Prediction of Flow Stress Curve of Metallic Foam using Compressible Constitutive Equation

Abstract

Deformation of metallic foams in forming processes is complicated due to large volume change so that the prediction is not easy. In this study, cylindrical billets of open-cell type nickel foam were compressed uniaxially. Multi-step compression tests were also conducted to reveal changes in apparent density and diameter during the compression. For numerical prediction, Oyane's yield criterion and the associated flow rule were assumed. With considering volume change in the compression, incremental analysis was performed. Changes in apparent density, diameter and flow stress curves were successfully reproduced with constants a=2.12, m=0.3 and n=2.0.