Load-Deflection Analyses of Shock Mitigating Polyurethane–Silicone Foams

Abstract

Three types of polyurethane-silicone foam are analysed in terms of their compression load-deflection, static load-deflection, recovery time and matrix transition temperature characteristics. The information produced is used to discuss their suitability as shock mitigating helmet liner materials. The rate of deflection during mechanical testing is shown to be highly significant at values <400% min-1 and the compression-deflection ‘plateau’ characteristics analysed in terms of a 10% load differential. Foam type 1085–47 is demonstrated to be of potential use in single impact shock absorption contexts and types 101–38 and 1085–41 of use where repeated impacts are anticipated and there is limited time available for recovery.