Static and impact crushing of layered foam-plate systems

Abstract

Kinetic energy absorbing systems comprising alternating layers of polyurethane foam and steel plate inserts are subjected to static and impact crushing by a falling mass. Four system geometries are investigated: uniform-width, tapered-width, hourglass and double tapered-width profiles. The pattern and degree of deformation and the crushing force are examined with respect to impact velocity, system geometry and system inertia. It is found that quasi-static force-deformation behaviour is governed by system geometry, while inertial resistance and material rate effects modify the response significantly for impact loading. Although the proposed analysis based on the load-deflection characteristics of constituent layers adequately describes the global quasi-static force-deformation response of the systems, it does not account for the markedly contrasting dynamic behaviour. This highlights the need for caution in evaluating impact dissipation mechanisms from purely static data and considerations. Copyright © 1996 Elsevier Science Ltd.