Lap belt-induced Iliac Wing Fracture Risk Curve Development for Female PMHS in Frontal Sled Tests

Area of Science:

• Biomechanics
• Injury Mechanics
• Automotive Safety

Background:

• Seat belts are primary restraints in autonomous vehicles.
• Understanding female pelvic injury biomechanics is critical for safety.
• Previous research has not fully characterized iliac wing fracture thresholds.

Purpose of the Study:

• Estimate female pelvis iliac wing tolerance to lap belt loading in frontal impacts.
• Investigate pelvis fracture patterns from seat belt loading in female subjects.
• Develop injury risk curves (IRCs) for iliac bone fracture.

Main Methods:

• Conducted 27 postmortem human subject (PMHS) frontal sled tests.
• Utilized female surrogates (small and obese) at 32 kph and 50 kph delta V.
• Developed IRCs based on lap belt force, considering age, BMI, and hip BMD.

Main Results:

• Iliac wing fractures matched real-world frontal collision patterns.
• Developed two sets of IRCs (Cohort A: small females, Cohort B: all females).
• At 50% probability, lap belt forces were 5.55 kN (Cohort A) and 6.24 kN (Cohort B).

Conclusions:

• Developed IRCs represent the tested female specimen characteristics.
• Increased age and decreased hip BMD elevate fracture risk.
• Higher BMI may provide a protective effect against pelvic fracture.