The effects of obesity on occupant injury risk in frontal impact: A computer modeling approach.

摘要

Obesity is a condition that affects about 40% of US adults, and people with disabilities have a higher incidence of obesity than able-bodied individuals. Motor vehicle collisions (MVCs) are the number one cause of death in individuals under the age of 34 in the US, and people who ride in vehicles while seated in their wheelchairs are at increased risk of injury compared to people who ride in the automotive seat. Obese occupants appear to have a different risk of injury in MVCs than non-obese individuals. To reduce the risk of injury to obese occupants it is necessary to further understand the injury mechanisms to obese individuals in frontal MVCs. The purpose of this research was to investigate the mechanisms of injury and injury risk to obese occupants and obese wheelchair-seated occupants in frontal impact.;Three full body occupant models were created to investigate the effects of increased mass, changes in obese torso mechanical response and geometry, and a combination of mass and torso changes on occupant injury risk. To investigate the effects of obesity on wheelchair-seated occupants a wheelchair/occupant model was created and validated. Parametric studies were used on all the models to investigate injury risk in frontal impact.;The results show that increased mass is the most significant factor leading to injury for obese occupants. The differences in torso mechanical response and geometry as a result of increased adipose tissue in obese occupants, do not significantly affect the injury risk of obese occupants. Changes in the obese torso coupled with increased mass cause increased pelvis and chest excursion which results in increased risk of lower extremity injury. As BMI increases in wheelchair-seated occupants the risk of lower extremity injury increases, and obese wheelchair-seated occupants have a higher risk of injury to the lower extremities than obese non wheelchair-seated occupants. This research suggests that the reduction in injuries to certain body regions reported in the literature are not due to a "cushion effect," but are more likely due to altered occupant kinematics that transfer load from the upper body to the lower extremities.