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.