基于有限元法分析肋骨骨折致伤方式

Analysis into Injury Mode of Rib Fracture Based on Finite Element Method

本研究利用有限元法对拳击、胸外按压致肋骨骨折进行模拟,以期为肋骨骨折致伤方式分析提供一种可视化、可量化的辅助技术。通过采用有限元法分别模拟:1)设置拳头模型以6 m/s击打THUMS4.02(Total Human Model for Safety 4.02)人体模型的左胸;2)设置按压锤模型以400 N竖直向下的力按压THUMS4.02人体模型的心前区。比较二者模拟结果的肋骨骨折分布、形态特点,从生物力学角度分析二者的损伤机制,并将模拟结果与文献报道进行比较。模拟结果显示:1)肋骨骨折形态、分布:拳击致肋骨骨折的断端形态为向内弯曲,分布于直接击打处;按压胸部致肋骨骨折的断端形态为向外翻折,分布在肋骨非直接受力处。2)生物力学响应:拳击胸部时,应变集中分布在拳击肋骨处,击打处肋骨外侧面产生压应力,内侧面产生拉应力。按压胸部时,除按压处存在应变分布外,按压侧的肋骨腋前线处出现明显应变分布,腋前线处肋骨外侧面产生拉应力,内侧面产生压应力。本研究模拟结果均得到文献支持,提示利用有限元法可实现对肋骨骨折致伤方式可视化、可量化的辅助性分析与解释。

This study is intended to provide a visual and quantifiable auxiliary technology for analysis of rib fracture injury mode.The rib fracture caused by boxing and chest compression is simulated by the fi nite element method:(1)The fi st model is set to hit the left chest of THUMS4.02(Total Human Model for Safety 4.02)at the speed of 6m/s.(2)The pressing hammer model is set to presses the precordial region of THUMS4.02 with a vertical downward force of 400 N.Distribution and morphology of rib fractures shown by the simulation results were compared,and the injury mechanism of the two was analyzed from the perspective of biomechanics.The simulation results are compared with those reported in the literature.The simulation results show that:(1)Shape and distribution characteristics of rib fractures:the shape of the broken ends of rib fractures caused by boxing is inward bending,and the fractures are distributed at the direct hitting positions of the ribs.The shape of the broken ends of rib fractures caused by chest compression is outward bending,and the fractures are distributed in the nondirect stress areas of the ribs.(2)Biomechanical response characteristics:when boxing the chest,the strain is concentrated in the position of the boxing ribs.Compressive stress is generated on the outer side of the rib at the striking position,and tensile stress is generated on the inner side.When pressing the chest,in addition to the strain distribution at the pressing position,there is another obvious strain distribution at the front line of the rib axillary on the pressing side of the chest.The lateral surface of the rib at the axillary front line generates tensile stress,and the medial surface causes compressive stress.The literature supports the simulation results,suggesting that the fi nite element method can be used to realize visual and quantifi able auxiliary analysis and interpretation of the injury mode of rib fracture.