人体骨盆有限元模型的建立及其在法医学鉴定中的应用价值

The Finite Element Modeling of Human Pelvis and Its Application in Medicolegal Expertise

目的建立骨盆三维有限元模型,并应用有限元法对骨盆进行损伤生物力学分析,探讨有限元法在法医鉴定中的应用价值。方法基于骨盆CT扫描图像,利用Mimics 13.1软件建立骨盆有限元模型,包括髂骨、骶骨、双侧股骨头、关节软骨及韧带,模型以CT值设定材料属性。于骶骨上终板表面沿垂直轴向下施加600N静压力,以验证骨盆有限元模型的有效性。模拟侧面撞击作用,于右侧股骨大转子表面分别加载1、2、3、4、5 kN的侧向作用力,计算骨盆模型的von Mises应力云图、位移云图及应力分布曲线。结果建立了完整的骨盆有限元模型,包括关节软骨及韧带,模型几何外形与CT数据高度吻合。站立位骨盆应力主要分布于骶髂关节及坐骨大切迹处。侧面撞击下骨盆应力集中于双侧耻骨上下支、髋关节及骶髂关节。结论本研究建立的骨盆模型具有真实、有效的骨盆力学特性,可用于进行损伤模拟,为法医学鉴定提供直观、准确的依据。

Objective To develop a novel three dimensional finite element（FE） model of the human pelvis and investigate the biomechanics of the pelvic injury and explore the applications of FE approach in forensic medicine.Methods The FE model of pelvis including bilateral iliac bones,sacrum,bilateral femurs,joint cartilages and ligaments was developed with Mimics 13.1 based on the CT images.The CT value of material properties were assigned.A static pressure of 600 N was applied at the upper surface of the sacrum endplate downwards along the vertical axis of sacral bone to validate the model.To simulate the side impacts,the lateral forces of 1,2,3,4 and 5 kN were applied to the trochanter surface of right femur,respectively.The von Mises stress contours,displacement contours and stress distribution curves were subsequently calculated.Results An integrated FE model of pelvis including the joint cartilages and ligaments was successfully established.The model geometry coincided well with the CT images.The stress distributions of pelvis in erect position mainly located near the sacroiliac joints and the greater sciatic notches.Stress concentration was found on the superior and inferior pubis ramus,hip and sacroiliac joints on both sides under side impacts.Conclusion The established FE model has accurate and reliable biomechanical features.The FE model can be used to simulate injury and provide intuitive and accurate evidence for medicolegal expertise.