Reducing effect of softball-to-head impact by incorporating slip-surface in helmet

Abstract

In this study we explore the effect of head-helmet interaction, in an effort to better understand the contributing factors that lead to mild traumatic brain injury (MTBI). A Hybrid III anthropomorphic head-form, fit with a Major League Baseball (MLB) approved helmet, was laterally struck with a softball at the center of gravity (CG), at 50.8 mm above the CG, and at 76.2 mm behind the CG. The effect of various frictional interfaces (slip-surfaces) between the helmet padding and Hybrid III head were tested (coefficient of friction (COF) = 1.39, 0.195, 0.096). Analysis of variance compared the effects of the frictional interfaces (FI). The results showed that a slip-surface, placed between a Hybrid III head and helmet, reduced both the resultant head acceleration and the rate of acceleration change. For impact above the CG, acceleration effects showed statistical significance (F = 7.65, p = 0.0023), and Duncan's analysis showed that the mean area under the Y-acceleration curve for COF of 1.39 was greater in comparison to COF of 0.096. It is recommended that a form of slip-surface be incorporated into any head gear, to allow head-helmet relative motion, and to utilize a proper FI in any physical model analyzing the effect of helmet impact for humans. © 2011 Published by Elsevier Ltd.