[PO-O1] Poster Session 1

[P1-77] A two degree-of-freedom extension to the Prandtl Tomlinson-model for friction strengthening in layered materials

^○David Andersson^1,2, Astrid de Wijn² (1.Department of Physics, Stockholm University, Sweden, 2.Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology, Norway)

The Prandtl Tomlinson-model model has been exceedingly successful in describing the stick-slip friction response signal observed in atomic systems. However, recently it has been observed in both experiments and MD simulations that layered materials exhibit an initial period of friction strengthening, which is not found within the Prandtl Tomlinson-model [1][2]. Furthermore, out-of-plane bending has been proposed as a driving mechanism for this friction strengthening regime [2][3]. In this paper we propose an extension to the Prandtl Tomlinson-model to account for friction strengthening. We show that this model successfully exhibits friction strengthening for a wide range of parameters, and that it is consistent with the out-of-plane bending hypothesis as well as previous experiments. Moreover, we make predictions as to the importance of commensurability for friction strengthening in these systems.

[1] Frictional Characteristics of Atomically Thin Sheets, Lee at al, Science 2010, doi: 10.1126/science.1184167
[2] The evolving quality of frictional contact with graphene, Li at al, Nature 2016, doi: 10.1038/nature20135
[3] Flexible graphene strengthens friction, de Wijn, Nature Communication 2016, doi:10.1038/539502a