New project idea: Subsurface fatigue initiation from a material- and data-based perspective

Need for company partners. Will you participate?

SIM received a new project idea “Subsurface fatigue initiation from a material- and data-based perspective”.

In the ongoing SIM SBO project Material and Signal processing-based prediction of WEC probability (MaSiWEC) the aim is to predict premature rolling contact fatigue (RCF) failures in roller bearings of the high-speed stage in wind turbine drivetrains. The involved damage mechanism, referred to as “White Etching Cracking” (WEC), has been reported to reduce the fatigue lifetime down to 30% (or even less) of its expected lifetime, leading to unforeseen turbine maintenance associated with significant downtimes and OPEX. Various potential causes for premature RCF, of which WEC formation is a symptom, have been put forward in literature. A subsurface crack initiates and grows from a stress raiser such as an inclusion; repeated rubbing between crack surfaces causes gradual microstructural alterations and thus WEC. Based on experimental studies it is postulated that the primary driver is the stress history consisting of high stress excursions occurring early in life and followed by relatively low nominal stress. There is increasing consensus that material degradation due to hydrogen (e.g. introduced as a consequence of lubricant decomposition) is a major potential contributor in many cases.

This project will target a broader range of subsurface fatigue failure cases originating from non-metallic inclusions. Such failures are reported for a wide range of applications / components such as “bearings, (crank)shafts, gears, springs and others made of materials showing a high fatigue limit”.

An objective of the project is to reveal the underlying responsible mechanism for damage or failure from a microstructural point of view. Due to the increasing consensus that hydrogen is a major potential contributor to material degradation, determining the triggers for crack initiation, an experimental methodology needs to be developed taking into account combined impact of hydrogen and variable amplitude loading. This knowledge is currently lacking and will allow developing strategies for improved structural lifetime. A thorough experimental validation of fatigue lifetime predictions is essential.

Interested in this project idea? You can find more information in this one pager. Target date for project submission at VLAIO: September 2^nd.