Assessment of Head Injury Criterion Score of Shock Attenuation Material Employed around Playground Equipment Using Nonlinear Spring Contact Model

Abstract

In order to investigate the influence factors on HIC (Head Injury Criterion) score of shock attenuation materials employed around playground, impact tests were carried out in accordance with ASTM standard. Four kinds of the commercial shock attenuation materials were employed for the test. The apparatus is composed of the missile made from aluminum alloy with a mass of 4.6 kg and a triaxial accelerometer. The higher the missile was dropped, the more HIC score increased. The HIC score depended on the peak deceleration in collision. From the time-frequency analysis, it was obvious that HIC score depended on the characteristic frequency of the vibration system in collision between the missile and the shock attenuation material. There was sufficient evidence to suggest that the use of a simple vibration system with a nonlinear hardening spring is beneficial to assess HIC score and peak deceleration for the shock attenuation material.