Femur and Knee Injury Reduction by Use of Knee Bolsters in Frontal Crashes 2007-26-001
In vehicular crashes, one of the main causes for occupant injuries is uncontrolled hard contact with the vehicle interiors. Typically in frontal crashes, injuries are mainly caused due to contact with the steering wheel and dashboard.
In frontal crashes, upper leg injuries are caused due to forces applied on the knee and lower leg (tibia). This injury is a function of occupant forward movement, dashboard intrusion, dashboard stiffness and hard components behind the dashboard in the knee contact location. While trying to control the above design parameters is possible, provision of knee bolsters to limit the femur and knee injury is a more cost-effective, modular and a relatively simple countermeasure which can be used even for an existing vehicle.
Knee bolster is a mechanical energy absorbing member packaged behind the dashboard. This member crushes or folds at a predetermined load due to contact forces from the upper leg, thus controlling the resulting injuries.
This paper explains the methodology and validation process used for developing and optimizing a knee bolster for reducing knee-femur injury through a case study.