A Finite Element Parametric Study of Femur Fracture Force in Out-of-Position Seating Positions Fracture Femoral Forces to Abbreviated Injury Scale Level 2+ and 3+

This research aimed at investigating the relationship between the femur forces of an out-of-position vehicle occupant and the potential injury severity occurring to the lower extremities during a frontal car crash. A better understanding and prediction of injuries allows for deriving thresholds to theoretically define values at which injuries could potentially occur, with the purpose of guiding engineers in the design of safer vehicles. A validated Knee-Thigh-Hip (KTH) finite element model of a 50th percentile male was used with the code LSDYNA to explore injury mechanisms in frontal impacts. The KTH joints were positioned at different angles of thigh flexion, adduction and abduction. Values for the Abbreviated Injury Scale (AIS) level 2+ and 3+ were calculated using peak femur forces obtained with the FE simulations and regression equations for predicting KTH injuries developed by Kuppa [1]. The study shows that the probability of KTH bone fracture is higher when the thigh is initially abducted. The study also shows that the probability of KTH bone fracture is lower when the thigh is initially flexed, rather than in a neutral position. When considering combinations of adduction and flexion, results show that the probability of KTH bone fracture is not significantly affected by the angle of thigh flexion. On the other hand, results also show that the probability of KTH bone injury when the thigh is flexed and either adducted or abducted to a relative high angle is lower.