The impact response of motorcycle helmets at different impact severities.
Helmets reduce the frequency and severity of head and brain injuries over a range of impact severities broader than those covered by the impact attenuation standards. Our goal was to document the impact attenuation performance of common helmet types over a wide range of impact speeds. Sixty-five drop tests were performed against the side of 10 different helmets onto a flat anvil at impact speeds of 0.9-10.1 m/s (energy=2-260J; equivalent drop heights of 0.04-5.2 m). Three non-approved beanie helmets performed poorly, with the worst helmet reaching a peak headform acceleration of 852g at 29J. Three full-face and one open-face helmet responded similarly from about 100g at 30J to between 292g and 344g at 256-260J. Three shorty style helmets responded like the full-face helmets up to 150J, above which varying degrees of foam densification appeared to occur. Impact restitution values varied from 0.19 to 0.46. A three-parameter model successfully captured the plateau and densification responses exhibited by the various helmets (R(2)=0.95-0.99). Helmet responses varied with foam thickness, foam material and possibly shell material, with the largest response differences consistent with either the presence/absence of a foam liner or the densification of the foam liner.
DeMarco
Alyssa L
AL
MEA Forensic Engineers & Scientists, 11-11151 Horseshoe Way, Richmond, BC, Canada V7A 4S5.
Chimich
Dennis D
DD
Gardiner
John C
JC
Nightingale
Roger W
RW
Siegmund
Gunter P
GP
D000054:Acceleration / Q000009:adverse effects; D000063:Accidents, Traffic / Q000517:prevention & control*; D001696:Biomechanical Phenomena; D001930:Brain Injuries / Q000517:prevention & control*; D003257:Consumer Product Safety / Q000592:standards; D006259:Craniocerebral Trauma / Q000517:prevention & control*; D004867:Equipment Design; D006260:Head Protective Devices / Q000592:standards*; D006801:Humans; D009049:Motorcycles; D012449:Safety / Q000592:standards