Finite Element Analysis of Fretting Fatigue

Abstract

In this thesis it is conducted a literature study which looks into the subcategory of fatigue, fretting fatigue. Based on the literature study, different analyses are performed with different geometries, different contact formulations, plane strain and plain stress conditions, and finally post-processing the results by analysing them and try to use pfat as a analysis tool.

The first analysis was performed on a Dog-bone geometry, where the goal was to look for convergence in the results depending on the element size in the mesh. For this a Python script was made, in order to automate the analyses. After this was done, new analyses of the same geometry were performed in order to obtain the stick/slip behaviour with its belonging stress distribution.

Afterwords a new geometry were analysed, this was the main study of the thesis. The Dovetail is a frequently used fixing for turbine blades in the aerospace industry, and has some challenges regarding what is believed to be fretting fatigue. This geometry is different from the previous one studied, but the goal was to use the first study to compare with the results for the Dovetail. It was important to identify the stick/slip behaviour here as well, and the previous work was important in order to understand the Dovetail. The results obtained gave more understanding of the stick/slip behaviour, about where the slip amplitude has peak values and the influence of the coefficient of friction regarding the slip amplitude.