Computational Methods for Ductile Fracture Modeling at the Microscale

Abstract

This paper is a state-of-the-art review of computational damage and fracture mechanics methods applied to model ductile fracture at the microscale. An emphasis is made on robust and stable methods that can handle heterogeneous structures, large deformations, and cracks initiation and coalescence. Ductile materials' microstructures feature brittle and ductile components whose heterogeneous behavior can give raise to cracks initiation due to stress concentration. Due to large deformations, cracks initiated by brittle components failure transform into large voids. These major voids interact and coalesce by plastic localization within ductile components and lead to final failure. This process can involve minor voids nucleated directly within ductile components at sub-micron scales. State-of-the-art discontinuous approaches can be applied to discretize accurately brittle components and model their failure, given that large deformations can be handled. For ductile components, continuous approaches are discussed in this review as they can model the homogenized influence of minor voids, hence alleviating the burden and computational cost overhead that an explicit discretization of those voids would require. Close to final failure, when major voids are coalescing, and the influence of minor voids becomes compa-

Numerical modeling of ductile fracture at the microscale combined with X-ray laminography and digital volume correlation

“…A sensitivity analysis to RVE sizes was carried out in [6] for 2D and 3D configurations with random voids distribution. While such analysis is easily conducted for random distributions, it is hardly applicable to real microstructures.…”

“…This methodology, which is described in more details in Refs. [6,7,10], is a promising approach for getting a better understanding of nucleation, growth and coalescence mechanisms of heterogeneous microstructures for complex loading paths. By using DVC measurements as boundary conditions for FE simulations, this approach can also be used to calibrate nucleation and coalescence criteria and could therefore be an interesting way of feeding more physical macroscopic damage models used in material forming processes.…”

“…• FE simulations at the microscale explicitly accounting for the morphology of the studied two-phase material [4,6].…”

“…FIGURE 1. Schematic representation of the methodology coupling X-Ray laminography images, DVC and FE modeling [6,7].…”

Simulation of crack propagation through voxel-based, heterogeneous structures based on eigenerosion and finite cells

“…Altogether, these requirements still pose a challenging task in computational engineering. In Shakoor et al [43] multiple approaches for simulating crack propagation on the microscale based on the Finite Element Method (FEM) for tackling these problems are examined and compared. As a continuous approach, the phase field introduced in Miehe et al [22] assumes that the sharp cracks are smoothed by a continuous damage field.…”