Vehicle response to aerodynamic loads

Improved fuel economy and reduced power requirement have been major goals of modern automobile designers. Improvements in these areas are usually accomplished by reducing the total structural mass and by altering the exterior body shape to reduce the aerodynamic drag. Unfortunately, changes of the exterior shape may have negative effects on the side wind response of the vehicle and can increase the chances of side wind induced accidents.

This study presents a literature survey of previous work done in the field of vehicle response to aerodynamic loads, the development of a FORTRAN 77 subroutine that produces the aerodynamic forces and moments acting on an automobile body due to a side wind, and the implementation of this routine to predict the response of a 1983 standard Ford Ranger XL truck to various wind conditions using a dynamic simulation package called ADAMS. The theory uses a quasi-static approach to calculate the aerodynamic forces and moments.

The results of this study demonstrate that ADAMS can be used as an effective tool for predicting the response of a vehicle to a side gust. The response of the truck wa^ found to be highly nonlinear. Increasing the gust strength did not only result in magnified responses, but also resulted in changes in the character of the response.