Material property determination of the lining layers of a versatile helmet

Abstract

Abstract. This paper deals with material property identification of a helmet lining consisting of an outer layer of an expanded polystyrene (EPS) and inner layer of an open-closed cell foam (OCCF). A combined numerical simulation and experimental testing was used for the material property identification. Compression and drop tests were performed. The ABAQUS finite element commercial code was used for numerical simulations in which the OOCF was modelled as a rate dependent viscoelastic material, while the EPS as a crushable foam. The reaction force time histories coming from the numerical simulation and the experiment have been used as a criterion for material parameter determination. After the identification of the material properties, numerical drop-tests were used to study the behaviour of a plate and a conical composite OOCF and EPS liners to decide which of them suits more for the helmet.

High-energy impact testing of agglomerated cork at extremely low and high temperatures

“…Coelho et al [21] tested mixed solutions of expanded polystyrene (EPS) and agglomerated cork when subjected to multi-impacts. A mix of rubber and cork was studied by Kottner et al [22] for one impact and compared with other fully synthetic solutions.…”

The deterioration of foamed silicone rubber in humid and hot environments

“…The impact resilience, 18,19 compression set 20,21 and stress-strain [22][23][24] were selected as the performance evaluation indices of foamed silicone rubber after ageing. In addition, observations of the structure, testing of XPS 21 and crosslinking density [25][26][27] were selected to explore the changes in the cellular structure, element content and compound structure of foamed silicone rubber before and after ageing, to explain the changes in its physical properties and ageing mechanism.…”