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Industry trends towards lighter, more aerodynamically efficient road vehicles have the potential to degrade a vehicle’s response to crosswinds. In this paper, a methodology is outlined that indirectly couples a computational fluid dynamics (CFD) simulation of the vehicle’s aerodynamic characteristics with a multi-body dynamics simulation (MBD) to determine yaw, roll and pitch response characteristics during a severe crosswind event. This one-way coupling approach mimics physical test conditions outlined in open loop test procedure ISO 12021:2010 that forms part of the vehicle sign-off criterion at Ford Motor Company. The methodology uses an overset mesh CFD method to drive the vehicle through a prescribed crosswind event, providing unfiltered predictions of vehicle force and moment responses that are used as applied forces in the MBD model. The method does not account for changes in vehicle attitude due to applied aerodynamic forces and moments.

Computer aided engineering (CAE) methods have been part of Electronic Stability Control (ESC) system development since its introduction to the market in 1995, especially in the testing and verification phase. Over time, additional CAE tools and methods have been introduced, ranging from small self-learning algorithms to automatic tuning tools for individual functions. Since the end of 2009, ECE regulations have allowed the use of CAE methods for ESC homologation, and in North America, the exemption from FMVSS126 compliance for aftermarket parts was phased out in 2012. Following these legislative changes, several original equipment manufacturers, aftermarket companies and ESC suppliers are using vehicle dynamics computer simulation methods to predict ESC performance and homologate vehicles.