Effect of floor acceleration on occupant’s lower limb injury and its protective measures study

The floor acceleration under a vehicle under-belly blast will directly endanger the safety of the occupant’s lower limbs. A novel lower limb protection device was proposed to reduce the damage to the occupant’s lower limbs during a blast event. First, a local equivalent model of the occupant-restraint system was established, and drop impact tests validated its accuracy. Then, taking the triangular wave as an example, the influence laws of velocity difference, pulse peak, and pulse width on the occupant’s lower limb injury were investigated to guide the design of lower limb protection devices. On this basis, a novel lower limb protection device was proposed, and structural parameter sensitivity analysis was carried out. Finally, structural optimization has been carried out to further improve the protection performance of the lower limb protection device. The results showed that the proposed new lower limb protection device could effectively reduce the impact acceleration transmitted to the occupant’s feet and provide effective protection for the occupant’s lower limbs. Compared with the initial design, the optimized lower limb protection device reduced the left and right lower tibial peak forces by 26.19% and 29.32%, respectively, and the total mass decreased by 50.7%.