基于剪应变耦合等效方法的颅脑矢状面旋转加速伤耐限研究

Brain impact injuriy is the leading cause of death in traffic accidents. The researches on injuries due to brain linear impacts are carried out more often than studies on brain rotary impacts. Now, the injury tolerance of brain rotary impacts which can gain general acceptance is still not available. The reasons lie mainly in the complex brain structure, the difficulty of manufacturing the brain rotary impactting equipment and the lack of feasible researching method based on the mechanical equivalent coupling principle, etc. In fact, the brain is easier to be injuried and can subsequently obtain higher injuring severity under rotary impacts compared to linear impacts. Therefore, first of all, this item will set up a brain multi-functional rotary impactting platform. After this, the living animal brain sagittally rotary impacts will be executed and the injury tolerance will be achieved. Then, the sagittal physical models of animal and human brains will be produced and the four-point markers will be placed abroad on the models' sagittal sections. In succession, the high-speed camera and the three-dimension infrared motion analysis meter will be used to record the rotary impacting process including the exterior angular acceleration course and the shearing strain data of interior four-point markers. Thus, with the exterior angular acceleration course, the living animals' experiments and the experiments based on the animal physical brain model can be coupled equivalently. In the same way, through the maximum shearing strain data of interior four-point markers, the experiments based on the animal physical brain model can be equivalently coupled with the experiments based on the human physical brain model. Finally, according to the comparability in pathology and physiology between animal and human brain tissue, the injury tolerance of human brain under its sagittally rotary impacts can ought to be obtained.

颅脑撞击伤是交通事故中的主要致死原因，其中对颅脑直线运动致伤的研究多于旋转运动，至今尚无获得公认的颅脑旋转加速损伤耐限结论。原因主要在于颅脑结构复杂，旋转运动实验装置较难以制备，未有可行的力学等效耦合研究方法等。事实上，相对于直线运动，旋转加速运动下脑组织更容易受损且其严重程度更高。为此，本项目拟通过构建多功能颅脑旋转加速运动实验台架，首先对活体动物颅脑矢状面旋转加速运动致伤耐限进行研究。之后制作矢状半切面动物、人颅脑物理模型，将标志四点对广泛放置于矢状面脑组织内，采用高速摄像系统及三维红外运动分析仪，记录分析旋转加速运动过程中，外部角加速度历程及内部标志四点对的剪应变值。通过外部角加速度历程将活体动物实验与动物颅脑模型实验等效耦合；通过内部标志四点对最大剪应变值将动物颅脑模型实验与人颅脑模型实验等效耦合。根据脑组织病生理特点的相似性，最终可望初步获取人颅脑矢状面旋转加速运动损伤耐限。

道路交通事故已成为全世界主要的一个公共卫生问题。道路交通伤严重威胁着人类的生命健康，全世界每年约有130万人在道路交通事故中死亡。颅脑撞击损伤是交通事故中常见的伤类和主要致死原因之一。驾驶员和乘员在交通事故中的死因以颅脑损伤居多，分别占到33.8%和45.9%。相比于颅脑的线性运动，旋转运动更容易导致颅脑的严重损伤，然而，目前颅脑旋转运动致伤力学机制研究远落后于直线运动致伤力学机制的研究，且至今尚无公认的颅脑旋转损伤耐限。.本项目针对颅脑矢状面旋转损伤耐限进行了深入研究，通过构建颅脑矢状面旋转实验台架（已获发明专利授权），采用高速摄像实验系统（1000fps），以外部角加速度与内部点对最大剪应变值为耦合参数，对活体兔、兔颅脑模型、人颅脑模型进行等效耦合旋转致伤实验，获得了颅脑矢状面旋转的初步损伤耐限。.实验结果表明：活体兔矢状面旋转损伤耐限角加速度值为23500rad*sˆ-2；兔颅脑矢状面模型内脑组织的相应最大剪应变值γ为0.243，最大剪应变出现在侧脑室、胼胝体区域，时间点约为有效旋转加速开始后第12ms时刻；人颅脑矢状面旋转损伤角加速度耐限推荐值为18733rad*sˆ-2，最大剪应变出现在胼胝体与下丘脑毗邻区域，时间点约为有效旋转加速开始后第135ms时刻。.本项目成果初步揭示了颅脑旋转损伤角加速度耐限值，有望推动颅脑碰撞损伤生物力学机制的深入持续研究；该成果也有助于道路交通事故中基于颅脑伤情的碰撞边界条件鉴定研究；此外，项目成果对于汽车生产厂家的安全防护装备设计也具有一定的参考价值。