The effect of automatic brake system on the response of the lower limbs based on active muscle force

This article employs a finite element model integrated with the Hybrid III dummy to investigate how automatic braking and active muscle forces influence lower-limb injuries in frontal collisions. Prolonged braking can increase the tibial index, indicating more severe injury to the lower leg. Braking mitigated thigh injury at 50 km/h but exacerbated it at 40 km/h. Active muscle activation increased the femoral axial force and tibial index but decreased tibial and fibular peak stresses by approximately 0.006–0.009 GPa. These findings highlight the complex role of braking and muscle activation in lower-limb injuries and inform the development of advanced safety system designs.