Laboratory Study of Factors Influencing the Performance of Energy Absorbing Steering Systems

The study was directed toward improving our understanding how postcrash column compression and steering wheel deformation relate to the driver interaction with an energy absorbing steering system during automotive collisions. Frontal sled tests conducted at 19–37 km/h investigated the Part 572 antropomorphic dummy interaction with a ball-sleeve column steering assembly over a range of column angles and surrogate postures. Neither column compression nor steering wheel deformation correlated with the mechanical severity of the test surrogate interaction with the steering system. The steering wheel deformed before the column compressed and the degree of wheel deformation strongly depended on the surrogate load distribution, the steering wheel being an important energy absorbing element. Analysis of 154 frontal towaway accidents involving GM cars further confirmed that although steering wheel deformation and column compression may be indicative of occupant loading, they do not necessarily indicate the severity of the driver interaction with the steering system.