1.5岁儿童头部有限元模型的建立及验证

利用1.5岁儿童头部MRI和CT扫描数据,通过医学扫描断层图像三维重构和有限元前处理,建立一个具有高度解剖学细节的1.5岁儿童头部有限元模型并赋予其最新公布的儿童颅骨材料参数。利用这个头部模型重构Loyd开展的儿童尸体头部跌落试验(17个样本),将仿真输出的加速度历程曲线和尸体试验曲线的加速度峰值、脉冲持续时间等进行对比。结果表明,该模型能够反映跌落工况中儿童头部的受载情况,具有良好的生物逼真度。30 cm跌落高度下,枕部撞击时得到最大HIC值357;不同跌落工况的头部颅内压力分析显示,儿童头部遭受撞击时,颅内压的分布满足经典的撞击压-对撞压产生理论;相比前额撞击和枕部撞击,颅顶撞击和侧向顶骨撞击的撞击侧正压力峰值较大,最大值分别为241.6 和157.3 kPa,遭受同侧脑挫裂伤的风险较高;枕部撞击工况下,撞击对侧的负压力峰值大于其他撞击工况,最大值为-74.4 kPa,遭受对侧脑挫裂伤的风险较高。跌落高度增加时,HIC和颅内压力峰值增大,损伤风险随之增加。

Development and Validation of the 1.5-Year-Old Child Head FE Model

In this paper, a 1.5-year-old child head finite element(FE) model with detailed anatomical structure was developed through medical 3D reconstruction and FE preprocess of geometrical data were extracted from a set of MRI&CT scan images of a 1.5-year-old child. The material properties of skull and sutures reported in latest pediatric cadaver tests study were implemented into the FE model. Then the model was used to reconstruct the child head drop test(including 17 samples) conducted by Loyd. Results of simulations showed the FE model had a high biofidelity and was able to reflect the load condition of child head in real drop scenes. Maximum HIC (357) was predicted for occipital impact. Analysis of intracranial pressure predicted for different impact locations revealed that the pressure distribution was consistent with the typical pattern of coup-contrecoup injury. The model predicted higher peak coup pressure (up to 241.6 and 157.3 kPa) for vertical impact and parietal impact which leads to a higher risk of coup brain contusion. The maximum negative pressure (-74.4 kPa) was observed in occipital impact which contributes to occurrence of contrecoup brain contusion. Besides, the injury risk increases with higher drop distance.