (hyperelastic and viscoelastic) of TPV and its representative material model in Abaqus. This is followed by a simple feasibility study done on a rectangular specimen to verify the force decay over a period of time for TPV followed by comparison of CAE simulation to physical test results. Finally explains about the flexible airdam parking simulation methods and the shape recovery of airdam over a period of time. The prediction of CAE to the lab testing performed on actual airdam results is provided.