Influence of property gradient on the behavior of cellular materials subjected to impact loading

Abstract

Recent manufacturing advances offer the possibility of introducing controlled porosity gradients in metallic-based cellular materials (foam, hollow spheres), which are promising structural materials used in applications involving lightweight structures, impact energy absorption, acoustical wave attenuation, etc. However, the influence of such porosity gradients on the overall mechanical properties of these cellular materials still lacks understanding. This paper presents a study of such porosity gradient influence using numerical simulation. Basic material behavior of a given sphere size is experimentally characterized using a recently developed testing device - a 60 mm diameter nylon Hopkinson bar system, which provides an interesting solution for both the impedance match and reasonable specimen size. Numerical results using realistic material constants permit the determination of optimized porosity gradient influence on various properties such as impact resistance, thermal diffusion, etc. © 2008 American Institute of Physics.