Ductile fracture is the most common failure mode in metal alloys. Ductile damage in a metal usually starts at an existing flaw, such as a brittle inclusion within a grain, a precipitate at a grain boundary, or a void. Large plastic deformations lead to the progress of this damage under various stress states and through various physical mechanisms. The objective of the course is to present a complete view and the state-of-the-art of the field. Experimental observations, theoretical modeling, and computational aspects will be considered. We will elucidate the following topics:
1. Phenomenological aspects. The main experimental observations under quasi-static and dynamic loadings on structural metals will be given for different stress states, highlighting the underlying physical mechanisms of ductile fracture. The roles played by the stress state will be highlighted.

2. Approaches to ductile damage. Finite strain plasticity, continuum damage mechanics, and porous plasticity will be presented. To get a deeper insight in the ductile failure process, the course also presents micromechanics-based approaches such as unit cell calculations.

3. Localization phenomena in the ductile failure process. Micro-mechanics will be used to describe the two modes of plastic flow localization that commonly occur in the ductile fracture of structural metals, namely macroscopic localization, and void coalescence. Macroscopic localization is typically associated with the softening effect of void nucleation and growth, in either a normal band or a shear band whose thickness is comparable to the void spacing. Bifurcation and imperfection approaches to strain localization will be described. In the process of void coalescence, which can occur either simultaneously or after macroscopic localization, plastic strain localizes to the ligaments between voids. Experiments have repeatedly reported three distinct types of void coalescence: (i) internal necking, (ii) shear coalescence, and (iii) necklace coalescence.

4. Issues of ill-posedness and length scale aspects in ductile failure. Here, we will explain the theoretical background for the numerical problems usually observed in the simulations and link them to the lack of length scale in the usual local description of the plastic and damage behaviors. This gives some basis for improved modeling of these behaviors including the microstructure of the material.

5. Computational aspects. From the computational point of view, the course will provide the necessary background for the attendees to study and simulate ductile failure with non-linear finite element analyses. The finite element (FE) solver ABAQUS will be used as the main tool both with the explicit and implicit solution methods.

6. Modeling of crack propagation. Finally, all the tools developed above are gathered in the prediction of crack propagation in ductile materials. Crack propagation in ductile metals is truly multiscale, with dislocation activity affecting the micro-mechanics of voids that, in turn, influences the tearing fracture process at the engineering scale.

With these lectures, we aim to attract doctoral students, researchers and engineers interested in ductile failure of structural metals.

The objective is to provide the audience with all the tools necessary to better understand the most recent developments on the subject and so facilitate the technology transfer from research to applications.