RESEARCH PROGRAM

Title: Dynamic phase field simulations for failure prediction in processing

 

Name: Alexander Schlüter

(former student)

 

Project description:

 

Starting situation

In order to establish a robust and versatile method to describe crack propagation in solids, concepts of fracture mechanics and damage mechanics have recently been combined in a phase field model for fracture. The main shortcoming of current phase field models of fracture is the common restriction to linear elastic materials and to static situations. In order to take the inertia effects into account, a phase field model for brittle fracture is to be extended to dynamical situations, encountered in manufacturing situations. It is known from fracture mechanical experiments, that dynamic effects lead to complex crack patterns, such as crack branching and crack kinking. The phase field like description covers all these situations, as it requires no additional criteria for crack initiation and crack growth. However, the phase field potential and the evolution equation of Ginzburg-Landau type have to be extended to account for the kinetic energy contributions.

 

Approach

At the moment most phase field models for fracture are limited to 2D situations. However, complex failure is always related to a real 3D situation with a spatial stress and deformation state, see e.g. Figure 1. The development of a 3D phase field model for dynamic fracture is a challenging task, which can only be tackled by using high performance computing and parallel algorithms. The realization of 3D simulations of manufacturing processes and potential failure scenarios by crack propagation will therefore be an extremely interesting field of research.

Additionally, the phase field method has distinct advantages in modeling multi physical problems. In this context, it is planned to extend phase field models for fracture in order to be able to simulate processes like thermal stress cracking and laser cutting.

 

Expected Results

A 3D phase field model is developed that can be used to solve manufacturing specific problems.

 

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Figure 1 Exploding pressure vessel