Investigation on vehicle occupant dummy applicability for under-foot impactloading conditions

Purpose:Under-foot impact loadings can cause serious lower limb injuries in many activities,such asautomobile collisions and underbody explosions to military vehicles.The present study aims to comparethe biomechanical responses of the mainstream vehicle occupant dummies with the human body lowerlimb model and analyze their robustness and applicability for assessing lower limb injury risk in underfoot impact loading environments.Methods:The Hybrid III model,the test device for human occupant restraint(THOR)model,and a hybridhuman body model with the human active lower limb model were adopted for under-foot impactanalysis regarding different impact velocities and initial lower limb postures.Results:The results show that the 2 dummy models have larger peak tibial axial force and highersensitivity to the impact velocities and initial postures than the human lower limb model.In particular,the Hybrid III dummy model presented extremely larger peak tibial axial forces than the human lowerlimb model.In the case of minimal difference in tibial axial force,Hybrid III's tibial axial force(7.5 KN)isstill 312.5%that of human active lower limb's(2.4 KN).Even with closer peak tibial axial force values,thebiomechanical response curve shapes of the THOR model show significant differences from the humanlower limb model.Conclusion:Based on the present results,the Hybrid III dummy cannot be used to evaluate the lowerlimb injury risk in under-foot loading environments.In contrast,potential improvement in ankle biofidelity and related soft tissues of the THOR dummy can be implemented in the future for betterapplicability.