Macro and micro deformations in a sandwich foam core

Most of the current theoretical and experimental investigations deal with macro/global response of sandwich materials. However, damages are often initiated microscopically. Thus it is necessary that one investigates the micro-mechanics as well as macro-mechanics damage mechanisms of such a material. Two digital random speckle techniques (one macro and one micro) are introduced to map the full field deformation surrounding a crack in the foam core of a sandwich beam. We find that at the macro-scale the deformation pattern is quite similar to that in a homogeneous and isotropic material. However at the micro-scale, the deformation pattern is quite complicated. (C) 2004 Elsevier Ltd. All rights reserved.