Service-Life Determinations of Vehicle Steering Columns By Programmed Experiments

Implementation of a three-component steering column required investigations of its service-life. Accordingly, performance data of the column and associated vehicle parameters was first recorded during actual street operation. Computer processing of the data provided collective loading specifications for simulation of the entire loading spectra. Laboratory tests were conducted on the basis of these loading specifications. The testing method may be expanded to other studies.

All five tested steering-columns fractured under fatigue trials involving maximum torques at specified rotations. Generally, these failures occurred at the locking screw hole on the splined column section. The tests showed that stresses appear in components of limited service-life under operational conditions. However, all five columns failed under conditions corresponding to service-lives of over 500,000 km.

Such test-stand experiments provide a great deal of data concerning loading characteristics of components. The testing methods are particularly significant for safety design of vehicle prototypes.