Numerical Study of a Novel Built-In Energy-Absorbing Component for Adaptive Steering Columns

Abstract

The steering-wheel—steering-column assemblies fitted in automobiles must have a high energy absorption performance in order to minimize occupant chest injuries in the event of a collision. This paper proposes a novel built-in energy-absorbing (EA) component which causes the impact load transmitted to the occupant to vary in accordance with the crash severity and the occupant mass. A finite element (FE) model of the steering-column system is constructed on the basis of realistic product computer-aided design data, and a series of LS-DYNA simulations are performed to examine the dynamic responses of the steering wheel and steering column in body block impact tests performed using body blocks of different weights. The validity of the FE model is confirmed by comparing the numerical results for the torso force profile over the duration of the impact with the experimental results obtained in two standard body block tests. The validated model is then used to examine the energy absorption performance of the proposed EA device consisting of a hollow cylindrical tube patterned with an array of circular openings. The simulations focus specifically on the effects of the total hole-opening area, the cylinder thickness, and the cylinder material on the torso force profile over the duration of the impact. It is shown that, given an appropriate specification of the design parameters, the proposed EA device satisfies the peak load requirement specified in the FMVSS 203 standard and absorbs 163 J and 235 J of the impact kinetic energy for body block weights of 24 kgf and 34 kgf respectively.