The objective of this study was to investigate the effect of sedan wheelbase size on the kinematics and injury severity of left rear-seat occupants by using the finite element (FE) modeling method. A total of 270 cases with detailed accidental information records were analyzed to define the influence laws of wheelbase size and impact speed on the injury of left rear-seat occupants. First, the THUMS (Ver. 4.0.2) FE model was used to reconstruct two small offset collisions with different wheelbases size and unbelted left rear-seat occupants, and the effectiveness of the accident model was verified. Then, seatbelts were added to the left rear-seat occupant models. Finally, LS-DYNA software was used to study the correlation among head and chest injury and five sedan wheelbases sizes (2300, 2450, 2600, 2750, and 2905 mm) at three impact velocities (54, 64, and 74 km/h). The results showed that the occupants’ chest injuries showed an upward trend at the impact velocity of 64 and 74 km/h when the wheelbases sizes was reduced to 2300 mm. This research illustrated that at higher impact velocities, excessively small wheelbases might increase the chest injury severity of left rear-seat occupants.

本研究的目的是使用有限元 (FE) 建模方法研究轿车轴距尺寸对左后座乘员运动学和伤害严重程度的影响。通过对270起事故信息详细记录的案例分析，明确轴距尺寸和撞击速度对左后座乘员伤害的影响规律。首先，利用THUMS（Ver. 4.0.2）有限元模型重构了两次不同轴距尺寸且左后座乘员未系安全带的小偏移碰撞，验证了事故模型的有效性。然后，在左侧后座乘员车型中增加了安全带。最后，使用LS-DYNA软件研究了三种碰撞速度（54，64 和 74 公里/小时）。结果表明，当轴距尺寸减小到2300 mm时，乘员胸部损伤在64和74 km/h的碰撞速度下呈上升趋势。这项研究表明，在较高的冲击速度下，过小的轴距可能会增加左后座乘员的胸部损伤严重程度。