The Application of Optimization Techniques to Problems of Automotive Crashworthiness

A method for automating the selection of front-end structural stiffnesses for barrier impact standards is presented. Presently the standard analysis tool is the impact simulation method in which static nonlinear force-deformation curves of components are used in a computer integration of the equations of motion. Current design methods involve manually modifying the force-deformation curves to produce an acceptable design. This process may be significantly improved by the use of optimization methods.

An improved impact simulation model which calculates the steering column envelopment is introduced. To express the effect of passenger compartment deceleration on potential injury, a vehicle crash severity index is introduced and is shown to be positively correlated with potential injury based on the chest severity index. An optimization technique is used to find a set of design variables which will satisfy constraints placed on the above measures of crashworthiness; namely, the steering column envelopment and the vehicle crash severity index. The shape similarity of force-deformation curves from car to car for a given component suggests the use of a scale factor on the curves as a design variable.