A Study of Knee Injury Mechanisms in Car-to-Pedestrian Impacts Using
Typ
Examensarbete för masterexamen
Master Thesis
Master Thesis
Program
Publicerad
2004
Författare
Yao, Jianfeng
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The aim of the master thesis was to study the knee injury mechanisms in an impact condition associated with car-to-pedestrian accidents, analyse the influences of the physical parameters on the lower extremity impact responses, and predict the injury risks under different impact conditions. The study also contributed to the evaluation of the validity of the EEVC legform model and a FE model of the lower extremity. For the purpose mentioned above, two substitutes of lower extremity were simulated by using MADYMO MBS-FEM coupling technique and RADIOSS program respectively. One was the EEVC legform model, another the human lower limb model (LLMS) developed by MECALOG in France. The knee and leg injury mechanisms were first investigated using EEVC legform model. The influence of car front structures, upper body mass and presence of tibia fracture on the calculated injury parameters was investigated using total 24 simulations. The LLMS model was refined and evaluated using published cadaver test data. Six simulations of bumper-to-lower extremity impacts were carried out under various loading conditions including two types of car front models at impact speeds of 20 and 40 km/h. The results from LLMS model simulations were analysed and compared with the results from simulations of EEVC legform impacts in terms of injury related parameters: knee shearing displacement, knee bending angle and impact forces. The results showed that the shearing and bending injuries of the knee joint were two important injury mechanisms associated with car-to-pedestrian crash accidents. During the impacts, the major parameters influencing the lower extremity injury severity were bumper stiffness, bumper height and impact velocity. It was confirmed that the upper body mass had certain influence on the knee bending angle and shearing displacement. The tibia fracture had a significant influence on the knee joint injuries. The results also showed that the EEVC legform model was much stiffer than LLMS model for both knee joint and tibia. Further improvement of EEVC legform biofidelity was suggested. The rupture mechanism of the soft tissues in the knee joint was recommended to be simulated in the LLMS model.
Beskrivning
Ämne/nyckelord
Farkostteknik , Vehicle Engineering