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为预测和评判行人面部碰撞对创伤性脑损伤机理及生物力学响应,结合计算机断层扫描(CT)和磁共振(MRI)医学成像技术,建立符合中国人体特征的50百分位头颈部几何模型和有限元模型。有限元模型中颅骨与脑之间的相对运动采用切向滑动边界条件,摩擦系数定义为0.2,模拟鼻骨斜碰撞、鼻外侧软骨正面碰撞、牙齿正面碰撞、下颌骨碰撞和颧骨外侧斜碰撞等5种典型面部碰撞交通事故场景,探讨应力波在颅骨和脑内传播路径,得到颅内压力、von Mises等效应力和剪切应力等生物力学响应参数分布规律。结果显示,鼻骨斜碰撞颅内压力峰值为236.7 k Pa,von Mises应力为25.97 k Pa,超过了大脑耐受阈值;颧骨外侧斜碰撞最大横向剪切应力分别为14.56 k Pa和-18.07 k Pa,促使脑组织产生了较大的剪切变形,存在严重脑损伤风险。结论表明:面部碰撞的位置和方向是导致面部骨折严重程度的关键因素,面骨骨折的位置决定创伤性脑损伤的部位,面骨骨折都带有一定程度的创伤性脑损伤;头部受到冲击时,面部结构能够吸收大量的冲击能量来保护大脑,降低颅脑损伤的风险。
In order to predict and evaluate the mechanism and biomechanical response of traumatic brain injury caused by pedestrian facial collision, combined with CT and MRI medical imaging, a 50-inch neck geometric model conforming to Chinese characteristics was established And finite element model. In the finite element model, the relative motion between the skull and the brain is defined by a tangential sliding boundary condition. The friction coefficient is defined as 0.2, which simulates the oblique collision of the nasal bone, the frontal collision of the nasal cartilage, the frontal collision of the tooth, the collision of the mandible and the lateral collision of the zygomatic bone Five kinds of typical facial collisions and traffic accidents scene were studied. The propagation path of stress waves in the skull and brain was discussed. The distribution of biomechanical response parameters such as intracranial pressure, von Mises equivalent stress and shear stress were obtained. The results showed that the peak pressure of intracranial pressure in nasal oblique collision was 236.7 kPa and the von Mises stress was 25.97 kPa, which exceeded the threshold of cerebral tolerance. The maximum lateral shear stress of oblique collision of zygomatic bone was 14.56 kPa and -18.07 kPa , Prompting a large brain tissue shear deformation, there is a serious risk of brain injury. The results show that the location and direction of facial impact are the key factors leading to the severity of facial fractures. The location of facial fractures determines the site of traumatic brain injury. Facial fractures have a certain degree of traumatic brain injury. The head is shocked When the face structure can absorb a large amount of impact energy to protect the brain, reduce the risk of brain injury.