冲击条件下骨盆动脉损伤有限元模型的建立及验证

Establishment and validation of finite element model for pelvis artery injury under impacts

目的构建并验证含动脉的骨盆-股骨-软组织复合体的三维有限元模型,研究骨盆动脉在侧向冲击条件下的力学响应。方法基于1名女性志愿者的骨盆CT图像,建立骨盆及其动脉的三维有限元模型,包括骨、动脉、周围软组织以及骶髂关节、髋关节和耻骨联合等骨盆关节软骨和韧带。采用线弹性实体单元模拟骨骼,采用非线性的弹性连接单元模拟韧带,软组织包括软骨、包裹软组织和动脉等采用超弹性材料和实体单元仿真。以22.1 kg的冲击质量,3.13和5m/s的冲击速度对坐位下的复合体进行侧面碰撞,记录模型的输出。结果计算结果与文献报道的实验结果一致。3.31和5 m/s冲击速度下动脉的最大等效应力分别为98和216 kPa,最大拉伸应变为14.9%和20%,但不至于导致动脉断裂。结论所建立的骨盆-股骨-软组织复合模型可用于冲击载荷下骨盆动脉的动态响应和损伤分析,为预测动脉损伤程度提供生物力学依据。

Objective To construct and validate a 3D finite element model of pelvis-femur-soft tissue complex including artery, and investigate the mechanical response of pelvis artery under side impact loads. Methods The 3D finite element model of the pelvis-femur-soft tissue complex was constructed from CT images of one female volunteer, including bone tissues, arteries, enveloping soft tissues, cartilage and ligaments of the pelvic joints （ sacroiliac joint, hip joint and pubic symphysis）. The whole model utilized linear elastic solid elements to simulate bone tissues. Nonlinear elastic connector elements were employed to represent ligaments. Soft tissues, including the cartilage, enveloping soft tissues and arteries, were modeled as solid elements with hyper-elastic material. Side impact was conducted on the complex with impact mass of 22.1 kg at the impact velocity of 3.13 and 5 m/s, respectively, and the output of the complex model was then recorded. Results Simulation results matched the results of pelvic side impact experiments reported in literature. When the complex model was impacted at the velocity of 3.31 and .5 m/s, respectively, the maximum equivalent stress of arteries was 98 and 216 kPa, and the maximum principle strain was 14.9% and 20%, respectively. The risk of artery injury was relatively low. Conclusions This established pelvis-femur-artery complex model was validated and thus reliable to be used for investigating the dynamical response and injury analysis on pelvis artery under impact loads, and provides some biomechanical foundation for predicting artery injuries.