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

Yuji Ohue, Keita Miyoshi

Faculty of Engineering, Kagawa University, Takamatsu, Japan.
Graduate School of Engineering, Kagawa University, Takamatsu, Japan.

DOI: 10.4236/ojsst.2014.42009                

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.

Keywords

HIC, Playground, Shock Attenuation Material, Collision, Nonlinear Spring Contact Vibration Model, Wavelet Transform

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Altman, A., Ashby, K. and Stathakis, V. (1996) Childhood Injuries from Playground Equipment. Hazard, 29, 1-13.
[2]	Macarthur, C., Hu, X., Wesson, D.E., et al. (2000) Risk Factors for Severe Injuries Associated with Falls from Playground Equipment. Accident Analysis & Prevention, 32, 377-382. http://dx.doi.org/10.1016/S0001-4575(99)00079-2
[3]	Japanese Ministry of Health, Labour and Welfare (2001) Investigation Report of Accidents in Playground 2001. (In Japanese) http://www.mhlw.go.jp/houdou/0110/h1029-3.html
[4]	Ramsey, L.F. and Preston, J.D. (1990) Impact Attenuation Performance of Playground Surfacing Materials. US Consumer Product Safety Commission, Washington, D.C.
[5]	Bullen, F. and Jambunathan, J. (1991) The Design and Selection of Undersurfacing Systems for Children’s Recreational Areas, Australian Civil Engineering Transactions. The Institution of Engineers, CE33, 263-268.
[6]	Mack, M.G., Sacks, J. and Thompson, D. (2000) Testing the Impact Attenuation of Loose-Fill Playground Surfaces. Injury Prevention, 6, 141-144. http://dx.doi.org/10.1136/ip.6.2.141
[7]	McElhaney, J. (1976) Biomechanics—Head Injury Criteria. Polymer Mechanics, 12, 411-429.
[8]	Mallat, S. (1998) A Wavelet Tour of Signal Processing. Academic Press, Cambridge.
[9]	Ohue, Y., Kounou, T. and Yazama, K. (2011) Diagnosis on Pitting Failure in Gear Equipment Using Time—Frequency Domain Analysis. TRIBOLOGIA—Finnish Journal of Tribology, 30, 51-59.
[10]	Ohue, Y. and Yoshida, A. (2003) New Evaluation Method on Gear Dynamics Using Continuous and Discrete Wavelet Transforms. ASME, Journal of Vibration and Acoustics, 125, 274-281.
[11]	Weaver, W., Timoshenko, S.P. and Young, D.H. (1990) Vibration Problems in Engineering. 5th Edition, John Wiley & Sons, Hoboken, 139-221.