人上颌骨爆炸冲击伤有限元仿真模拟及生物力学分析

Biomechanical analysis of blast injury to human maxilla by finite element method

目的采用有限元法构建人颌骨模型动态模拟爆炸条件下上颌骨致伤过程,探讨上颌骨生物力学变化。方法获取1名成年男性颌面部CT数据,利用Mimics、Geomagic Studio及Hyper Mesh软件建立人上颌骨爆炸冲击伤三维有限元模型,赋予骨组织、空气及炸药材料参数,设定颞下颌关节为铰链运动,约束枕骨大孔下缘各节点所有自由度。炸药当量设定为0. 5和1. 0 g,炸药距离设为鼻前棘水平正前方3. 0和6. 0 cm,在LS-DYNA软件中进行分析运算,并用LS-PrePost软件查看上颌骨生物力学变化情况。结果建立了人上颌骨爆炸冲击伤三维有限元模型,模拟了不同载荷条件下上颌骨动态损伤过程及应力分布情况; 3种载荷条件下均显示,颧颞缝下缘单元C VonMises应力峰值最高、颧额缝前缘单元B次之、颧上颌缝眶下缘单元A最小,骨横截面较小的部位容易出现高应力集中;爆距比爆炸当量对力学指标及损伤程度作用更明显。结论基于Hyper Mesh和LS-DYNA的有限元法可较好模拟上颌骨爆炸冲击致伤过程,可作为探讨口腔颌面部爆炸冲击伤致伤机制的可靠工具。

Objective To construct a human maxillofacial bone model by the finite element method,dynamically simulate the maxillary injury process under explosive conditions,and explore the biomechanical changes in the maxilla.Methods The maxillofacial CT data of a normal adult male was acquired. The three-dimensional finite element model of human maxillary explosive impact injury was established with software of Mimics,Geomagic Studio and Hyper Mesh. The parameters of bone tissue,air and explosive materials were set. The temporomandibular joint was set to the hinge movement. At the same time,all the degrees of freedom of the nodes were restricted at the low edge of the foramen occipital magnum. The explosive equivalent was set as 0. 5 and 1. 0 g,and the distance between the explosive and anterior nasal spine was 3. 0 and 6. 0 cm. The analysis and calculation were performed with the LS-DYNA software. The biomechanical changes in the maxilla were observed by the LS-PrePost software. Results A three-dimensional finite element model of human maxillary explosive impact injury was established,and the dynamic damage process and stress distribution of the maxilla were simulated under different loading conditions. Under the three loading conditions,the peak of Von Mises stress was the highest at unit C of the low border of sutura zygomaticotemporalis,and the second highest at unit B of the front edge of sutura zygomaticofrontalis,but was the lowest at unit A of infraorbital margin of sutura zygomaticomaxillaris. The small cross-section bone area was prone to high stress. The blast distance rather than explosion equivalent produced more effects on the mechanical parameters and severity of damage. Conclusion The finite element method based on Hyper Mesh and LS-DYNA can well simulate the process of maxillary explosive impact injury. It can be used as a reliable tool to explore the mechanism of oral and maxillofacial explosive impact injury.