Institute of Fundamental Technological Research

Internal continuum damage of solids is modelled by an arrangement of oriented cracks. The observed overall mechanical response of directionally damaged materials is anisotropic. Differences in elastic, plastic and failure anisotropics are illustrated for a homogenized damaged material and uniaxial stress experiments were performed on continuously damaged alumium alloy sheets. The stress principal directions varied with respect to those of the introduced damage tensor. Experimentally obtained values of material constants for an orthotropic homogenized solid are given. The preliminary tests allow an approach to mathematical modelling of anisotropic continuous-damage mechanical response within the tensor functions theory for two independent tensor variables.

A criterion of yielding for homogenized materials with an internal structure generated by perforation is developed using the stress and the mixed stress-perforation tensor invariants. For a square pattern of perforation an experimental homogenization procedure is used to determine components of the perforation tensor introduced. A yield condition for the studied materials is proposed and compared with experiments conceived and performed for the purpose.