Nonlinear simulations on the interaction of disorder and defects in open cell structures

Various types of defects in regular and disordered Simple Cubic open cell structures with a relative density of 12.5% are investigated by the Finite Element Method with respect to their influence on the nonlinear mechanical behavior. The three-dimensional models are based on beam elements and account for the material distribution and the deformation constraints in the vertices. Cylindrical samples are modeled consisting of some 2600 base cells with four different lattice orientations.Disordered modifications thereof are created by randomly shifting the position of the vertices within a spherical domain. Defects are introduced by removing a fixed number of struts in three different manners, i.e., randomly distributed, as small clusters, and as big clusters. The nonlinear overall mechanical behavior is predicted for uniaxial compression of the samples with various orientations of the material’s principal axes. Elastic–plastic strut material, large deformations, and localization of deformation is considered. The defect sensitivity is studied with respect to material orientation, structural disorder, and defect type.