4K060 - Damage mechanics

Contents

Mechanical failure is an important design criterion for products and components, as well as for the processes by which they are manufactured. Unexpected failure of a component (for instance part of a car) in service may cause considerable economic damage and may compromise safety. In order to avoid such premature failures, analytical and numerical models are used in the design process to predict damage resistance. Similarly, predictive analyses are used to ensure the integrity of product and tools in forming processes such as deep drawing. On the other hand, some manufacturing processes rely on the controlled development of damage, for instance in order to separate material (e.g. cutting). Damage modelling can assist in designing and optimising these processes by predicting the shape and integrity of the resulting products.

In the first part of this course the concepts and theory of damage mechanics are reviewed. Attention is largely focused on the relatively simple case of isotropic damage in a small deformation setting. It is shown that the classical, local continuum theory yields unrealistic results for such models and thus can no longer be used. Several types of enhancement are considered which aim to remove this shortcoming.

In the second part of the course one of these enhanced theories is considered in detail. A finite element solution strategy is developed, implemented in MATLAB and tested on a number of geometries in static loading.

Throughout the course, theory is complemented by illustrations and hands-on experience in terms of programming, running analyses and interpreting results. A basic finite element program in MATLAB will be provided for this purpose. Use of a notebook is highly recommended.

Learning objectives

Modelling material degradation using continuum damage mechanics, as well as implementing and using such models in a finite element code.