An empirical and a theoretical analysis is developed and employed to predict the stiffness of doubly curved surfaces such as those found in exterior automotive body panels. The dependent variable stiffness is a function of the independent panel variables which are:
Panel principal radii of curvature.
Panel chord lengths.
Panel boundary conditions.
The empirical analysis based on measurements made on actual automotive panels substantiates the theoretical analysis based on finite-element computer techniques. Finally, the finite-element technique is used to compute the curvatures required for an aluminum panel to maintain the same stiffness as a steel panel.