Reply to the discussion by Philippon, Martinie, Vergne on ?Scale and contact geometry effects in thermal EHL: Twin-disc versus ball-on-disc? by Liu, Zhang, Bader, Venner and Poll in Tribology International

Abstract
The authors appreciate the discussion from Philippon, Martinie and Vergne on our paper (Tribol Int 154,2021,106694), in which we reported scale effects in EHL friction, i.e. the reduced coefficient of friction for EHL lubricated contacts with a large radius Rx. This was explained by an increase in film thickness and thus enhanced thermal effects. Philippon et al. found three alternative effects to explain our experimental observa-tion. However, these effects were mainly proposed based on experiments carried out at a fixed Rx, which is largely irrelevant to the main concern in our work dealing with varying Rx. In this reply, the motivation of our work is explained, and the three effects proposed by Philippon et al. are briefly discussed.

Published in TRIBOLOGY INTERNATIONAL,Volume180;10.1016/j.triboint.2022.108204,FEB 2023