Investigator: Ing. Vladislav Kozák, CSc.
Number of Project: GA101/05/0493
Agency: Czech Science Foundation
Duration: 01. 01. 2005 - 31. 12. 2007

Micromechanical modelling of damage and fracture has found increasing interest for many years, especially in the last decade. The identification and determination of the micromechanical parameters require a hybrid methodology of combined testing and numerical simulation. Different of classical fracture mechanics based on the assumption of continuum mechanics, the material is not uniform on the microscale but consists of various constituents with differing properties and shapes. Using this approach the concept of a representative volume element (RVE) has been introduced. In case of crack initiation the development of crack can be simulated on the base of constitutive equations for damage evaluation (e.g. the models of Gurson) or on the base of cohesive models (phenomenological approach). In case of cohesive models is necessary to identify the hypothetic crack tip to be able to identify the driving force using traction-separation law expressed in the shape of T-δ curve. The maximum value of stress T has usually the character of cohesive strength. From point a view of modelling the material separation is realized using elements (e.g. finite element method) in the interface among the classical continuum elements. The goal of this project is prediction and fracture behaviour simulation on the base of cohesive models for selected structural materials from the base principle of separation of materials.

Kozák, V., Dlouhý, I., Chlup, Z.: Cohesive zone model and GTN model collation for ductile crack growth; Materials Science Forum 567-568 ,2008, 145-148 (Materials Structure and Micromechanical of Fracture V; ISBN / ISBN-13 : 0-87849-469-3 / 978-0-87849-469-9)

Kozák, V., Dlouhý, I.: A Crack Growth Modelling in Materials with Heterogeneous Microstructure; 17th Eutopean conference on Fracture, Brno, 2008, pp. 350-357.