The present thesis comprises the experimental and numerical analysis of the damage and failure behavior of ductile metals under non-proportional loading. For this purpose, biaxial experiments and corresponding numerical simulations are performed and analyzed with special specimens. A thermodynamically consistent anisotropic continuum model is presented, which takes into account the micromechanical damage mechanisms as a motivation for a phenomenological description of the damage behavior as a function of stress state. With the help of a numerical algorithm based on the inelastic predictor method, the constitutive relations of the model are implemented in the commercial program package Ansys Classic APDL and relevant aspects of the finite element method are briefly presented. In the experiments, non-proportional load paths are investigated by sequential loading of biaxial notched cruciform specimens made of metal sheets with different loading ratios. The experimental findings are compared with results of proportional experiments and corresponding numerical simulations. Thereto, strain fields of the critical areas of the specimens are analyzed by means of digital image correlation technique and show very good agreement with numerically predicted fields. Evolution of the numerically predicted plastic and damage equivalent strains illustrate their load path dependence. The numerical results are also confirmed by images of fracture surfaces taken with a scanning electron microscope. This experimental-numerical methodology is therefore suitable for developing and validating general modeling approaches and is characterized by almost arbitrarily definable load paths with changes in stress states occurring in industrial applications.    «

The present thesis comprises the experimental and numerical analysis of the damage and failure behavior of ductile metals under non-proportional loading. For this purpose, biaxial experiments and corresponding numerical simulations are performed and analyzed with special specimens. A thermodynamically consistent anisotropic continuum model is presented, which takes into account the micromechanical damage mechanisms as a motivation for a phenomenological description of the damage behavior as a fu...    »