In 2004, graduated (BSc, Summa Cum Laude) from the Faculty of Mechanical Engineering in Technion (Israel Institute of technology). During the BSc study acquired the specializations in the fields of micromechanics and bio-mechanics. From 2004 to 2008 – the direct truck towards the PhD degree (at the Faculty of Mechanical Engineering, Technion) in the fields of contact mechanics, plasticity, rough surface analysis, tribology and adhesion. From 2009 till now, have been working in the Research & Technology Development center of SKF. The current work covers the following fields: modeling of fatigue, computational fracture and contact mechanics, viscoelasticity and creep, hydrogen diffusion/embrittlement of steels, modeling of polymers, composites and some other topics related to the computational materials science.
Hybrid bearings, i.e. bearings consisting of silicon nitride (Si3N4) rolling elements and steel rings, are superior over full-steel bearings in multiple aspects. This concerns lightness (essential for airspace and energy saving applications), higher stiffness, better resistance to wear and corrosion compared to the full-steel bearings. Thus hybrid bearings are becoming a common product available for multiple applications. Reliable operation of hybrid bearings is linked to the quality of ceramic rolling elements, and for this each ball or roller is optically inspected. This inspection aims to reject components, containing surface imperfections which during bearing operation can lead to the progression of Rolling Contact Fatigue (RCF) damage. In the case of ceramic roller (used in hybrid CRBs), the situation is more complex compared to balls, because in rollers the criticality is dependent on the imperfection location. Indeed, the edge imperfections are subjected to different stress state compared to the ones located at the raceway. A lot of work has been done for the imperfection criticality in rolling contact, however less attention was given to the roller chamfer and the end-face. Hence, the current work focus is the modeling of edge imperfections in order to assess the risk of RCF failure. Based on this knowledge the guidelines for the roller inspection will be developed. The imperfection considered in the proposed study is the surface crack which can be formed during sintering or machining process. Semi-analytical contact mechanics is combined here with the computational fracture mechanics, which is implemented using the Finite Elements (FE) method. The outcome of the FE model is the Stress Intensity Factors (SIF), which is used here to assess the risk of fatigue crack growth, related to the damage propagation and to spalling. Wide range of contact conditions (including the roller misalignment effect), different roller design and various imperfection dimensions are covered by the parametric analysis of the current work.