人体胸廓三维有限元模型的建立过程和应力分布特点

Establishment process and stress distribution characteristics of three-dimensional finite element model of human thorax

目的：探讨人体胸廓三维有限元模型的建立过程和应力分布特点，以证实三维有限元模型的可靠性，为心肺脑复苏急救时胸外按压机制和效果提供生物力学依据。方法胸部多层螺旋CT扫描辅助下成功建立人体胸廓三维有限元男女模型各一个，模拟垂直胸外按压，分析人体胸廓三维有限元模型的各部位胸廓位移和应力特点。结果成功建立脊柱、锁骨、肋骨和胸骨等胸廓结构的三维有限元模型，男/女共741006/760816个节点，男/女共316034/326785个单位。参照CT影像学特点将人体胸廓三维有限元模型分为6种材料性质。模拟垂直胸外按压，向下移位最大的胸廓部位为胸骨，应力主要分布于肋骨最后部位。静态加载时，胸骨位移恒定情况下，男性所需外力明显大于女性，两者比较差异具有统计学意义（P＜0.05）。胸骨第4、5肋间、第5、6肋间达到相同位移时需要较小的外力，与胸骨3、4肋间比较差异具有统计学意义（P＜0.05）。动态加载达到相同位移时所需外力较静态加载大，且随着频率增大，胸廓实际所承受的载荷逐渐减小，在80~100次/min时，相同外力作用下胸骨位移增加，但在110次/min时胸骨位移下降。结论建立人体胸廓三维有限元模型需提供精准的胸廓组织结构信息，为人体胸廓体外按压提供生物力学依据。

Objective To investigate the establishment process and stress distribution characteristics of three-dimensional finite element model of the human thorax, to verify the reliability of 3D finite element model, and to provide biomechanical basis for cardiopulmonary cerebral resuscitation of chest compressions mechanism and ef-fect. Methods With multi-slice spiral CT scanning, three-dimensional finite element model of the human thorax （men and women） were successfully established. Simulating vertical chest compressions, the thoracic displacement and stress characteristics of each part of three-dimensional finite element model of the human thorax were analyzed. Results The three-dimensional finite element models of the spine, clavicle, rib and sternum and other thoracic struc-tures were successfully established, with 741 006/760 816 （male/female） nodes and 316 034/326 785 （male/female） units. According to the CT imaging characteristics, the models were divided into six kinds of material properties. Dur-ing simulation of vertical chest compressions, thoracic part with the maximum downward shift was the sternum, and stress was mainly distributed in the last part of the ribs. Under static loading, in case of constant sternal displacement, the force required for male was significantly bigger than that for women （P〈0.05）. The sternums in 4, 5 intercostal, 5, 6 intercostal needed a smaller force to achieve the same displacement, compared with the sternum in 3, 4 intercostal （P〈0.05）. Under dynamic loading, bigger force was required than static loading to achieve the same displacement, and as frequency increases, the thoracic actual bearing load decreased gradually. Under the same external force, the dis-placement of sternum increased at 80~100 times/min and decreased at 110 times/min. Conclusion Accurate informa-tion of thoracic tissue structure is needed for the establishment of three-dimensional finite element model of the hu-man thorax, to provide biomechanical basis for chest compression of the human thorax.