A critical study on phase-field modelling of fracture

• Autor(a) principal: Hugo Mouro Leão
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/37980; https://orcid.org/0000-0003-2085-1972
• topic: Phase field models of fracture; Elastic degrading models; Finite element method based phase-field models; Engenharia de estruturas; Fratura; Método dos elementos finitos

While the Griffith approach is based on a discrete description of a crack, in the so-called elastic degrading models, cracks are considered in a continuous way, and the energy released due to crack growth is controlled by the fracture energy and other material parameters, like the strength limits. Such an approach is not capable to represent the geometry of the region where the crack takes place. Also, it presents some well known limitations such as strong mesh-dependency, premature fracture initiation and instantaneous perfectly-brittle fracture. The research group where the present work takes place has a large and diverse experience concerning the formulation and implementation of models for cracking representation. A number of studies of the research group focused on the mitigation of the aforementioned limitations. Nowadays, Phase-field models have been used as an alternative approach to deal with fracture. These models consider a diffusive and smooth crack that belongs to a certain volume region where a function that describes the crack density is prescribed. Such models can detect cracks nucleation and, as their main advantage, can describe a sharp crack without worrying about the sharp crack itself. In this way, the phase-field model consists in incorporating an additional equation in the model to controls a continuous field variable that represents a smooth transition between the completely broken and unbroken material. This work is a natural consequence of the previous studies of the research group. It is a pioneer study of the group concerning phase-field models that aims to understand the main characteristics, advantages and drawbacks of phase-field models. All the computational implementations were done in the software INSANE (INteractive Structural ANalysis Environment), an open source software developed by the own research group.