Static and Dynamic Response of Novel Anisotropic Foam Concept For Protective Helmets

In this paper, a new anisotropic material concept namely composite foam is proposed as an alternative to next generation helmet liners which can potentially reduce head rotational accelerations. The Layered Composite foam concept comprises of foam layers with different densities which are glued to each other in a parallel or series configuration. Initial experiments such as static combined shear-compression and linear impact tests have been performed. The performance of composite foams has been compared with a commercial expanded polystyrene bead foam (EPS), with nominal density of 80 kg/m3, which is currently the most used material for bicycle helmets. In this study the two types of composite foam with parallel and series configuration have been produced. Combined shear compression results indicate the parallel configuration is more suitable in terms of shear-compressive properties as well as energy absorption. Moreover, linear impact results indicate that the composite foam concept can mitigate peak forces compared to a standard EPS foam.