Modelling of the compression behaviour of metallic hollow-sphere structures: About the influence of their architecture and their constitutive material's equations

This paper is dedicated to the study of the mechanical behaviour of metallic hollow-sphere structures under quasi-static compressive loads and, especially, to the characterization of contributions of both the stacking architecture and the constitutive material's mechanical properties. Indeed, hollow-sphere structures could represent an alternative solution to classical cellular materials (like metal foams or honeycombs) for numerous structural applications like impact resistance for example. The aim of this work is to understand how the architecture of such materials governs their overall mechanical behaviour through modelling. In this work, emphasis is put on the influence of the localized plasticity and the buckling of spheres on the stacking's effective behaviour. A finite-element model is used, taking into account these mechanisms, in order to characterize how the stiffness, of both the meniscuses and the hollow spheres respectively, contributes to the effective stiffness of the stacking. The role of the stacking arrangement on its effective behaviour is studied. This paper deals also with the issue of the choice of the constitutive material's behaviour and with its influence on the effective behaviour of the hollow-sphere structure.