Artificial Surface Roughness Deformation in the Starved EHL Contacts

• Published in: Tribology Online 2018/01/31, Vol.13(1), pp.1-7
• Main Authors: David, Kostal, Petr, Sperka, Ivan, Krupka, Martin, Hartl
• Format: Article
• Language: English
• Subjects: amplitude attenuation model; artificial roughness; Asperity; Deformation mechanisms; EHD; elastic deformation; Machining; starvation; Surface roughness
• ISSN: 1881-2198; 1881-218X; 1881-2198
• DOI: 10.2474/trol.13.1

Starved elastohydrodynamically lubricated contact is described as deviation from fully flooded contact due to insufficient lubricant supply. This insufficiency causes thinner lubricant film compared to fully flooded regime. Thinner lubricant film means that rolling surfaces are closer together. Each surface has its own roughness, which is created by machining of the surface and is composed by many individual asperities. These asperities are elastically deformed while passing through the contact area of the EHL contact as well as whole contact surface. It is important to know the magnitude of the deformation. Especially in the starved contact where is increased risk of surface wear due to mutual contact of asperities on the opposite surfaces. This paper presents experimental work on the topic of the surface roughness deformation, which is passing by contact. Analytical method called amplitude attenuation theory was used to predict deformation of the artificial asperity (ridge) under starved conditions. Deformations provided by predictions were compared with the experiments and from both method is clear that roughness deformation is increasing with the progressing starvation - thinning the lubricant film. Magnitude of the deformation however depends on the asperity profile.