The SKF University Technological Centre for Grease Lubrication at the University of Twente has an opening for a PhD candidate. The goal of this 4-year project is to measure and model film thickness in grease lubricated cylindrical roller bearings. This requires a thorough understanding of Elasto-Hydrodynamic Lubrication (EHL), thin film lubrication properties of oils, and grease lubrication mechanisms. The overall result is a semi-empirical model for predicting film thickness in cylindrical roller bearings for various greases, under various conditions. This project is executed in close collaboration with SKF, a leading global bearing manufacturer, and Shell, a leading global base stock and lubricant manufacturer.

The Challenge

Bearings are the most widespread machine elements after nuts and bolts. There are more than 50 billion bearings operating in the world at any time. 80-90% of bearings are grease lubricated. The reliability or life of a grease lubricated bearing is dominated by the quality of the lubricating film that separates the rolling elements (balls or rollers) from the rings. The quality of the film is determined by its thickness and lubricity. The film thickness determines the contact intensity from the stresses caused by asperity interaction. Grease lubrication mechanisms can be complex. Unlike oil lubrication in which the contacts are fully flooded, grease lubricated contacts are often starved (with no lubricant in some regions of the contact). Severe starvation can lead to parched lubrication. The challenge here includes developing a consistent model and practical methodology for determining film thickness in cylindrical roller bearings (CRBs).

You will:

• study lubrication mechanisms in grease lubricated roller bearings;
• study grease churning and bleed behavior in a roller bearing;
• design an experimental test set-up for film thickness measurements;
• measure film thickness in cylindrical roller bearings under various operating conditions;
• further develop a film thickness model for cylindrical roller bearings;
• closely collaborate with your research team colleagues at the University of Twente;
• finish your research with a PhD thesis and publish your work in academic journals and at conferences.

• You hold a masters degree in Mechanical Engineering, Chemical Engineering or Physics;
• You have good experimental skills;
• Good knowledge and demonstrated awareness of modelling using Python, C++ and/or MATLAB;
• A strong analytical mind, an eye for detail, and a critical attitude towards assessment of experimental results;
• You are passionate about learning new concepts and doing original research;
• You are fluent in English and express yourself easily in speech and in writing.

The UT provides a dynamic and international environment, combining the benefits of academic research with a topic of high industrial relevance, excellent working conditions, an exciting scientific environment, and a green and lively campus. We offer:

• A full-time 4-year PhD position;
• We provide excellent mentorship and a stimulating international research environment with excellent facilities;
• You are offered a professional and personal development program within Graduate School Twente;
• A starting salary of €2.434 gross per month in the first year and a salary of €3.111 in the fourth year gross per month;
• A holiday allowance of 8% of the gross annual salary and a year-end bonus of 8.3%;
• A solid pension scheme;
• Minimum of 29 holidays per year in case of fulltime employment.