Research on the effect of wearing equipment on occupant injury under vertical impact

Military personnels need to wear equipment in combat, which will affect the damage to the occupants of the vehicle when they are subjected to the vertical impact of the explosion at the bottom of the vehicle. Through the method of vertical impact test and simulation, the influence of the distribution of the wearable equipment on the occupant injury is studied in the three directions of the weight of the wearable equipment, the position of the wearable equipment, and the tightness of the contact between the wearable equipment and the body. According to the AEP55 occupant injury criterion, the pelvic z-direction acceleration and the axial force of the lumbar spine are the reference targets for occupant injury. First, through the vertical impact test, the impact of different wearing equipment weight on occupant injury is studied; then the finite element model is used. The test is verified and optimized, and the influence of the position and tightness of the worn equipment on the occupant damage under vertical impact is studied. The results show that as the weight of wearing equipment increases, the lumbar spine injury of the occupant increases, and the probability of spinal injury decreases; the closer the equipment is to the upper part of the torso, the tighter the contact with the body, the smaller the load on the lumbar spine and the spine of the occupant, the less likely to be injured. On the contrary, the closer the equipment is to the upper part of the trunk, the tighter the contact with the body, the greater the load on the lumbar and spine of the occupant, the more likely to be injured. However, compared with the other two, the effect of tightness coefficient on the results is even less obvious. The results obtained above will provide reference for the subsequent research on reducing the impact of wearing equipment on occupant injury during the vertical impact of the bottom explosion of the vehicle.