Estimation of Injury Limits at Vulnerable Impact Locations Along the Forearm Via THUMS AM50 Finite Element Model at...

Area of Science:

• Biomechanics
• Automotive Safety
• Injury Mechanics

Background:

• Airbag deployment is a primary cause of upper extremity injuries in automotive collisions.
• Existing research on forearm fracture limits from airbag impacts is limited, often focusing on specific locations like the distal third or midpoint.
• Lack of consensus on the most vulnerable impact site and location variability hinders effective injury prevention.

Purpose of the Study:

• To investigate the effect of airbag impact location on forearm injury risk using a detailed computational model.
• To identify the most vulnerable anatomical surface and location for forearm fracture due to airbag deployment.
• To evaluate the predictive capability of bone geometry and soft-tissue depth on forearm injury tolerance.

Main Methods:

• Simulated airbag-level impacts on all four anatomical surfaces of the forearm using the THUMS Finite Element (FE) model.
• Analyzed injury risk across different forearm locations and surfaces.
• Employed linear regression models to correlate fracture risk with bone geometry and soft-tissue depth.

Main Results:

• The distal third of the forearm was not the most vulnerable location for fracture.
• The posterior forearm surface demonstrated the highest vulnerability to fracture.
• Strong correlations were found between forearm fracture risk and cross-sectional area, area moment of inertia, and soft-tissue depth.

Conclusions:

• Forearm fracture risk from airbag deployment is not solely determined by area moment of inertia at assumed vulnerable sites.
• Current automotive safety standards may underestimate forearm fracture risk due to a lack of focus on posterior impacts.
• Predictive models incorporating bone geometry and soft-tissue depth could enhance forearm injury tolerance assessments for improved safety system design.