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.