Testing the blast response of foam inserts for helmets

Area of Science:

• Materials Science
• Biomechanics
• Military Engineering

Background:

• Modern combat helmets are designed for blunt impact and ballistic protection, but lack standardized blast protection.
• Integrating blast protection into existing helmet constraints (mass-volume) is challenging due to limited space for shockwave absorption.
• Current helmet designs utilize foam padding for comfort and standoff, but its efficacy against blastwaves is not fully optimized.

Purpose of the Study:

• To investigate the blast mitigation capabilities of alternative open-cell polyurethane foam materials.
• To compare the performance of novel foam specimens against existing helmet foam under blastwave conditions.
• To assess the relationship between foam mass, thickness, pore density, and blast impulse transmission.

Main Methods:

• Blastwaves were generated using an air-driven shock tube.
• Open-cell polyurethane foam specimens of varying pores per inch and thicknesses were tested.
• Performance was evaluated by measuring blast mitigation behavior and transmitted impulse.

Main Results:

• Tested foam samples demonstrated comparable blast mitigation performance to existing helmet foam.
• Novel foam specimens achieved comparable performance at a lower mass.
• A positive correlation was observed between increased foam mass and increased transmitted impulse.

Conclusions:

• While novel foams offer comparable blast protection at lower mass, they do not surpass existing helmet foam.
• Increased helmet foam mass may inadvertently increase the transmitted impulse during a blast event.
• Further research is needed to optimize helmet design for blast protection, considering the risk of exacerbating blast-induced mild Traumatic Brain Injury (bTBI).