Mechanical properties and non-homogeneous deformation of open-cell nickel foams: application of the mechanics of cellular solids and of porous materials

The mechanical properties of open-cell nickel foams are investigated for th e range of densities used in industrial applications for energy storage. Th e obtained Young's modulus, compression yield stress and tensile fracture s tress are compared to the predictions of models based on periodic, Penrose and Voronoi beam networks. It is found that Gibson and Ashby's model [L.J. Gibson, M.F. Ashby, Cellular Solids, Cambridge University Press, Cambridge, 1998] provides the proper scaling laws with respect to relative density fo r almost all investigated properties. The strong anisotropy of the observed overall responses can also be accounted for. The two-dimensional strain fi eld during the tension of a nickel foam strip has been measured using a pho tomechanical technique. Non-homogeneous deformation patterns are shown to a rise. The same technique is used to obtain the strain field around a circul ar hole in a nickel foam strip. The observed deformation fields are compare d to the results of a finite element analysis using anisotropic compressibl e continuum plasticity. (C) 2000 Elsevier Science S.A. All rights reserved.