Development and validation of an elderly human body model for frontal impacts

Objective The study aims to develop an elderly model occupant representative of 50th percentile 75-year-old male using the younger 50th percentile Global Human Body Models Consortium Human Body Model. Methods The 50th percentile base model was morphed to elderly anthropometry. The material properties of tissues were updated according to the aging functions from the literature. The elderly model was simulated for thoracic impact, abdomen impact, and frontal impact sled tests. The model-predicted contact force-displacement, regional body excursion, acceleration, and seatbelt force responses were compared with matched elderly postmortem human surrogate experimental data. Results The force-displacement responses for the thorax and abdomen impacts were within the experimental corridors. The head excursion in the z-direction was within the mean +/- one standard deviation experimental corridors. The correlation analysis values of the head, T1 vertebra, pelvis acceleration, and seatbelt forces signals for the frontal sled tests were 0.62, 0.72, 0.63, and 0.78, respectively, and the overall mean value was 0.69. Conclusions The developed model with the morphological and material changes representing an elderly occupant is considered to be validated under three experimental scenarios, and it can be used for crashworthiness applications (develop countermeasures) with a focus on elderly occupants. The process used in the development of the elderly model can also be used to understand the responses of elderly occupants with different postures.