This paper presents the second part of a two-part design and analysis work for crash energy management that was conducted two years ago. Part I has been presented at the 1997 ASME crashworthiness conference held in Dallas, Texas and published in the ASME proceedings AMD-Vol.225 (BED-Vol.38).
The present paper briefly reviews the components testing results and presents a detailed discussion of the CAE modeling and models results for the full front end structure of an extruded aluminum space frame. The front end structure consists mainly of a bumper, cross member, radiator support, front and backup lower rails, upper rails, shock tower support, subframe and attachments. The materials used are aluminum alloys series 5xxx and 6xxx. The 5xxx series aluminum was used only as reinforcement. The 6xxx aluminum was used as primary material for the various components as well as for reinforcing the backup lower rails.
Force-deformation response, energy absorbed during the crash event, stress distribution and failure sequences for the front end structure have been generated and plotted. A detailed discussion of the peak and mean crush load from the force-deformation response, the energy absorbing capability of the structure from the energy-deformation curve, the axial and bending stress distribution, and the order of sequence of collapse is presented in this paper. A summary list of recommendations and critical design issues is also given at the end of this paper.