Characteristics and potential applications of a novel shock absorbing elastomeric composite for enhanced crashworthiness

Abstract

The impact absorbing properties of a novel class of devices comprising stout, flexible, high tensile stiffness bags filled with a blend of small elastomeric capsules and a matrix liquid are described. The devices combine the elastic impact absorbing properties of elastomeric closed cell foams with the hydraulic pressure equalisation and viscous damping properties of liquids. The capsules can take many forms, including beads of expanded foams, bubble packing and air filled, open ended tubes. The matrix liquid, which may be a Newtonian liquid or a grease, contributes lubrication, viscous damping and pressure equalisation properties. The impact absorbing characteristics of the devices are less dependent on the shape of the contact face of the impacting body, compared with elastomeric foam impact absorbers, but uniaxial stiffness decreases, as the size of impact face of the device, relative to the impact zone, increases. Problems of package leakage and weight are addressed. The novel impact absorbing properties of the devices suggest that they could have a wide range of crash protection applications, including the design of pedestrian friendly vehicle front ends, to meet pending European legislative requirements.