MODELING IMPACT DEFORMATION OF FOAM-PLATE SANDWICH SYSTEMS

Foam-plate sandwich systems comprising ten layers of crushable polyure thane foam separated by mild steel plate inserts are subjected to impa ct deformation at velocities ranging from 3 to 8 m/s using a drop towe r. Four geometrical arrangements, namely uniform-width, tapered-width, hourglass and double tapered-width profiles, are studied to identify the effects of varying the distribution of structural compliance and i nertia on impact response. The investigations focuses on the force tra nsmitted through the sandwich systems and the development of deformati on. A one-dimensional mass-spring chain model is formulated to describ e the observations. Both theoretical and experimental results indicate that the systems geometry has a significant influence on the developm ent and distribution of deformation and consequently, the force-time r esponse. The theoretical model provides reasonable predictions of the final damage distribution in each system and good correlation is obser ved between the theoretical and experimental transmitted force respons e in terms of overall behaviour. In essence, the study shows how the i mpact force transmitted by an energy-dissipating system can be control led by manipulating the distribution of inertia and compliance within the system. (C) 1997 Elsevier Science Ltd.