Investigation of linear impact energy management and product claims of a novel American football helmet liner component

Abstract

The pursuit to abate sport-related concussion necessitates thorough evaluation of protective technologies and product claims. Therefore, the purpose of this investigation was to: (i) define the linear impulse and compression behavior of the Aware-Flow shock absorber (the primary energy managing component of Xenith X1 football helmet); (ii) characterize resultant force–time curves utilizing compressive loading behavior of foam materials; and (iii) verify and define published findings and product claims. Absorbers (N = 24) from three adult X1 football helmets were impacted at predefined velocities of 1.3, 2.3, 3.0, 4.0, and 4.7 m·s^− 1. Linear impulsive forces were ideally managed up to 3.0 m·s^− 1 (25.4 J). The foam-filled pad improved impact energy attenuation and increased velocity-specific durability. The leptokurtic region of the 4.0 and 4.7 m·s^− 1 impulse curves substantiated a third phase, defined as densification, as demonstrated by the maximum compression height approaching 90%. The adoption of elastic-plastic foam terminology was recommended based upon examination of the shock absorber design and resultant phased force-time curves. Results validated published findings on the prototype thin-walled collapsible air-filled chamber component and substantiated velocity-specific support for Aware-Flow shock absorber product claims.

Keywords:

• impact energy attenuation
• brain injury of concussion
• helmet
• energy absorber
• air chamber

Acknowledgements

The authors would like to thank Jason Townsend for his support with material acquisition.

Declaration of conflicting interests

The authors declare that there is no conflict of interest.