Design and injury analysis of the seated occupant protection posture in train collision

In order to minimize injuries and protect safety of seated occupants in train collision, this study proposed a self protective posture with hands laced behind head and body curled up for occupants. Through the local sled simulation test, the effectiveness of hands laced behind head posture was verified. In order to obtain the optimal protective posture with body curled up, First, the waist angle A, leg angle B and backward rotation angle C around the hip-point H of a dummy were selected as factors to design orthogonal test with different factor levels. Then, by using the direct analysis method, the influence laws of each factor on dynamic response and injury of occupants were analyzed. Furthermore, synthesized each kind of critical injury value of human body, the radial basis function surrogate model was constructed. Combining with NSGA-II multi-objective genetic algorithm, the parameters of curled-up body posture of occupants were optimized. The balance optimal protective posture of occupants was at 40-0-08 (A-B-C). Finally, the optimal scheme was verified in the simulation system for standard collision of train at the speed of 48 km/h. The results show that after optimization, head injury of occupants reduces by 88% and axial force and bending moment of neck separately decrease by nearly 50% and 80%. Moreover, stresses on thigh bone and tibia bone decline by 53% and 56%, respectively.