颅脑组织材料参数对儿童头部冲击响应的影响

目的针对目前对儿童颅脑组织材料参数的不确定性,研究直接冲击载荷条件下颅脑组织材料参数对儿童头部冲击响应的影响。方法应用已验证的3岁儿童头部有限元模型进行冲击仿真实验,采用正交实验设计和方差分析对儿童颅脑组织材料进行参数分析。结果颅骨弹性模量对儿童头部冲击响应具有显著性影响,随着颅骨弹性模量的增加,头部撞击侧颅内压力显著减小(P=0.000),对撞侧颅内压力显著增大(P=0.000),颅骨最大Von Mises应力显著增大(P=0.000)。脑组织的线性黏弹性材料参数对儿童头部冲击响应同样具有显著性影响,随着脑组织短效剪切模量的增加,脑组织最大主应变显著减小(P=0.000),脑组织最大剪应力则显著增加(P=0.000)。结论参数分析结果可为今后儿童头部有限元模型的材料选取提供参考依据,进而提升模型在预测临床上无法通过脑CT影像确诊的脑震荡等脑损伤时的准确性。

Effects from material parameters of craniocerebral tissues on impact responses of child head

Objective In view of the uncertainties of material parameters for child craniocerebral tissues, the effects of such parameters on responses of child head under direct impact loads were investigated. Methods The impact simulation experiments were conducted under direct impact loads by using a validated finite element model of 3-year-old child head. Taguchi orthogonal method and variance analysis were performed to analyze the material properties of craniocerebral tissues in child head. Results Elastic modulus of the skull had statistically significant effects on impact responses of child head. With the skull elastic modulus increasing, the coup pressure decreased significantly (P=0.000), whereas the contrecoup pressure (P=0.000) and maximum Von Mises stress of the skull increased significantly (P=0.000). The linear viscoelastic material parameters of brain tissues also had statistically significant effects on impact responses of child head. With the increase of the short-time shear modulus of brain tissues, the maximum shear stress of brain tissues increased significantly (P=0.000) whereas the maximum principal strain decreased significantly (P=0.000). Conclusions These statistical analysis results can provide references for selecting material parameter of craniocerebral tissues in finite element model of child head, which will be helpful to improve diagnosis accuracy of brain injuries such as concussion difficult to be definitely diagnosed when using brain CT images in clinic.