Use of Parametric Finite Element Models to Investigate Effects of Occupant

Katelyn Frances Klein (University of Michigan)

CHALLENGE - Lower extremities are now the most frequently injured body region in frontal crashes, accounting for 36% of all Abbreviated Injury Scale (AIS) 2+ injuries sustained by front-seat occupants. The objectives of this research were to investigate the effects of age, sex, and BMI on variations in LX geometry, material properties, body size, and body shape and to begin understanding the effects of these variations on lower-extremity injury risk

SOLUTION - This was accomplished by developing, validating, and performing simulations with male and female human body finite element models that have geometry and material properties that are parametric with age, BMI, and stature. Statistical models were linked to a baseline FE mesh of the human occupant from Toyota’s THUMS 4 model, resulting in an FE mesh with geometry and material properties that are parameterized with subject characteristics. Then validation of the ability of the femur model was done, to reproduce the responses of subjects with different geometry as possible given the available data. Frontal-crash simulations of drivers were performed, to begin exploring the extent to which variations in LX geometry, material properties, body size, and body shape with sex, age, and BMI explain the observed effects of these parameters on LX injuries in frontal crashes. 

BENEFITS -  A single femur material property was used in the validation simulations, described in the chapter on development and validation of the parametric finite element models. Optimization was performed using modeFRONTIER and resulted in a value of 140 MPa for yield stress. This value was subsequently used in all validation simulations.