中文摘要：

汽车前碰撞事故中在冲击力作用下乘员股骨经常产生骨折创伤.为研究乘员股骨在不同的轴向压力--弯矩作用下的损伤机理及其耐受限度值,首先建立了一个较为精细的50百分位乘员的坐姿下肢有限元模型,并通过模拟股骨动态三点弯曲及下肢的轴向膝部冲击实验对模型的有效性进行了验证.在此基础上,针对股骨在轴向压力--弯矩载荷下的断裂失效分别进行了曲梁力学模型分析及有限元虚拟实验研究.结果表明：股骨骨折位置依赖于膝部轴向压力及弯矩的载荷大小的变化,在预加载弯矩从0增加到676Nm时,股骨失效部位由股骨颈部转移到股骨干末端区域;失效部位发生在颈部及股骨干时的最大力矩分别为285～296Nm和381～443Nm.股骨损伤机理的分析结果阐释了在膝部轴向冲击实验中失效部位位于股骨颈部,而在汽车前碰撞事故中仍有大量的股骨干骨折出现的原因.

英文摘要：

Occupant femur fractures occur frequently under compression-bending load in the frontal crashes of passenger cars. In order to explore the injury mechanisms and tolerances of occupants＇ femur in this load condition, a finite element model of the lower extremity in the sitting posture was developed based on the anatomy of a 50th percentile male. Then the model was validated against two types of cadaver tests, including three-point dynamic bending test of the femur and the axial impact test on the knee-thigh complex. A study of femur fractures under compression-bending load has been carried out using an analytical model of the curved beam. Furthermore, six virtual tests were conducted using the validated finite element model. The results show that the location of bone fractures and the tolerance of the femur depend on both bending load and axial compression. With the increasing preload of the bending moment from 0 to 676 Nm, the femur fracture location was shift from the femoral neck to the shaft. Regarding the tests with fractures occurring in the femoral neck, the tolerance of the femur is between 285 and 296 Nm. For the other tests with fractures located in the femoral shaft, the tolerance of the femur is between 381 and 443 Nm. The results indicated that the femur fractures always occurred at the femoral neck in axial impact tests on the knee-thigh complex, but in real world car frontal impacts the femoral shaft fractures can be observed frequently.