Development of a Methodology for Simulating Complex Head Impacts With the Advanced Combat Helmet

Area of Science:

• Biomechanics
• Traumatic Brain Injury Research
• Protective Equipment Testing

Background:

• Current Advanced Combat Helmet (ACH) blunt impact assessments rely solely on linear head response.
• This limitation overlooks rotational forces crucial for understanding diffuse brain injuries, such as concussion.

Purpose of the Study:

• To develop and validate a novel methodology for testing the ACH under complex loading conditions.
• To incorporate both linear and rotational head motion in impact assessments.
• To evaluate the impact of different dummy neck types (Hybrid III vs. EuroSID-2) on head response and estimated brain strain.

Main Methods:

• Utilized a guided, free-fall drop tower with an instrumented National Operating Committee for Standards on Athletic Equipment (NOCSAE) head.
• Attached the head to either a Hybrid III (HIII) or EuroSID-2 (ES-2) dummy neck and carriage for rear and lateral impacts at 3.0 m/s.
• Measured peak linear accelerations (PLA) and peak rotational accelerations (PRA) at the head's center-of-gravity.
• Employed the Simulated Injury Monitor (SIMon) computational model with experimental data to estimate brain strain.

Main Results:

• Rear ACH impacts showed higher PLA (22%) and PRA (7%) with the HIII neck compared to the ES-2 neck.
• Lateral ACH impacts exhibited lower PLA (33%) and PRA (35%) with the HIII neck versus the ES-2 neck.
• The ES-2 neck resulted in a 25% increase in brain strain for rear impacts and a 76% increase for lateral impacts.

Conclusions:

• The developed methodology effectively simulates complex ACH impacts, including rotational motion.
• The choice of dummy neck significantly influences head response metrics and estimated brain strain.
• This approach provides a more realistic assessment of ACH performance against diffuse brain injuries in military scenarios.