STATIC AND IMPACT CRUSHING OF LAYERED FOAM-PLATE SYSTEMS

Kinetic energy absorbing systems comprising alternating layers of poly urethane foam and steel plate inserts are subjected to static and impa ct crushing by a falling mass. Four system geometries are investigated : uniform-width, tapered-width, hourglass and double tapered-width pro files. The pattern and degree of deformation and the crushing force ar e 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 r ate effects modify the response significantly for impact loading. Alth ough the proposed analysis based on the load-deflection characteristic s of constituent layers adequately describes the global quasi-static f orce-deformation response of the systems, it does not account for the markedly contrasting dynamic behaviour. This highlights the need for c aution in evaluating impact dissipation mechanisms from purely static data and considerations. Copyright (C) 1996 Elsevier Science Ltd.