Morphing Cover for Front Fender Opening Using SMA Hinge to Reduce Aerodynamic Drag

摘要

Reducing the aerodynamic drag for a ground vehicle can help improve the fuel economy and improve the environment. At speeds above 60 km per hour the tire rotation generates positive pressure in wheel house, while airflow around the fender due to vehicle motion generates negative pressure. Because of these two, as shown in Fig. 1, a vortex-like condition is formed, which increases aerodynamic drag. If the fender can be extended to cover the wheel house opening, it is estimated using CFD, that the aerodynamic drag can be reduced by about 7-8%. Enclosing the rear wheel would work but for the front, such a cover would interfere with the wheel during turning maneuvers. To address this challenge, we have designed a morphing cover that can change shape to avoid interference, depending on the wheel turn direction.