Comparative FE analysis of lower extremity injury for hybrid III, THO/LX, and human model in NCAP frontal offset crash

Abstract

Crash injuries in lower extremities are usually not fatal but may result in long-term impairment and immobility. Current understanding of these injuries is still quite limited from the biomechanical point of view. It is known that they occur often during frontal offset collisions in which intrusion of the toe pan and instrument panel frequently occur but are not always associated with their causation. Assessment of these injuries using the Hybrid III dummy is limited because of its limited biofidelic structure and inaccurate injury criteria. Accordingly, THOR-LX, the retrofit of the lower leg of the Hybrid III, has been introduced with an improved design for ankle motion and capacity of injury prediction. In this study, the different ankle joint characteristics and outcomes of both the Hybrid III and the THOR/LX have been quantitatively analyzed for an NCAP 40% offset crash with a small size sedan. A sub-structuring scheme of isolating the occupant compartment from the full car crash simulation was adopted in order to facilitate a parametric study in which various levels of structural deformation were utilized. Biomechanical injury assessment with an FE human body model was performed in addition to the dummy models to elucidate the associated injury mechanisms. The results of this study could be practically utilized for quantifying ankle joint injury outcomes from Hybrid III and THOR/LX dummies. Copyright © 2005 SAE International.