In the United States pedestrian fatalities in vehicle impacts have increased over the last 40 years and pedestrians who use wheelchairs (seated pedestrians) have higher mortality rates than standing pedestrians in vehicle impacts. Standing pedestrian protection has generated increased attention and regulatory action but seated pedestrian protection has not been investigated or regulated. To investigate standing pedestrian safety researchers use finite element models of the human body and simulate vehicle impacts. Finite element models can be useful but they are limited by their biofidelity, and often simplify the complex anatomy of the human body for the sake of computational expense. If modeling results are to be taken seriously to investigate standing and seated pedestrian protection, then further model development and validation is necessary.
In this dissertation a finite element model of a male 50th percentile standing pedestrian was enhanced and validated for use in vehicle impact simulations. The standing pedestrian model lower body was further enhanced and validated to study the importance of stabilizing components of the knee. These updates to the standing pedestrian knee joint were imported into an occupant model and further validated in occupant loading scenarios. The updated standing pedestrian was used to explore the effect of modeling component failure on vehicle impact. Simplified and detailed occupant models were used to model seated pedestrians in vehicle impacts to explore seated pedestrian injury risks. The seated pedestrian head and brain typically reported the highest risks of injury, usually because of head-ground contact. A lap belt, airbag vest, and bicycle helmet were tested on the seated pedestrians. The lap belt and airbag vest typically increased injury risks and the bicycle helmet reduced injury risks. The work presented in this dissertation may inform future modelers, vehicle designers, and safety equipment developers on standing and seated pedestrian safety. / Doctor of Philosophy / In the United States pedestrian fatalities in vehicle impacts have increased over the last 40 years and pedestrians who use wheelchairs (seated pedestrians) have higher death rates than standing pedestrians in vehicle impacts. Research studies have examined how to protect standing pedestrians, but not seated pedestrians. The goal of this work was to begin investigating seated pedestrian safety.
To investigate standing pedestrian safety researchers use computer models (finite element models) of the human body and simulate vehicle impacts. These finite element models can be useful but they are limited by how life like they are. If modeling results are to be taken seriously to investigate standing and seated pedestrian protection, then further model improvement is necessary.
In this dissertation a finite element model of an average North American male standing pedestrian was improved for use in vehicle impact simulations. The standing pedestrian model lower body was further improved to study the importance of stabilizing components of the knee. These updates to the standing pedestrian knee joint were imported into a seated model with the same anatomy. Simplified and detailed seated models were used to model seated pedestrians in vehicle impacts to explore seated pedestrian injury risks. The seated pedestrian head and brain typically reported the highest risks of injury, usually because of head-ground contact. A lap belt, airbag vest, and bicycle helmet were tested on the seated pedestrians. The lap belt and airbag vest typically increased injury risks and the bicycle helmet reduced injury risks. The work presented in this dissertation may inform future modelers, vehicle designers, and safety equipment developers on standing and seated pedestrian safety.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/115356 |
| Date | 06 June 2023 |
| Creators | Grindle, Daniel Mark |
| Contributors | Engineering Science and Mechanics, Untaroiu, Costin D., Gabler, Hampton C., Gayzik, Scott, De Vita, Raffaella, Kemper, Andrew R. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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