Investigation of cellular solids under biaxial stress states

摘要

The determination of the yield surface of cellular and porous materials requires experimental procedures under multi-axial stress states as the yield behavior is sensitive to the hydrostatic stress and as simple uniaxial tests aim only to determine one single point of the yield surface. Therefore, an experimental technique based on a plane strain test for the description of the elastic-plastic transition zone at small strain is proposed and achieved in a biaxial testing machine. A simple cubic model of a periodic cellular metal is used to demonstrate the method for materials of relatively high relative density. In contrast to common analytical and numerical models, experimental samples of the same geometry are easy to manufacture and to simulate. Furthermore, this experimental technique enables the determination of Poisson's ratio in the elastic range without any strain measurement. The experimental procedure is verified by the finite element method.