4H200 - Micromechanics of materials


The mechanical behaviour of materials is strongly influenced by the structure of the material at the microscopic level. For many applications, such as applications where the length scale is relatively small with respect to the size of the microstructure, it is important to understand the role of the microstructure and to couple it to the continuum response of the material. Modelling this microstructure and the interactions between the components form an important tool for this purpose. The ultimate goal is to couple the developed structure-property relationships to the processing conditions. Then, it becomes possible to choose the processing conditions and therefore influence the structure and with it the properties of a material.

In the first part of the course, an introduction into different aspects of micromechanics is given. A number of basic tools will be treated which will be used in the remaining of the course for various micromechanical concepts and theories. A number of relevant aspects from continuum mechanics will be repeated and several methodologies to describe microstructures will be discussed.

In the second part of the course, various micromechanical approaches will be treated, such as homogenisation techniques for elastic media. A number of these techniques will be built upon in various multi-scale approaches for large deformations and arbitrary material behaviour. Averaging techniques such as the Taylor and Sachs approaches will be considered. Several techniques for modelling of microstructures via representative volume elements and unit cell approaches will be treated, after which the multi-level finite element approach will be discussed. Furthermore, attention is paid to the plasticity of porous materials, for which the Gurson model will be discussed.

In part three, micromechanical approaches will be discussed that are based on physical processes in the material. In this part, the theory of crystal plasticity will be discussed, followed by the mechanics of dislocations and the used of these theories in crystal plasticity models.

Learning objectives

Becoming familiar with various aspects of micromechanics, modelling of material behaviour at different length scales and the coupling of these length scales.