摘要：
目的 构建三维有限元模型,并探讨颈动脉爆炸冲击伤的生物力学机制.方法 基于1名健康男性志愿者头颈CT血管造影(CTA)影像学数据,应用Mimics软件提取三维几何模型.应用Geomagic Studio软件对几何模型进行颈动脉、软组织非均匀有理B样条(NURBS)曲面拟合,得到三维实体模型.应用HyperMesh软件进行体网格划分,得到包括动脉血管、血液及周围软组织的颈动脉三维有限元模型.设置材料参数及边界条件,设置血管壁破裂损伤阈值为1 MPa,在LS-DYNA软件中模拟颈部距MK3A2型手榴弹80,70和60 cm爆炸冲击致伤颈动脉的动态过程,输出冲击波波形、超压峰值,输出应力云图分析损伤形态及应力分布,输出应力时间曲线分析力学变化.结果 距爆心80,70和60 cm时,冲击波超压峰值分别为0.45,0.63和0.96 MPa.80 cm时血管壁应力峰值为0.43 MPa,管壁尚未破裂;70 cm时,头臂干应力峰值大于1 MPa,出现较小破裂;60 cm时,头臂干和升主动脉应力峰值均大于1 MPa,出现明显破裂;双侧颈总动脉根部、头臂干、升主动脉等部位血管前壁为高应力集中区,表现为损伤破裂高发区.结论 成功构建颈动脉爆炸冲击伤有限元模型,可以用于分析爆炸冲击致伤颈动脉的力学响应和损伤机制.爆炸冲击过程中瞬间应力突变达到或超过血管壁损伤阈值是其损伤及破裂的主要致伤机制;距爆心为60及70 cm时,管壁应力峰值大于1 MPa,即可出现颈动脉破裂.可为颈动脉爆炸冲击伤临床救治和损伤防护提供参考.%Objective To construct a three-dimensional finite element model to investigate the biomechanical mechanism of carotid blast injuries.Methods Based on the head and neck CT angiography data of a healthy male volunteer,the 3D geometric model was extracted by Mimics software.The 3D solid model was obtained by fitting the geometric model to the non-uniform rational B-splines (NURBS) by Geomagic Studio software.The mesh of blood vessels,blood and soft tissue was divided by HyperMesh software to obtain the three-dimensional finite element model of the carotid artery.The material parameters and boundary conditions were set,and the vessel wall rupture damage threshold was 1 MPa.The dynamic process of carotid injury caused by MK3A2 grenade explosion shock wave at the distance of 60,70 and 80 cm to the neck was simulated using the LS-DYNA,generating the shock waveform and peak overpressure.The stress cloud map was used to analyze the stress distribution and damage morphology,and the stress curve was used to analyze the mechanical changes.Results The peak values of shock wave overpressure were 0.45,0.63 and 0.96 MPa at the distance of 80,70 and 60 cm away from the explosion center,respectively.At 80 cm,the peak stress of vessel wall was 0.43 MPa,and the vessel wall was not ruptured;at 70 cm,the peak stress of anonyma was greater than 1 MPa,which resulted in small rupture;at 60 cm,the peak stress of both anonyma the ascending aorta were greater than 1 MPa,leading to obvious rupture.The root part of the common carotid artery,anonyma and the arch of the aorta were high stress concentration areas,manifested as high-prevalence areas of damage and rupture.Conclusions The finite element model of explosive carotid artery injury is successfully constructed,which can be used to analyze the mechanical response and damage mechanism of carotid blast injuries.The main cause of injury and rupture is that the sudden change of stress in the process of explosion shock reaches or exceeds the threshold of vascular wall injury.Carotid artery rupture will occur when the vessel wall stress peak is greater than 1 MPa at 60 and 70 cm away from the explosion center,providing references for the clinical treatment and injury prevention.
